Time to loss of physical integrity of Attractive Targeted Sugar Bait (ATSB) stations in Western province, Zambia: a survival analysis

Time to loss of physical integrity of Attractive Targeted Sugar Bait (ATSB) stations in Western province, Zambia: a survival analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Time to loss of physical integrity of Attractive Targeted Sugar Bait (ATSB) stations in Western province, Zambia: a survival analysis Refilwe Y. Karabo, Masuzyo H. Mundia, Mwansa Mwenya, Kochelani Saili, and 15 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4670314/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Attractive Targeted Sugar Baits (ATSBs) are a potential addition to the integrated vector management strategy against malaria. ATSB stations utilize the attract and kill method to control mosquitoes. Each ATSB station contains a sugar bait laced with an ingestion toxicant. This study measured the duration of physical integrity of the ATSB Sarabi v1.2 station used in western Zambia as part of a Phase III cluster randomized control trial. Methods ATSB stations were installed on external walls of 304 sleeping structures, in 206 households (10–11 per cluster within 20 clusters). Monthly visits were made to assess for the presence and condition the ATSB stations from November 2022-June 2023. A rolling cohort approach was used, whereby newly installed, and replacement ATSB stations were included in the study. Information on structure construction and location of ATSB stations on walls was collected. Median ATSB survival and associated factors were analyzed with Kaplan-Meier curves and Cox-Proportional hazard models, respectively. Results Including replacements, a total of 1107 ATSB stations were installed across 304 sleeping structures and 5696 ATSB-visits were made. Common types of damage observed were holes/tears, mold, and leakage of bait. While the median survival time for the ATSB stations was five months (149 days) for all stations in the study, the median survival time was longer than the transmission season for stations installed in locations well protected by the roof (> 218 days). ATSB station survival was longer when installed on structures with thatched roofs compared to iron sheet roofs (Hazard Ratio 0.37, 95% confidence interval 0.26–0.47, p < 0.001), and where there was ‘excellent protection’ (HR = 0.36, 95% CI 0.25–0.49, p < 0.001), compared to ‘no protection’. Conclusions Study results suggest that the majority of Sarabi v1.2 ATSB stations deployed in this setting will remain intact for a 7-month seasonal deployment period if stations are installed in locations protected from rain and wind such as underneath a thatched roof. Further research is needed to understand factors that influence the physical integrity of ATSB stations in addition to those observed in this study. Malaria Attractive Targeted Sugar Bait survival Figures Figure 1 Figure 2 Figure 3 Figure 4 BACKGROUND Almost eighty percent of the global reduction in Plasmodium falciparum malaria cases has been attributed to vector control (long lasting insecticidal nets and indoor residual spraying) 1 . However, recently, the reduction in malaria cases has stalled, highlighting the need for new vector control tools for better control and ultimately elimination and eradication of malaria. Plant sugars serve as an important energy source for both male and female mosquitoes. This can in theory be targeted by providing artificial sugar source as an attractant to lure, and if combined with an insecticide, to kill mosquitoes. This approach to vector control has been called Attractive Targeted Sugar Bait (ATSB). ATSB stations are a promising innovation, and a potential addition to existing vector control tools 2 , 3 . ATSB stations thus differ from the existing recommended vector control methods that target indoor human blood feeding (Insecticide Treated Nets) and resting behaviors (Indoor Residual Spraying, IRS). In 2017, ATSB stations were shown to reduce Anopheles mosquito densities in field settings in Mali 4 , 5 . A phase III cluster randomized control trial (cRCT) was conducted in Western Zambia to investigate the efficacy of the Sarabi v.1.2 ATSB stations (manufactured by Westham Ltd., Hod-Hasharon, Israel) in reducing malaria incidence. The sustained effectiveness of many vector control products, when deployed, depends on their physical integrity and ultimately their durability (ability to resist wear and last over time). For example, Long-Lasting Insecticidal Net (LLIN) durability has been previously defined to include persistent insecticidal effectiveness, physical durability and attrition 6 – 8 . Further, Briet et al. (2020) indicate that ‘LLIN survivorship is an important precondition for use’ 6 . This means that the durability of LLINs is a critical requirement for their utilization. In the context of IRS, insecticide residual efficacy is used to characterize intervention durability or persistence in the field 9 . Due to the novelty of the Westham Sarabi v.1.2 ATSB stations, there is limited understanding of their durability, and their bio-efficacy under different conditions. In a recent study by Mwaanga et al. (2024) 2 , bio-efficacy of ATSB stations was measured for ATSB tools which remained physically intact during field deployment. The results indicated that ATSB stations which remain physically intact can also remain bio-efficacious following deployment for at least seven months in the field. However, a gap remains in understanding the physical durability and survival of the ATSB product under deployment conditions, given that there is no information on how long ATSB stations can maintain high levels of physical integrity in the field. This study seeks to ascertain the duration of physical integrity and attrition of the Westham Sarabi v1.2 ATSB stations used during the trial, an important component of the overall durability of ATSB. Factors that include the duration of physical integrity, bio-efficacy and attractancy as well as attrition are relevant in this context. The aim of this study is to assess the median time that the ATSB stations remain deployed in the field before replacement due to deterioration in physical integrity, and do not go missing, which we describe as the survival time. METHODS The study defines physical integrity of the ATSB station as remaining undamaged, intact, or without structural defect. This good condition is defined as not meeting pre-defined criteria for replacement due to holes/tears, leaks, mold, dirt, or depletion. Study site The cRCT trial was conducted in Kaoma, Luampa, and Nkeyema districts, in Western Province, Zambia from November 2021 to June 2022 and November 2022 to June 2023. The study site is described by Arnzen et al. 10 , details of the trial design are reported by Eisele et al. 11 , and the ATSB intervention is described in detail by Orange et al. 12 . The three trial districts have a combined population of 246,785 (2022 population census) 13 . The climate is tropical with a rainy season from approximately December through March 10 , which supports arable and pastoral agricultural activities. The rainy season is followed by a peak in malaria transmission from April to May. ATSB stations The ATSB Sarabi v.1.2 bait station (Westham Ltd., Hod-Hasharon, Israel) measures slightly over 24cm X 30.5cm. Each bait station has 16 cells filled with 72g of date syrup-based bait, which acts as both the attractant and sugar source, dinotefuran (0.11% w/w) the active ingredient, and Bitrex® (Johnson Matthey), a bittering agent to deter ingestion by humans. Dinotefuran, an ingestion toxicant, is a furanicotinyl (neo-nicotinoid) insecticide, which occupies and activates the nicotinic acetylcholine receptors of the mosquitoes 14 . The toxicant binds permanently to the insects’ nicotinic receptors and mimics the effects of acetylcholine, resulting in constant nerve stimulation, tremors, and eventually death 15 . ATSB station contents are contained between a white plastic backing and a black perforated membrane that allows the mosquito proboscis to penetrate and ingest the bait, while reducing the ability of non-target organisms to access the bait, as well as evaporation of volatile components in the bait including water. The white plastic backing and membrane are fused together in the 1cm spaces between the cells. Further details of the ATSB station used in this trial are reported in Orange et al. 12 . ATSB station installation campaigns ATSB stations were installed on study households as part of the second year of the cRCT in November 2022. Eligible structures that received ATSB stations were defined as those with a complete roof, at least three complete exterior walls, wall height measuring one meter or more, and structures not under construction (primarily sleeping structures and multi-use residential structures). Structures that were identified as shops, schools, churches, tobacco sheds, animal kraals, toilets, bathing shelters, and food storage shelters were not eligible for ATSB station installation. Two ATSB stations were installed on each eligible structure by trained community members (ATSB Monitors). ATSB stations were typically hung on opposite exterior walls of a structure unless adjacent walls offered better protection from rain, sun, and wind. ATSB stations were hung on walls using bamboo sticks inserted through holes on the top and bottom frames of the ATSB station. Strings or wires were wound around the bamboo sticks to attach the ATSB stations to anchored nails on the walls of the structures. Further details of ATSB station installation are available in Orange et al. 12 . Study design and data collection procedures A prospective open cohort of ATSB was nested within the routine ATSB monitoring procedures of the ATSB trial. Selected ATSB stations installed during the trial installation campaign were enrolled in this study on a first visit by the research team shortly after placement on structures in late November to early December 2022. As a rolling cohort, additional ATSB stations installed and enrolled in the cohort either on new structures, or as replacements for damaged stations were also enrolled into this study. Twenty of the 35 intervention arm clusters were purposively selected for inclusion in this study. Ten or eleven households were purposively selected from each of the 20 clusters. The enrollment visit occurred approximately two weeks after ATSB installation. On the enrollment visit (late November or early December 2022), the research team created sketch maps of the selected households, documented all the structures in each household, and recorded details of ATSB stations already present on structures from the ATSB installation campaign. Each ATSB station had a unique QR code which had been printed during manufacturing. Monthly visits were made to all enrolled households and structures. At each visit, presence or absence of each ATSB station was confirmed and location verified. ATSB stations were assessed according to pre-defined damage criteria for replacement including holes/tears, leaks, mold, dirt, and depletion 12 . Presence of mold that led to replacement was defined as fuzzy mold growth more than the size of rubber/eraser end of a pencil or layer of mold that covered at least half of the ATSB station surface. Tears/holes were defined as one or more cells being fully open. Dirt that warranted replacement was described as having at least eight cells covered in dirt. ATSB trial staff also palpated the ATSB stations to check if each of the 16 cells on each station were depleted of bait or not. ATSB stations that warranted replacement had eight or more cells flat or empty when checked with a gloved hand. A photograph of the ATSB station was also taken as evidence of its presence and condition. ATSB stations meeting the replacement criteria were replaced with a new station, and the QR code of the newly installed ATSB station recorded and enrolled into the study. During each study visit, location and characteristics of each ATSB station installation site were documented. These included the distance between the lower end of the ATSB station and the ground, the distance between the upper portion of the ATSB station and the roof (at the point where the roof and the exterior wall meet), as well as the length of the roof overhang (distance perpendicular to the outside wall). Information on the material used for construction of the structure’s wall and roof was also documented. If an enrolled structure was demolished, burned, or collapsed, this was documented, and no further visits were made to it. If a new ATSB station-eligible structure was identified at an enrolled household during a study visit, the structure was enrolled. The existing ATSB stations would then be registered, or ATSB stations installed and registered if not already present. This study was embedded in the ATSB main cRCT monitoring program; hence the ATSB stations were routinely assessed by ATSB monitors. This monitoring occurred once every two months, or sooner if damage was reported by the household. It was possible for ATSB stations to be visited more than once a month by the ATSB monitors as part of routine monitoring for the trial, and by the research team for the physical durability study. Routine monitoring visits used the same replacement criteria as this study to remove, and replace damaged or lost bait stations. Observations of ATSB stations were recorded using an android-based digital data collection tool (Commcare, Diamgi Inc., Cambridge MA, USA). Sample size The sample size was calculated following the Brookmeyer and Crowley (1982) method 16 . The median survival of an ATSB station was assumed to be 3 months, and the sample size was planned to allow for this to be estimated with a 95% Confidence Interval of 2.3–4.1 months. It was anticipated that this level of precision could be achieved if a minimum of two ATSB stations were installed and followed at each selected household, and a minimum of 10 households in 10 clusters were included. This resulted in a minimum of 100 households, and 200 ATSB stations, and potentially monitoring of more than 300 ATSB stations (including replacements) being followed for six months. Field logistics and funding permitted expansion of the study from 10 to 20 clusters, but retained a target enrolment of at least 10 households per cluster in theory allowing for a more precise estimation of the study outcome. Data analysis Data analysis was conducted using R programming language version 4.2.2 17 and packages ‘survival’ 18 , ‘survminer’ 19 , ‘frailtypack’ 20 , and ‘coxme’ 21 . Outcomes and other measures The main endpoint of the study was ATSB station meeting criteria for replacement or having been removed. The outcome event was defined as occurring when the ATSB station met the replacement criteria on the monthly durability study visit or was not found where it was expected (either replaced by routine monitoring process or lost). The ATSB stations that had not experienced an outcome event continued to be followed and monitored in the subsequent visits to the end of the study or when lost to follow up for other reasons, such as destruction or removal of the structure on which the station had been placed. Stations which did not experience an event were considered as right censored at their last visit. Right censorship occurs when the study ends or when a subject, in this case an ATSB station is lost to follow up. The true survival time is incomplete at the right side of the follow-up period 22 . Time to event was measured in days until failure/event occurred or censoring. This was defined as the number of days between the ATSB station being enrolled in the study and the date a failure/event was recorded (ATSB station was found damaged, removed from its location or other reasons that met the pre-determined replacement criteria) or the ATSB station was censored. Details of ATSB-station installation location were used to generate an indicator of protection level with three classes. “Excellent protection” was defined as ATSB stations that were either reported as “tucked under the roof overhang” on observation or where the ratio of measured roof overhang to distance from roof to ATSB stations was greater than one. “Some/moderate protection” was defined as ATSB stations that were reported as either being placed at level with the edge of the roof, or where the ratio of measured roof overhang to measured distance from roof to ATSB station was 0.5 or larger but less than one. “No protection” was defined as ATSB stations where the ratio of roof overhang size to distance from roof to ATSB station was < 0.5. Figure 1 shows photos of stations installed on study buildings as visual examples of these protection levels. The study also considered the height of ATSB station above the ground. The measurements were categorized into four groups ( 150-200cm and > 200cm between the ATSB station and the ground). Kaplan-Meier survival estimates were used to calculate the overall median survival time, and median survival time stratified by protection level. Stratified Cox-Proportional Hazard models were used to examine differences in survival by different roof materials, wall placement position, protection level and different clusters, using shared frailty methods to account for the clustering of ATSB stations within study clusters from the overall ATSB cRCT. RESULTS The study enrolled 304 eligible structures in 206 households for monthly visits. A total of 1,107 ATSB stations across 20 clusters, with a range of 32–139 ATSB stations per cluster were analyzed. For monitoring purposes 5,696 ATSB station-visits were made from November 2022 to June 2023 for this study (not including visits made by ATSB monitors). The maximum duration from the time of enrollment in the study to a final ATSB station-visit was 218 days. Sixteen structures were excluded after enrollment as they were subsequently considered not eligible because they were no longer being used as sleeping structures, or because the structure had collapsed or burned after data collection had begun. During the study, 17 newly eligible structures were enrolled at participating households, with 34 new ATSB stations installed on these structures. Table 1 Summary of structure characteristics Wall type N = 304 (%) Wood with mud plaster 109 (35.9) Cement block 72 (23.6) Mud brick, covered* 31 (10.2) Mud brick, uncovered 68 (22.4) Wood plank 14 (4.6) Thatch 10 (3.3) Roof type Iron Sheet 152 (50) Thatch 145 (47.7) Cement 5 (1.6) Wood plank 2 (0.7) *Mud bricks are covered with mud or cement plaster Among the enrolled structures, 35.9% (109/304) had wood walls with mud plaster, and half of all structures were roofed with iron sheets (152/304, 50%, Table 1 ). Table 2 indicates the distribution of all ATSB stations included in the study at any time, according to the wall type, protection level and roof type of the structures they were installed on. Table 2 Structure characteristics of installed ATSB stations Protection level of installed ATSB Excellent protection (N = 621) Moderate protection (N = 292) No protection (N = 194) Hung on wall type Wood with mud plaster 319 70 8 Cement block 20 115 126 Mud brick, covered* 65 39 6 Mud brick, uncovered 174 32 43 Wood plank 10 32 11 Thatch 33 4 0 Hung under roof type Iron Sheet 100 281 173 Thatch 521 6 0 Cement 0 0 21 Wood plank 0 5 0 *Mud bricks are covered with mud or cement plaster Overall, 48.6% of enrolled ATSB stations met criteria for failure and reason for replacement during the study period (up to 218 days). The median time (of ATSB stations) from enrollment to replacement or loss by cluster ranged from 35 days to beyond the 218 days of the study period. Nine of the 20 clusters (45%) had ATSB stations with median lifetime greater than the 218-days, indicating that in those clusters more than half of the ATSB stations enrolled at the start of the study remained hanging and intact at the end of the study period. The most common reasons for ATSB station replacement/event were holes/tears (24.3%), followed by mold (21.6%) and leaking (19.3%) (Table 3 ). Stations with two or more categories of damage contributed 2.6% of the observed reasons for replacement. 108 (20.1%) enrolled ATSB stations were replaced by trained community members during routine monitoring visits, between the scheduled visits of this study. Relatively few ATSB stations (5.6%) were missing or lost to follow up. Table 3 Reasons for ATSB replacement ATSBs N = 538 (%) Damaged: torn 131 (24.3) Damaged: mold 116 (21.6) Damaged: leak 104 (19.3) Damaged: depleted 30 (5.6) Damaged: dirty 5 (0.9) Damaged: more than one category 14 (2.6) Absent/missing 30 (5.6) Removed by community monitor* 108 (20.1) * Separate from the research team in this study, ATSB monitors visited bait stations to perform assessments of bait station condition and to remove and replace damaged bait stations during routine monitoring for the trial. A total of 569 ATSB stations were right-censored. This included ATSB stations not meeting replacement criteria at the final visit and those right censored during the course of the study (including those hung on structures that later collapsed, burned or ineligible). The median survival for all ATSB stations in this study was 149 days (95% CI: 133, 164) (Fig. 2 ), approximately 5 months. ATSB stations hung on structures with thatch roofing had the longest median survival time at > 218 days. ATSB station median survival differed according to protection level of the installation site, with median survival of ATSB stations in locations with “excellent protection” of > 218 days, while median survival time in sites with “some protection” and “no protection” were 124 days and 90 days, respectively (Fig. 3 ). Large differences in median survival time were also observed between different clusters (Fig. 4 ). The Cox-Proportional hazards model indicated that ATSB stations installed in locations with “excellent protection” had a longer survival time than those in locations with “no protection” (hazard ratio (HR) = 0.36, 95% CI 0.25–0.49, Table 4 ). ATSB stations in locations with “moderate protection” also had longer survival times compared to those with “no protection” (HR 0.62, 95% CI 0.47–0.82). Thatch roof was also associated with improved ATSB station survival (HR 0.37, 95% CI 0.26–0.47) compared to ATSB stations on structures with iron sheet roofs. Table 4 Determinants of ATSB survival, estimated by univariate Cox-proportional hazards models with shared frailty for cluster Variable Unadjusted hazard ratio 95% CI P-value Protection level Reference No protection (n = 194) Moderate protection (n = 292) 0.62 0.47, 0.82 0.001 Excellent protection (n = 621) 0.36 0.25, 0.49 < 0.001 Frailty (cluster) < 0.001 Roof material Reference iron sheet (n = 554) Cement or wood plank (n = 26) 1.32 0.79, 2.22 0.29 Thatch (n = 527) 0.37 0.26, 0.47 < 0.001 Frailty (cluster) < 0.001 Distance of ATSB to ground Reference 200cm (n = 11) 5.28 2.13, 13.12 < 0.001 151-200cm (n = 296) 1.84 1.32, 2.56 < 0.001 100-150cm (n = 633) 1.35 1.04, 1.76 0.025 Frailty (cluster) < 0.001 Shorter distance between the ATSB station and the ground was associated with improved longevity of the ATSB stations. The univariate Cox-Proportional Hazard model (Table 4 ) indicated that ATSB stations hung over 200cm above the ground were more likely to be lost or damaged compared to those ATSB stations placed 100cm or less above the ground (HR 5.28, 95% CI 2.13–13.12). ATSB stations installed at heights of 100-150cm or 151-200cm above the ground also had reduced survival compared to those placed at 1 meter or lower (HR 1.35 and 1.84, respectively). DISCUSSION This is the first study to estimate the survival time of an ATSB product during seasonal deployment to control malaria in Africa. ATSB stations installed with excellent protection had median survival times > 218 days, which is longer than the seasonal deployment period in this setting. The overall median survival time for ATSB stations was 149 days, meaning 50% of the ATSB stations were still hanging and in good condition after approximately 5 months. For comparison, the seasonal ATSB deployment period in this Zambian setting was approximately seven months (deployment in November and removal in June). There were large differences in median survival times by cluster, and according to the characteristics of the structure and location on the structure where ATSB stations were installed. ATSB stations may be appropriate for areas with seasonal malaria such as in this Zambia setting, particularly if installed on structures offering a good level of protection such as those with mud walls and thatch roofs. The majority of households in the trial area (over 70%) had thatch roofs 10 . The most common reasons for ATSB station replacement were holes/tears, mold growth, and leaking bait. These results are consistent with data from ATSB intervention monitoring implemented during the main trial in which this sub study was conducted 12 . According to Arnzen et al., the study site has yearly rainfall of approximately 1000mm with temperatures ranging between 18.9 and 30.3 Celsius 10 . Such weather patterns likely supported the significant mold growth on the ATSB stations. In addition, the substantial precipitation likely contributed to bait leakage and subsequent depletion of the ATSB stations. Households in this area usually maintain agricultural plots near their living structures, cultivating maize and cassava 10 . In rural African settings, households often contend with rodent infestations attracted to food stores kept in and around the household. Such infestations can result in significant economic losses for households 23 and may also have contributed to the prevalence of rodent damage (holes and tears) to ATSB stations in this setting. ATSB stations hung on structures with roofs made of cement, iron sheet or wood planks or which were positioned without roof overhang had shorter median survival times. Thatch roofed structures in this area tend to have roof overhangs extending beyond the walls of the structures on all sides, which may have shielded the ATSB stations against rainwater, sun damage, dust, and wind. In the overall trial area, 72% of the dwelling structures were roofed with thatch 10 . In this sample, it was evident that wood plank and cement were not common roof materials in this community. This contributed to fewer observations for these roof types and low precision of ATSB survival time for these types of structures. In general, the protection level at which ATSB stations were installed was largely determined by the architectural style of the structure where they were hung. Stations without protection were typically installed in the center of very high walls, or where the roof had a very small overhang, these tended to be on structures without thatch roofs. The survival period of ATSB stations in these positions were shorter than those with moderate or excellent protection. ATSB stations hung closer to the ground survived better than those hung higher up on the walls. Typically, in this setting, structures with thatch roofing were shorter in height, and had a substantial roof overhang, while structures with high walls generally had limited roof overhangs or the roofline was too high to reach, hence the longer survival of the ATSB stations under shorter structures. This is in contrast to the findings by Diarra et al. (2021) 4 where ATSB stations hung at 1.8m above the ground had limited damages, compared to stations hung at lower levels. Large differences in the survival of ATSB stations were observed among the different clusters. While these differences may be partly attributable to differences in housing style between clusters, it is also likely that other environmental, structural, or socioeconomic differences contributed to variations in longevity of the ATSB stations between clusters. The use of a shared frailty model for the estimation of associations with survival is likely necessary to account for correlation in frailty 22 of individual ATSB stations within study clusters that share characteristics (including environmental exposures, foraging animals, weather elements, community cultural practices); however, additional clustering at the structure and household level was not accounted for in our analysis. Earlier prototypes of the Westham ATSB stations used in Mali (Westham Innovations LTD., Tel Aviv, Israel) 5 maintained their attraction and killing effect while lowering biting rates and reducing entomological inoculation rates while deployed in the field for more than 6 months 2 , 5 . This suggests that subsequent prototypes such as the Sarabi v1.2 ATSB stations that were used in the Zambia trial could remain bio-efficacious and maintain physical integrity longer than the earlier ATSB models, as vector control products continue to be refined and improved. For comparison, the study area in Mali experienced temperature range of 25.1–32.4 Celsius and annual rainfall average of 1098mm 5 , against the approximately 1000mm precipitation in western Zambia 10 . Limitations of this study include the convenience sample used to purposively select the households and structures. The characteristics of housing for bait stations followed in this study may not have been representative of the wider ATSB trial area or of all of western Zambia. The Zambia Malaria Indicator Survey (MIS) 2021, indicated that 18.8% of the surveyed households across Zambia, and 61% across Western Province, had structures that were constructed using rudimentary wall materials of wood with mud plaster, compared to 35.9% in this study site (unpublished MIS 2021). Within the wider trial area, over 70% of households had thatch roofs, but only 47.7% of households in this study had thatch roofs suggesting that the Sarabi v1.2 ATSB stations may survive longer in the trial area than the average for our whole sample. Since ATSB station survival time is associated with structure architecture and installation site characteristics, the overall time to failure for the Sarabi v1.2 ATSB stations in this study should be interpreted with caution. However, the failure times associated with different levels of protection may be useful in combination with information about local architecture in guiding decisions around deployment to maximize the durability of this new tool. Another limitation of this study was right-censoring for some ATSB stations. The ATSB stations were removed from all households after 218 days, the end of the seasonal transmission period and end of the study period, resulting in right-censoring of a substantial number of ATSB stations especially among those deployed under excellent levels of protection. For these stations the estimate of median survival time cannot be made as the median survival time for ATSB stations with excellent protection exceeded the study duration. All that is known is that the ATSB stations hung under excellent level of protection median survival time exceeded 218 days. In addition, the precision of measurement of time to follow-up in this study was somewhat limited by interval censoring since ATSB stations were visited once per month and it was assumed that the failure or censoring occurred at the time of the last observation. ATSB stations that were removed and replaced by the community ATSB monitors were classified as “removed by monitor” as their reason for failure and replacement, without reclassifying their specific reason for removal. It is not known whether the ATSB stations that were “absent on visit” could have been removed by household owners. However, destruction by humans may be limited to adults due to the high position at which the ATSB stations were placed, which was out of reach of children. Additionally, factors such as the suitability of the environment for rodent habitation, temperature and humidity fluctuations may influence the rate at which physical integrity of ATSB stations deteriorates (Kyomuhangi, et al.) 24 . This study was focused on ATSB stations’ physical integrity as defined by criteria that were used during the first large-scale deployment of an ATSB product in a cRCT for malaria control in sub-Saharan Africa. The extent to which these criteria for replacement are associated with loss of ATSB efficacy, bio-efficacy, attractancy or other potential concerns including community acceptability, is not known. It is also important to note that ATSB station deployment in the study setting was not associated with a statistically significant reduction in malaria incidence or prevalence (Ashton et al., in preparation) 25 . CONCLUSION Median survival time was greater than the seasonal deployment period (~ 7 months) for stations that were installed in protected locations, though median survival time for all ATSB stations in the study was approximately 5 months. The majority of Sarabi v1.2 ATSB stations deployed in this setting will remain intact for a seven-month seasonal deployment period if they are installed in locations protected from rain and wind. This includes placement underneath a thatch roof, which was a common housing characteristic in this study setting. These results suggest that future trials of Sarabi v1.2 ATSB stations can better provide a proof of concept by targeting areas with structures that can offer sufficient protection for stations. Further research is needed to understand factors that influence efficacy of ATSB stations and threats to physical integrity in addition to those observed in this study. Declarations Ethics approval and consent to participate Ethical approval was obtained from the National Health Research Ethics Board (NHREB) at the University Teaching Hospital (ethical institution of record) in Zambia (Ref # 1197-2020), the PATH Research Ethics Committee (Ref # 1460046-5), and the Institutional Review Board at Tulane University (Ref # 2019-595). Consent or publication Not applicable Availability of data and materials De-identifi data are available from the corresponding author on reasonable request. Following publication of forthcoming secondary analyses of trial data, the deidentified trial dataset will be posted on a public repository. Competing interests All authors declare that they have no competing interests. Funding This study was funded by IVCC through support from the Bill & Melinda Gates Foundation (grant: INV-007509), the Swiss Agency for Development and Cooperation (SDC) (grant: 81067480) and UK Aid (grant: 30041-105). The findings and conclusions contained within are those of the authors and do not necessarily reflect positions or policies of the Bill & Melinda Gates Foundation, SDC, UK Aid or IVCC. Authors' contributions Designed the study: ML, EO, TE, RA, JY, JM, JC, KS, BH, AH, JE, LS, and TB. Acquisition of the data: MM, MM, KS, and EO. Analyzed the primary data presented in this paper: RK, RA, TE, IK and JY. Wrote the first draft: RK. All other authors reviewed and approved the final document. Acknowledgements This trial was made possible by a committed team of trial staff, data collectors, and community health workers. We also wish to thank the participating communities, health facilities, and district health teams for providing their support. We would like to extend our gratitude to the ATSB Trial Partners Group for their role in trial design and thought partnership. References Bhatt, S.; Weiss, D. J.; Cameron, E.; Bisanzio, D.; Mappin, B.; Dalrymple, U.; Battle, K. E.; Moyes, C. L.; Henry, A.; Eckhoff, P. A.; Wenger, E. A.; Briët, O.; Penny, M. A.; Smith, T. A.; Bennett, A.; Yukich, J.; Eisele, T. P.; Griffin, J. T.; Fergus, C. A.; Lynch, M.; Lindgren, F.; Cohen, J. M.; Murray, C. L. J.; Smith, D. L.; Hay, S. I.; Cibulskis, R. E.; Gething, P. W. The Effect of Malaria Control on Plasmodium Falciparum in Africa between 2000 and 2015. Nature 2015 , 526 (7572), 207–211. https://doi.org/10.1038/nature15535. Mwaanga, G.; Ford, J.; Yukich, J.; Chanda, B.; Ashton, R. A.; Chanda, J.; Munsanje, B.; Muntanga, E.; Mulota, M.; Simuyandi, C.; Mulala, B.; Simubali, L.; Saili, K.; Simulundu, E.; Miller, J.; Hamainza, B.; Orange, E.; Wagman, J.; Mburu, M. M.; Harris, A. F.; Entwistle, J.; Littrell, M. Residual Bioefficacy of Attractive Targeted Sugar Bait Stations Targeting Malaria Vectors during Seasonal Deployment in Western Province of Zambia. Malar. J. 2024 , 23 (1), 169. https://doi.org/10.1186/s12936-024-04990-3. Fraser, K. J.; Mwandigha, L.; Traore, S. F.; Traore, M. M.; Doumbia, S.; Junnila, A.; Revay, E.; Beier, J. C.; Marshall, J. M.; Ghani, A. C.; Müller, G. Estimating the Potential Impact of Attractive Targeted Sugar Baits (ATSBs) as a New Vector Control Tool for Plasmodium Falciparum Malaria. Malar. J. 2021 , 20 (1), 151. https://doi.org/10.1186/s12936-021-03684-4. Diarra, R. A.; Traore, M. M.; Junnila, A.; Traore, S. F.; Doumbia, S.; Revay, E. E.; Kravchenko, V. D.; Schlein, Y.; Arheart, K. L.; Gergely, P.; Hausmann, A.; Beck, R.; Xue, R.-D.; Prozorov, A. M.; Kone, A. S.; Majambere, S.; Vontas, J.; Beier, J. C.; Müller, G. C. Testing Configurations of Attractive Toxic Sugar Bait (ATSB) Stations in Mali, West Africa, for Improving the Control of Malaria Parasite Transmission by Vector Mosquitoes and Minimizing Their Effect on Non-Target Insects. Malar. J. 2021 , 20 (1), 184. https://doi.org/10.1186/s12936-021-03704-3. Traore, M. M.; Junnila, A.; Traore, S. F.; Doumbia, S.; Revay, E. E.; Kravchenko, V. D.; Schlein, Y.; Arheart, K. L.; Gergely, P.; Xue, R.-D.; Hausmann, A.; Beck, R.; Prozorov, A.; Diarra, R. A.; Kone, A. S.; Majambere, S.; Bradley, J.; Vontas, J.; Beier, J. C.; Müller, G. C. Large-Scale Field Trial of Attractive Toxic Sugar Baits (ATSB) for the Control of Malaria Vector Mosquitoes in Mali, West Africa. Malar. J. 2020 , 19 (1), 72. https://doi.org/10.1186/s12936-020-3132-0. Briet, O.; Koenker, H.; Norris, L.; Wiegand, R.; Vanden Eng, J.; Thackeray, A.; Williamson, J.; Gimnig, J. E.; Fortes, F.; Akogbeto, M.; Yadouleton, A. W.; Ombok, M.; Bayoh, M. N.; Mzilahowa, T.; Abílio, A. P.; Mabunda, S.; Cuamba, N.; Diouf, E.; Konaté, L.; Hamainza, B.; Katebe-Sakala, C.; Ponce de León, G.; Asamoa, K.; Wolkon, A.; Smith, S. C.; Swamidoss, I.; Green, M.; Gueye, S.; Mihigo, J.; Morgan, J.; Dotson, E.; Craig, A. S.; Tan, K. R.; Wirtz, R. A.; Smith, T. Attrition, Physical Integrity and Insecticidal Activity of Long-Lasting Insecticidal Nets in Sub-Saharan Africa and Modelling of Their Impact on Vectorial Capacity. Malar. J. 2020 , 19 (1), 310. https://doi.org/10.1186/s12936-020-03383-6. Abílio, A. P.; Obi, E.; Koenker, H.; Babalola, S.; Saifodine, A.; Zulliger, R.; Swamidoss, I.; Ponce de Leon, G.; Alfai, E.; Blaufuss, S.; Olapeju, B.; Harig, H.; Kilian, A. Monitoring the Durability of the Long-Lasting Insecticidal Nets MAGNet and Royal Sentry in Three Ecological Zones of Mozambique. Malar. J. 2020 , 19 (1), 209. https://doi.org/10.1186/s12936-020-03282-w. Hiruy, H. N.; Irish, S. R.; Abdelmenan, S.; Wuletaw, Y.; Zewde, A.; Woyessa, A.; Haile, M.; Chibsa, S.; Lorenz, L.; Worku, A.; Yukich, J.; Berhane, Y.; Keating, J. Durability of Long-Lasting Insecticidal Nets (LLINs) in Ethiopia. Malar. J. 2023 , 22 (1), 109. https://doi.org/10.1186/s12936-023-04540-3. Yewhalaw, D.; Simma, E. A.; Zemene, E.; Zeleke, K.; Degefa, T. Residual Efficacy of SumiShield TM 50WG for Indoor Residual Spraying in Ethiopia. Malar. J. 2022 , 21 (1), 364. https://doi.org/10.1186/s12936-022-04395-0. Arnzen, A.; Wagman, J.; Chishya, C.; Orange, E.; Eisele, T. P.; Yukich, J.; Ashton, R. A.; Chanda, J.; Sakala, J.; Chanda, B.; Muyabe, R.; Kaniki, T.; Mwenya, M.; Mwaanga, G.; Eaton, W. T.; Mancuso, B.; Mungo, A.; Mburu, M. M.; Bubala, N.; Hagwamuna, A.; Simulundu, E.; Saili, K.; Miller, J. M.; Silumbe, K.; Hamainza, B.; Ngulube, W.; Moonga, H.; Chirwa, J.; Burkot, T. R.; Slutsker, L.; Littrell, M. Characteristics of the Western Province, Zambia, Trial Site for Evaluation of Attractive Targeted Sugar Baits for Malaria Vector Control. Malar. J. 2024 , 23 , 153. https://doi.org/10.1186/s12936-024-04985-0. Attractive Targeted Sugar Bait Phase III Trial Group. Attractive Targeted Sugar Bait Phase III Trials in Kenya, Mali, and Zambia. Trials 2022 , 23 (1), 640. https://doi.org/10.1186/s13063-022-06555-8. Orange, E.; Kyomuhangi, I.; Masuzyo, M.; Mwenya, M.; Mambo, P.; Saili, K.; Chishya, C.; Chanda, J.; Ashton, R.; Eisele, T.; Yukich, J.; Miller, J.; Silumbe, K.; Hamainza, B.; Wagman, J.; Arnzen, A.; Harris, A.; Entwistle, J.; Slutsker, L.; Littrell, M. Deployment of Attractive Targeted Sugar Baits in Western Zambia: Installation, Monitoring, Removal, and Disposal Procedures during a Phase III Cluster Randomized Control Trial. ; 2024. https://doi.org/10.21203/rs.3.rs-4224677/v1. Census-of-Population-and-Housing-Preliminary.Pdf. https://www.zamstats.gov.zm/wp-content/uploads/2023/05/2022-Census-of-Population-and-Housing-Preliminary.pdf (accessed 2024-01-13). Lynn, R. C.; Duquette, R. A. 6 - Antiparasitic Drugs. In Georgis’ Parasitology for Veterinarians (Eleventh Edition) ; Bowman, D. D., Ed.; W.B. Saunders: St. Louis (MO), 2021; pp 286–348. https://doi.org/10.1016/B978-0-323-54396-5.00015-5. Dinotefuran - an overview | ScienceDirect Topics . https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/dinotefuran (accessed 2024-03-19). Brookmeyer, R.; Crowley, J. A Confidence Interval for the Median Survival Time. Biometrics 1982 , 38 (1), 29–41. https://doi.org/10.2307/2530286. R: The R Project for Statistical Computing . https://www.r-project.org/ (accessed 2024-06-16). Therneau, T. M.; until 2009), T. L. (original S.->R port and R. maintainer; Elizabeth, A.; Cynthia, C. Survival: Survival Analysis, 2023. https://cran.r-project.org/web/packages/survival/index.html (accessed 2024-02-06). Kassambara, A.; Kosinski, M.; Biecek, P.; Fabian, S. Survminer: Drawing Survival Curves Using “Ggplot2,” 2021. https://cran.r-project.org/web/packages/survminer/index.html (accessed 2024-02-06). Rondeau, V.; Gonzalez, J. R.; Mazroui, Y.; Mauguen, A.; Diakite, A.; Laurent, A.; Lopez, M.; Krol, A.; Sofeu, C. L.; Dumerc, J.; Rustand, D.; Chauvet, J.; Coent, Q. L.; Pierlot, R.; Hill, D.; Burkardt, J.; Genz, A.; Rego, A. J. Frailtypack: Shared, Joint (Generalized) Frailty Models; Surrogate Endpoints, 2023. https://cran.r-project.org/web/packages/frailtypack/index.html (accessed 2024-02-06). Therneau, T. M. Coxme: Mixed Effects Cox Models, 2024. https://cran.r-project.org/web/packages/coxme/index.html (accessed 2024-05-12). Kleinbaum, D. G.; Klein, M. Survival Analysis: A Self-Learning Text , Third edition, corrected publication.; Statistics for biology and health; Springer: New York Dordrecht Heidelberg London, 2020. Donga, T. K.; Bosma, L.; Gawa, N.; Meheretu, Y. Rodents in Agriculture and Public Health in Malawi: Farmers’ Knowledge, Attitudes, and Practices. Front. Agron. 2022 , 4 . https://doi.org/10.3389/fagro.2022.936908. Kyomuhangi, I.; Yukich, J.; Saili, K.; Orange, E.; Masuzyo, M. H.; Mwenya, M.; Mambo, P.; Hamainza, B.; Wagman, J.; Miller, J.; Chanda, J.; Silumbe, K.; Littrell, M.; Eisele, T. P.; Ashton, R. A. Evaluating Trends in Damage to Attractive Targeted Sugar Baits Deployed during the Second Year of a Two-Year Phase III Trial in Western Zambia. June 6, 2024. https://doi.org/10.21203/rs.3.rs-4523449/v1. Ashton R.A.; Saili K.; Chishya C.; Banda H.; Arnzen A.; Orange E.; Chitoshi C.; Efficacy of Attractive Targeted Sugar Bait stations against malaria in Western Province Zambia: epidemiological findings from a two-arm cluster randomized Phase III trial. The Lancet Global Health (2024) Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4670314","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":328761111,"identity":"d30e2a26-3c3b-4d4b-9205-c0748f5b6782","order_by":0,"name":"Refilwe Y. 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However, recently, the reduction in malaria cases has stalled, highlighting the need for new vector control tools for better control and ultimately elimination and eradication of malaria.\u003c/p\u003e \u003cp\u003ePlant sugars serve as an important energy source for both male and female mosquitoes. This can in theory be targeted by providing artificial sugar source as an attractant to lure, and if combined with an insecticide, to kill mosquitoes. This approach to vector control has been called Attractive Targeted Sugar Bait (ATSB). ATSB stations are a promising innovation, and a potential addition to existing vector control tools\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. ATSB stations thus differ from the existing recommended vector control methods that target indoor human blood feeding (Insecticide Treated Nets) and resting behaviors (Indoor Residual Spraying, IRS). In 2017, ATSB stations were shown to reduce \u003cem\u003eAnopheles\u003c/em\u003e mosquito densities in field settings in Mali\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. A phase III cluster randomized control trial (cRCT) was conducted in Western Zambia to investigate the efficacy of the Sarabi v.1.2 ATSB stations (manufactured by Westham Ltd., Hod-Hasharon, Israel) in reducing malaria incidence.\u003c/p\u003e \u003cp\u003eThe sustained effectiveness of many vector control products, when deployed, depends on their physical integrity and ultimately their durability (ability to resist wear and last over time). For example, Long-Lasting Insecticidal Net (LLIN) durability has been previously defined to include persistent insecticidal effectiveness, physical durability and attrition\u003csup\u003e\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Further, Briet et al. (2020) indicate that \u0026lsquo;LLIN survivorship is an important precondition for use\u0026rsquo;\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. This means that the durability of LLINs is a critical requirement for their utilization.\u003c/p\u003e \u003cp\u003eIn the context of IRS, insecticide residual efficacy is used to characterize intervention durability or persistence in the field\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Due to the novelty of the Westham Sarabi v.1.2 ATSB stations, there is limited understanding of their durability, and their bio-efficacy under different conditions. In a recent study by Mwaanga et al. (2024)\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, bio-efficacy of ATSB stations was measured for ATSB tools which remained physically intact during field deployment. The results indicated that ATSB stations which remain physically intact can also remain bio-efficacious following deployment for at least seven months in the field. However, a gap remains in understanding the physical durability and survival of the ATSB product under deployment conditions, given that there is no information on how long ATSB stations can maintain high levels of physical integrity in the field.\u003c/p\u003e \u003cp\u003eThis study seeks to ascertain the duration of physical integrity and attrition of the Westham Sarabi v1.2 ATSB stations used during the trial, an important component of the overall durability of ATSB. Factors that include the duration of physical integrity, bio-efficacy and attractancy as well as attrition are relevant in this context. The aim of this study is to assess the median time that the ATSB stations remain deployed in the field before replacement due to deterioration in physical integrity, and do not go missing, which we describe as the survival time.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eThe study defines physical integrity of the ATSB station as remaining undamaged, intact, or without structural defect. This good condition is defined as not meeting pre-defined criteria for replacement due to holes/tears, leaks, mold, dirt, or depletion.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy site\u003c/h2\u003e \u003cp\u003eThe cRCT trial was conducted in Kaoma, Luampa, and Nkeyema districts, in Western Province, Zambia from November 2021 to June 2022 and November 2022 to June 2023. The study site is described by Arnzen et al.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e, details of the trial design are reported by Eisele et al. \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e, and the ATSB intervention is described in detail by Orange et al.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. The three trial districts have a combined population of 246,785 (2022 population census)\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The climate is tropical with a rainy season from approximately December through March\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e, which supports arable and pastoral agricultural activities. The rainy season is followed by a peak in malaria transmission from April to May.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eATSB stations\u003c/h2\u003e \u003cp\u003eThe ATSB Sarabi v.1.2 bait station (Westham Ltd., Hod-Hasharon, Israel) measures slightly over 24cm X 30.5cm. Each bait station has 16 cells filled with 72g of date syrup-based bait, which acts as both the attractant and sugar source, dinotefuran (0.11% w/w) the active ingredient, and Bitrex\u0026reg; (Johnson Matthey), a bittering agent to deter ingestion by humans. Dinotefuran, an ingestion toxicant, is a furanicotinyl (neo-nicotinoid) insecticide, which occupies and activates the nicotinic acetylcholine receptors of the mosquitoes\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. The toxicant binds permanently to the insects\u0026rsquo; nicotinic receptors and mimics the effects of acetylcholine, resulting in constant nerve stimulation, tremors, and eventually death\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. ATSB station contents are contained between a white plastic backing and a black perforated membrane that allows the mosquito proboscis to penetrate and ingest the bait, while reducing the ability of non-target organisms to access the bait, as well as evaporation of volatile components in the bait including water. The white plastic backing and membrane are fused together in the 1cm spaces between the cells. Further details of the ATSB station used in this trial are reported in Orange et al.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eATSB station installation campaigns\u003c/h2\u003e \u003cp\u003eATSB stations were installed on study households as part of the second year of the cRCT in November 2022. Eligible structures that received ATSB stations were defined as those with a complete roof, at least three complete exterior walls, wall height measuring one meter or more, and structures not under construction (primarily sleeping structures and multi-use residential structures). Structures that were identified as shops, schools, churches, tobacco sheds, animal kraals, toilets, bathing shelters, and food storage shelters were not eligible for ATSB station installation. Two ATSB stations were installed on each eligible structure by trained community members (ATSB Monitors). ATSB stations were typically hung on opposite exterior walls of a structure unless adjacent walls offered better protection from rain, sun, and wind. ATSB stations were hung on walls using bamboo sticks inserted through holes on the top and bottom frames of the ATSB station. Strings or wires were wound around the bamboo sticks to attach the ATSB stations to anchored nails on the walls of the structures. Further details of ATSB station installation are available in Orange et al.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and data collection procedures\u003c/h2\u003e \u003cp\u003eA prospective open cohort of ATSB was nested within the routine ATSB monitoring procedures of the ATSB trial. Selected ATSB stations installed during the trial installation campaign were enrolled in this study on a first visit by the research team shortly after placement on structures in late November to early December 2022. As a rolling cohort, additional ATSB stations installed and enrolled in the cohort either on new structures, or as replacements for damaged stations were also enrolled into this study.\u003c/p\u003e \u003cp\u003eTwenty of the 35 intervention arm clusters were purposively selected for inclusion in this study. Ten or eleven households were purposively selected from each of the 20 clusters. The enrollment visit occurred approximately two weeks after ATSB installation. On the enrollment visit (late November or early December 2022), the research team created sketch maps of the selected households, documented all the structures in each household, and recorded details of ATSB stations already present on structures from the ATSB installation campaign. Each ATSB station had a unique QR code which had been printed during manufacturing. Monthly visits were made to all enrolled households and structures. At each visit, presence or absence of each ATSB station was confirmed and location verified. ATSB stations were assessed according to pre-defined damage criteria for replacement including holes/tears, leaks, mold, dirt, and depletion \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Presence of mold that led to replacement was defined as fuzzy mold growth more than the size of rubber/eraser end of a pencil or layer of mold that covered at least half of the ATSB station surface. Tears/holes were defined as one or more cells being fully open. Dirt that warranted replacement was described as having at least eight cells covered in dirt. ATSB trial staff also palpated the ATSB stations to check if each of the 16 cells on each station were depleted of bait or not. ATSB stations that warranted replacement had eight or more cells flat or empty when checked with a gloved hand. A photograph of the ATSB station was also taken as evidence of its presence and condition. ATSB stations meeting the replacement criteria were replaced with a new station, and the QR code of the newly installed ATSB station recorded and enrolled into the study.\u003c/p\u003e \u003cp\u003eDuring each study visit, location and characteristics of each ATSB station installation site were documented. These included the distance between the lower end of the ATSB station and the ground, the distance between the upper portion of the ATSB station and the roof (at the point where the roof and the exterior wall meet), as well as the length of the roof overhang (distance perpendicular to the outside wall). Information on the material used for construction of the structure\u0026rsquo;s wall and roof was also documented.\u003c/p\u003e \u003cp\u003eIf an enrolled structure was demolished, burned, or collapsed, this was documented, and no further visits were made to it. If a new ATSB station-eligible structure was identified at an enrolled household during a study visit, the structure was enrolled. The existing ATSB stations would then be registered, or ATSB stations installed and registered if not already present. This study was embedded in the ATSB main cRCT monitoring program; hence the ATSB stations were routinely assessed by ATSB monitors. This monitoring occurred once every two months, or sooner if damage was reported by the household. It was possible for ATSB stations to be visited more than once a month by the ATSB monitors as part of routine monitoring for the trial, and by the research team for the physical durability study. Routine monitoring visits used the same replacement criteria as this study to remove, and replace damaged or lost bait stations.\u003c/p\u003e \u003cp\u003eObservations of ATSB stations were recorded using an android-based digital data collection tool (Commcare, Diamgi Inc., Cambridge MA, USA).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eSample size\u003c/h2\u003e \u003cp\u003eThe sample size was calculated following the Brookmeyer and Crowley (1982) method\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. The median survival of an ATSB station was assumed to be 3 months, and the sample size was planned to allow for this to be estimated with a 95% Confidence Interval of 2.3\u0026ndash;4.1 months. It was anticipated that this level of precision could be achieved if a minimum of two ATSB stations were installed and followed at each selected household, and a minimum of 10 households in 10 clusters were included. This resulted in a minimum of 100 households, and 200 ATSB stations, and potentially monitoring of more than 300 ATSB stations (including replacements) being followed for six months. Field logistics and funding permitted expansion of the study from 10 to 20 clusters, but retained a target enrolment of at least 10 households per cluster in theory allowing for a more precise estimation of the study outcome.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eData analysis was conducted using R programming language version 4.2.2\u003csup\u003e17\u003c/sup\u003e and packages \u0026lsquo;survival\u0026rsquo;\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, \u0026lsquo;survminer\u0026rsquo;\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e, \u0026lsquo;frailtypack\u0026rsquo;\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, and \u0026lsquo;coxme\u0026rsquo;\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eOutcomes and other measures\u003c/h3\u003e\n\u003cp\u003eThe main endpoint of the study was ATSB station meeting criteria for replacement or having been removed. The outcome event was defined as occurring when the ATSB station met the replacement criteria on the monthly durability study visit or was not found where it was expected (either replaced by routine monitoring process or lost). The ATSB stations that had not experienced an outcome event continued to be followed and monitored in the subsequent visits to the end of the study or when lost to follow up for other reasons, such as destruction or removal of the structure on which the station had been placed. Stations which did not experience an event were considered as right censored at their last visit. Right censorship occurs when the study ends or when a subject, in this case an ATSB station is lost to follow up. The true survival time is incomplete at the right side of the follow-up period\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTime to event was measured in days until failure/event occurred or censoring. This was defined as the number of days between the ATSB station being enrolled in the study and the date a failure/event was recorded (ATSB station was found damaged, removed from its location or other reasons that met the pre-determined replacement criteria) or the ATSB station was censored.\u003c/p\u003e \u003cp\u003eDetails of ATSB-station installation location were used to generate an indicator of protection level with three classes. \u0026ldquo;Excellent protection\u0026rdquo; was defined as ATSB stations that were either reported as \u0026ldquo;tucked under the roof overhang\u0026rdquo; on observation or where the ratio of measured roof overhang to distance from roof to ATSB stations was greater than one. \u0026ldquo;Some/moderate protection\u0026rdquo; was defined as ATSB stations that were reported as either being placed at level with the edge of the roof, or where the ratio of measured roof overhang to measured distance from roof to ATSB station was 0.5 or larger but less than one. \u0026ldquo;No protection\u0026rdquo; was defined as ATSB stations where the ratio of roof overhang size to distance from roof to ATSB station was \u0026lt;\u0026thinsp;0.5. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows photos of stations installed on study buildings as visual examples of these protection levels. The study also considered the height of ATSB station above the ground. The measurements were categorized into four groups (\u0026lt;\u0026thinsp;100cm, \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;100-150cm, \u0026gt;\u0026thinsp;150-200cm and \u0026gt;\u0026thinsp;200cm between the ATSB station and the ground).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eKaplan-Meier survival estimates were used to calculate the overall median survival time, and median survival time stratified by protection level. Stratified Cox-Proportional Hazard models were used to examine differences in survival by different roof materials, wall placement position, protection level and different clusters, using shared frailty methods to account for the clustering of ATSB stations within study clusters from the overall ATSB cRCT.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe study enrolled 304 eligible structures in 206 households for monthly visits. A total of 1,107 ATSB stations across 20 clusters, with a range of 32\u0026ndash;139 ATSB stations per cluster were analyzed. For monitoring purposes 5,696 ATSB station-visits were made from November 2022 to June 2023 for this study (not including visits made by ATSB monitors). The maximum duration from the time of enrollment in the study to a final ATSB station-visit was 218 days.\u003c/p\u003e \u003cp\u003eSixteen structures were excluded after enrollment as they were subsequently considered not eligible because they were no longer being used as sleeping structures, or because the structure had collapsed or burned after data collection had begun. During the study, 17 newly eligible structures were enrolled at participating households, with 34 new ATSB stations installed on these structures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of structure characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWall type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;304 (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood with mud plaster\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e109 (35.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement block\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e72 (23.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMud brick, covered*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (10.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMud brick, uncovered\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68 (22.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood plank\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (4.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThatch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (3.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRoof type\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIron Sheet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e152 (50)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThatch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e145 (47.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (1.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood plank\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (0.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e*Mud bricks are covered with mud or cement plaster\u003c/h2\u003e \u003cp\u003eAmong the enrolled structures, 35.9% (109/304) had wood walls with mud plaster, and half of all structures were roofed with iron sheets (152/304, 50%, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e indicates the distribution of all ATSB stations included in the study at any time, according to the wall type, protection level and roof type of the structures they were installed on.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eStructure characteristics of installed ATSB stations\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eProtection level of installed ATSB\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExcellent protection (N\u0026thinsp;=\u0026thinsp;621)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate protection\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;292)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003cp\u003eprotection (N\u0026thinsp;=\u0026thinsp;194)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHung on wall type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood with mud plaster\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e319\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement block\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e115\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e126\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMud brick, covered*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMud brick, uncovered\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e174\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood plank\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThatch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHung under roof type\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIron Sheet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e281\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e173\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThatch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e521\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWood plank\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e*Mud bricks are covered with mud or cement plaster\u003c/h2\u003e \u003cp\u003eOverall, 48.6% of enrolled ATSB stations met criteria for failure and reason for replacement during the study period (up to 218 days). The median time (of ATSB stations) from enrollment to replacement or loss by cluster ranged from 35 days to beyond the 218 days of the study period. Nine of the 20 clusters (45%) had ATSB stations with median lifetime greater than the 218-days, indicating that in those clusters more than half of the ATSB stations enrolled at the start of the study remained hanging and intact at the end of the study period.\u003c/p\u003e \u003cp\u003eThe most common reasons for ATSB station replacement/event were holes/tears (24.3%), followed by mold (21.6%) and leaking (19.3%) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Stations with two or more categories of damage contributed 2.6% of the observed reasons for replacement. 108 (20.1%) enrolled ATSB stations were replaced by trained community members during routine monitoring visits, between the scheduled visits of this study. Relatively few ATSB stations (5.6%) were missing or lost to follow up.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eReasons for ATSB replacement\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eATSBs N\u0026thinsp;=\u0026thinsp;538 (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: torn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e131 (24.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: mold\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e116 (21.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: leak\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e104 (19.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: depleted\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30 (5.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: dirty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5 (0.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDamaged: more than one category\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14 (2.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbsent/missing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30 (5.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRemoved by community monitor*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e108 (20.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e* \u003cb\u003eSeparate from the research team in this study, ATSB monitors visited bait stations to perform assessments of bait station condition and to remove and replace damaged bait stations during routine monitoring for the trial.\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA total of 569 ATSB stations were right-censored. This included ATSB stations not meeting replacement criteria at the final visit and those right censored during the course of the study (including those hung on structures that later collapsed, burned or ineligible). The median survival for all ATSB stations in this study was 149 days (95% CI: 133, 164) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), approximately 5 months. ATSB stations hung on structures with thatch roofing had the longest median survival time at \u0026gt;\u0026thinsp;218 days. ATSB station median survival differed according to protection level of the installation site, with median survival of ATSB stations in locations with \u0026ldquo;excellent protection\u0026rdquo; of \u0026gt;\u0026thinsp;218 days, while median survival time in sites with \u0026ldquo;some protection\u0026rdquo; and \u0026ldquo;no protection\u0026rdquo; were 124 days and 90 days, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Large differences in median survival time were also observed between different clusters (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe Cox-Proportional hazards model indicated that ATSB stations installed in locations with \u0026ldquo;excellent protection\u0026rdquo; had a longer survival time than those in locations with \u0026ldquo;no protection\u0026rdquo; (hazard ratio (HR)\u0026thinsp;=\u0026thinsp;0.36, 95% CI 0.25\u0026ndash;0.49, Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). ATSB stations in locations with \u0026ldquo;moderate protection\u0026rdquo; also had longer survival times compared to those with \u0026ldquo;no protection\u0026rdquo; (HR 0.62, 95% CI 0.47\u0026ndash;0.82). Thatch roof was also associated with improved ATSB station survival (HR 0.37, 95% CI 0.26\u0026ndash;0.47) compared to ATSB stations on structures with iron sheet roofs.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDeterminants of ATSB survival, estimated by univariate Cox-proportional hazards models with shared frailty for cluster\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUnadjusted hazard ratio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eProtection level\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference No protection (n\u0026thinsp;=\u0026thinsp;194)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerate protection (n\u0026thinsp;=\u0026thinsp;292)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.47, 0.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExcellent protection (n\u0026thinsp;=\u0026thinsp;621)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.25, 0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrailty (cluster)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRoof material\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference iron sheet (n\u0026thinsp;=\u0026thinsp;554)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCement or wood plank (n\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.79, 2.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThatch (n\u0026thinsp;=\u0026thinsp;527)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.26, 0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrailty (cluster)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDistance of ATSB to ground\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReference\u0026thinsp;\u0026lt;\u0026thinsp;100cm (n\u0026thinsp;=\u0026thinsp;167)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;200cm (n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.13, 13.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e151-200cm (n\u0026thinsp;=\u0026thinsp;296)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.32, 2.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e100-150cm (n\u0026thinsp;=\u0026thinsp;633)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.04, 1.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrailty (cluster)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eShorter distance between the ATSB station and the ground was associated with improved longevity of the ATSB stations. The univariate Cox-Proportional Hazard model (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) indicated that ATSB stations hung over 200cm above the ground were more likely to be lost or damaged compared to those ATSB stations placed 100cm or less above the ground (HR 5.28, 95% CI 2.13\u0026ndash;13.12). ATSB stations installed at heights of 100-150cm or 151-200cm above the ground also had reduced survival compared to those placed at 1 meter or lower (HR 1.35 and 1.84, respectively).\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis is the first study to estimate the survival time of an ATSB product during seasonal deployment to control malaria in Africa. ATSB stations installed with excellent protection had median survival times\u0026thinsp;\u0026gt;\u0026thinsp;218 days, which is longer than the seasonal deployment period in this setting. The overall median survival time for ATSB stations was 149 days, meaning 50% of the ATSB stations were still hanging and in good condition after approximately 5 months. For comparison, the seasonal ATSB deployment period in this Zambian setting was approximately seven months (deployment in November and removal in June). There were large differences in median survival times by cluster, and according to the characteristics of the structure and location on the structure where ATSB stations were installed.\u003c/p\u003e \u003cp\u003eATSB stations may be appropriate for areas with seasonal malaria such as in this Zambia setting, particularly if installed on structures offering a good level of protection such as those with mud walls and thatch roofs. The majority of households in the trial area (over 70%) had thatch roofs\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe most common reasons for ATSB station replacement were holes/tears, mold growth, and leaking bait. These results are consistent with data from ATSB intervention monitoring implemented during the main trial in which this sub study was conducted \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. According to Arnzen et al., the study site has yearly rainfall of approximately 1000mm with temperatures ranging between 18.9 and 30.3 Celsius\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Such weather patterns likely supported the significant mold growth on the ATSB stations. In addition, the substantial precipitation likely contributed to bait leakage and subsequent depletion of the ATSB stations.\u003c/p\u003e \u003cp\u003eHouseholds in this area usually maintain agricultural plots near their living structures, cultivating maize and cassava\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In rural African settings, households often contend with rodent infestations attracted to food stores kept in and around the household. Such infestations can result in significant economic losses for households\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e and may also have contributed to the prevalence of rodent damage (holes and tears) to ATSB stations in this setting.\u003c/p\u003e \u003cp\u003eATSB stations hung on structures with roofs made of cement, iron sheet or wood planks or which were positioned without roof overhang had shorter median survival times. Thatch roofed structures in this area tend to have roof overhangs extending beyond the walls of the structures on all sides, which may have shielded the ATSB stations against rainwater, sun damage, dust, and wind. In the overall trial area, 72% of the dwelling structures were roofed with thatch\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In this sample, it was evident that wood plank and cement were not common roof materials in this community. This contributed to fewer observations for these roof types and low precision of ATSB survival time for these types of structures.\u003c/p\u003e \u003cp\u003eIn general, the protection level at which ATSB stations were installed was largely determined by the architectural style of the structure where they were hung. Stations without protection were typically installed in the center of very high walls, or where the roof had a very small overhang, these tended to be on structures without thatch roofs. The survival period of ATSB stations in these positions were shorter than those with moderate or excellent protection. ATSB stations hung closer to the ground survived better than those hung higher up on the walls. Typically, in this setting, structures with thatch roofing were shorter in height, and had a substantial roof overhang, while structures with high walls generally had limited roof overhangs or the roofline was too high to reach, hence the longer survival of the ATSB stations under shorter structures. This is in contrast to the findings by Diarra et al. (2021)\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e where ATSB stations hung at 1.8m above the ground had limited damages, compared to stations hung at lower levels.\u003c/p\u003e \u003cp\u003eLarge differences in the survival of ATSB stations were observed among the different clusters. While these differences may be partly attributable to differences in housing style between clusters, it is also likely that other environmental, structural, or socioeconomic differences contributed to variations in longevity of the ATSB stations between clusters. The use of a shared frailty model for the estimation of associations with survival is likely necessary to account for correlation in frailty\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e of individual ATSB stations within study clusters that share characteristics (including environmental exposures, foraging animals, weather elements, community cultural practices); however, additional clustering at the structure and household level was not accounted for in our analysis.\u003c/p\u003e \u003cp\u003eEarlier prototypes of the Westham ATSB stations used in Mali (Westham Innovations LTD., Tel Aviv, Israel)\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e maintained their attraction and killing effect while lowering biting rates and reducing entomological inoculation rates while deployed in the field for more than 6 months\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. This suggests that subsequent prototypes such as the Sarabi v1.2 ATSB stations that were used in the Zambia trial could remain bio-efficacious and maintain physical integrity longer than the earlier ATSB models, as vector control products continue to be refined and improved. For comparison, the study area in Mali experienced temperature range of 25.1\u0026ndash;32.4 Celsius and annual rainfall average of 1098mm\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e, against the approximately 1000mm precipitation in western Zambia\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eLimitations of this study include the convenience sample used to purposively select the households and structures. The characteristics of housing for bait stations followed in this study may not have been representative of the wider ATSB trial area or of all of western Zambia. The Zambia Malaria Indicator Survey (MIS) 2021, indicated that 18.8% of the surveyed households across Zambia, and 61% across Western Province, had structures that were constructed using rudimentary wall materials of wood with mud plaster, compared to 35.9% in this study site (unpublished MIS 2021). Within the wider trial area, over 70% of households had thatch roofs, but only 47.7% of households in this study had thatch roofs suggesting that the Sarabi v1.2 ATSB stations may survive longer in the trial area than the average for our whole sample. Since ATSB station survival time is associated with structure architecture and installation site characteristics, the overall time to failure for the Sarabi v1.2 ATSB stations in this study should be interpreted with caution. However, the failure times associated with different levels of protection may be useful in combination with information about local architecture in guiding decisions around deployment to maximize the durability of this new tool. Another limitation of this study was right-censoring for some ATSB stations. The ATSB stations were removed from all households after 218 days, the end of the seasonal transmission period and end of the study period, resulting in right-censoring of a substantial number of ATSB stations especially among those deployed under excellent levels of protection. For these stations the estimate of median survival time cannot be made as the median survival time for ATSB stations with excellent protection exceeded the study duration. All that is known is that the ATSB stations hung under excellent level of protection median survival time exceeded 218 days. In addition, the precision of measurement of time to follow-up in this study was somewhat limited by interval censoring since ATSB stations were visited once per month and it was assumed that the failure or censoring occurred at the time of the last observation.\u003c/p\u003e \u003cp\u003eATSB stations that were removed and replaced by the community ATSB monitors were classified as \u0026ldquo;removed by monitor\u0026rdquo; as their reason for failure and replacement, without reclassifying their specific reason for removal. It is not known whether the ATSB stations that were \u0026ldquo;absent on visit\u0026rdquo; could have been removed by household owners. However, destruction by humans may be limited to adults due to the high position at which the ATSB stations were placed, which was out of reach of children. Additionally, factors such as the suitability of the environment for rodent habitation, temperature and humidity fluctuations may influence the rate at which physical integrity of ATSB stations deteriorates (Kyomuhangi, et al.)\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThis study was focused on ATSB stations\u0026rsquo; physical integrity as defined by criteria that were used during the first large-scale deployment of an ATSB product in a cRCT for malaria control in sub-Saharan Africa. The extent to which these criteria for replacement are associated with loss of ATSB efficacy, bio-efficacy, attractancy or other potential concerns including community acceptability, is not known. It is also important to note that ATSB station deployment in the study setting was not associated with a statistically significant reduction in malaria incidence or prevalence (Ashton et al., in preparation)\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eMedian survival time was greater than the seasonal deployment period (~\u0026thinsp;7 months) for stations that were installed in protected locations, though median survival time for all ATSB stations in the study was approximately 5 months. The majority of Sarabi v1.2 ATSB stations deployed in this setting will remain intact for a seven-month seasonal deployment period if they are installed in locations protected from rain and wind. This includes placement underneath a thatch roof, which was a common housing characteristic in this study setting. These results suggest that future trials of Sarabi v1.2 ATSB stations can better provide a proof of concept by targeting areas with structures that can offer sufficient protection for stations. Further research is needed to understand factors that influence efficacy of ATSB stations and threats to physical integrity in addition to those observed in this study.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cu\u003eEthics approval and consent to participate\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval was obtained from the National Health Research Ethics Board (NHREB) at the University Teaching Hospital (ethical institution of record) in Zambia (Ref # 1197-2020), the PATH Research Ethics Committee (Ref # 1460046-5), and the Institutional Review Board at Tulane University (Ref # 2019-595).\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eConsent or publication\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eAvailability of data and materials\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eDe-identifi data are available from the corresponding author on reasonable request. Following publication of forthcoming secondary analyses of trial data, the deidentified trial dataset will be posted on a public repository.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eCompeting interests\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare that they have no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eFunding\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded by IVCC through support from the Bill \u0026amp; Melinda Gates Foundation (grant: INV-007509), the Swiss Agency for Development and Cooperation (SDC) (grant: 81067480) and UK Aid (grant: 30041-105). The findings and conclusions contained within are those of the authors and do not necessarily reflect positions or policies of the Bill \u0026amp; Melinda Gates Foundation, SDC, UK Aid or IVCC.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eAuthors\u0026apos; contributions\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eDesigned the study: ML, EO, TE, RA, JY, JM, JC, KS, BH, AH, JE, LS, and TB. Acquisition of the data: MM, MM, KS, and EO. Analyzed the primary data presented in this paper: RK, RA, TE, IK and JY. Wrote the first draft: RK. All other authors reviewed and approved the final document.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eAcknowledgements\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eThis trial was made possible by a committed team of trial staff, data collectors, and community health workers. We also wish to thank the participating communities, health facilities, and district health teams for providing their support. We would like to extend our gratitude to the ATSB Trial Partners Group for their role in trial design and thought partnership.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBhatt, S.; Weiss, D. J.; Cameron, E.; Bisanzio, D.; Mappin, B.; Dalrymple, U.; Battle, K. E.; Moyes, C. L.; Henry, A.; Eckhoff, P. A.; Wenger, E. A.; Bri\u0026euml;t, O.; Penny, M. A.; Smith, T. A.; Bennett, A.; Yukich, J.; Eisele, T. P.; Griffin, J. T.; Fergus, C. A.; Lynch, M.; Lindgren, F.; Cohen, J. M.; Murray, C. L. J.; Smith, D. L.; Hay, S. I.; Cibulskis, R. E.; Gething, P. W. The Effect of Malaria Control on Plasmodium Falciparum in Africa between 2000 and 2015. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e2015\u003c/strong\u003e, \u003cem\u003e526\u003c/em\u003e (7572), 207\u0026ndash;211. https://doi.org/10.1038/nature15535.\u003c/li\u003e\n\u003cli\u003eMwaanga, G.; Ford, J.; Yukich, J.; Chanda, B.; Ashton, R. 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L.; Gergely, P.; Xue, R.-D.; Hausmann, A.; Beck, R.; Prozorov, A.; Diarra, R. A.; Kone, A. S.; Majambere, S.; Bradley, J.; Vontas, J.; Beier, J. C.; M\u0026uuml;ller, G. C. Large-Scale Field Trial of Attractive Toxic Sugar Baits (ATSB) for the Control of Malaria Vector Mosquitoes in Mali, West Africa. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2020\u003c/strong\u003e, \u003cem\u003e19\u003c/em\u003e (1), 72. https://doi.org/10.1186/s12936-020-3132-0.\u003c/li\u003e\n\u003cli\u003eBriet, O.; Koenker, H.; Norris, L.; Wiegand, R.; Vanden Eng, J.; Thackeray, A.; Williamson, J.; Gimnig, J. E.; Fortes, F.; Akogbeto, M.; Yadouleton, A. W.; Ombok, M.; Bayoh, M. N.; Mzilahowa, T.; Ab\u0026iacute;lio, A. P.; Mabunda, S.; Cuamba, N.; Diouf, E.; Konat\u0026eacute;, L.; Hamainza, B.; Katebe-Sakala, C.; Ponce de Le\u0026oacute;n, G.; Asamoa, K.; Wolkon, A.; Smith, S. C.; Swamidoss, I.; Green, M.; Gueye, S.; Mihigo, J.; Morgan, J.; Dotson, E.; Craig, A. S.; Tan, K. R.; Wirtz, R. A.; Smith, T. Attrition, Physical Integrity and Insecticidal Activity of Long-Lasting Insecticidal Nets in Sub-Saharan Africa and Modelling of Their Impact on Vectorial Capacity. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2020\u003c/strong\u003e, \u003cem\u003e19\u003c/em\u003e (1), 310. https://doi.org/10.1186/s12936-020-03383-6.\u003c/li\u003e\n\u003cli\u003eAb\u0026iacute;lio, A. P.; Obi, E.; Koenker, H.; Babalola, S.; Saifodine, A.; Zulliger, R.; Swamidoss, I.; Ponce de Leon, G.; Alfai, E.; Blaufuss, S.; Olapeju, B.; Harig, H.; Kilian, A. Monitoring the Durability of the Long-Lasting Insecticidal Nets MAGNet and Royal Sentry in Three Ecological Zones of Mozambique. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2020\u003c/strong\u003e, \u003cem\u003e19\u003c/em\u003e (1), 209. https://doi.org/10.1186/s12936-020-03282-w.\u003c/li\u003e\n\u003cli\u003eHiruy, H. N.; Irish, S. R.; Abdelmenan, S.; Wuletaw, Y.; Zewde, A.; Woyessa, A.; Haile, M.; Chibsa, S.; Lorenz, L.; Worku, A.; Yukich, J.; Berhane, Y.; Keating, J. Durability of Long-Lasting Insecticidal Nets (LLINs) in Ethiopia. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2023\u003c/strong\u003e, \u003cem\u003e22\u003c/em\u003e (1), 109. https://doi.org/10.1186/s12936-023-04540-3.\u003c/li\u003e\n\u003cli\u003eYewhalaw, D.; Simma, E. A.; Zemene, E.; Zeleke, K.; Degefa, T. Residual Efficacy of SumiShield\u003csup\u003eTM\u003c/sup\u003e 50WG for Indoor Residual Spraying in Ethiopia. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2022\u003c/strong\u003e, \u003cem\u003e21\u003c/em\u003e (1), 364. https://doi.org/10.1186/s12936-022-04395-0.\u003c/li\u003e\n\u003cli\u003eArnzen, A.; Wagman, J.; Chishya, C.; Orange, E.; Eisele, T. P.; Yukich, J.; Ashton, R. A.; Chanda, J.; Sakala, J.; Chanda, B.; Muyabe, R.; Kaniki, T.; Mwenya, M.; Mwaanga, G.; Eaton, W. T.; Mancuso, B.; Mungo, A.; Mburu, M. M.; Bubala, N.; Hagwamuna, A.; Simulundu, E.; Saili, K.; Miller, J. M.; Silumbe, K.; Hamainza, B.; Ngulube, W.; Moonga, H.; Chirwa, J.; Burkot, T. R.; Slutsker, L.; Littrell, M. Characteristics of the Western Province, Zambia, Trial Site for Evaluation of Attractive Targeted Sugar Baits for Malaria Vector Control. \u003cem\u003eMalar. J.\u003c/em\u003e \u003cstrong\u003e2024\u003c/strong\u003e, \u003cem\u003e23\u003c/em\u003e, 153. https://doi.org/10.1186/s12936-024-04985-0.\u003c/li\u003e\n\u003cli\u003eAttractive Targeted Sugar Bait Phase III Trial Group. Attractive Targeted Sugar Bait Phase III Trials in Kenya, Mali, and Zambia. \u003cem\u003eTrials\u003c/em\u003e \u003cstrong\u003e2022\u003c/strong\u003e, \u003cem\u003e23\u003c/em\u003e (1), 640. https://doi.org/10.1186/s13063-022-06555-8.\u003c/li\u003e\n\u003cli\u003eOrange, E.; Kyomuhangi, I.; Masuzyo, M.; Mwenya, M.; Mambo, P.; Saili, K.; Chishya, C.; Chanda, J.; Ashton, R.; Eisele, T.; Yukich, J.; Miller, J.; Silumbe, K.; Hamainza, B.; Wagman, J.; Arnzen, A.; Harris, A.; Entwistle, J.; Slutsker, L.; Littrell, M. \u003cem\u003eDeployment of Attractive Targeted Sugar Baits in Western Zambia: Installation, Monitoring, Removal, and Disposal Procedures during a Phase III Cluster Randomized Control Trial.\u003c/em\u003e; 2024. https://doi.org/10.21203/rs.3.rs-4224677/v1.\u003c/li\u003e\n\u003cli\u003eCensus-of-Population-and-Housing-Preliminary.Pdf. https://www.zamstats.gov.zm/wp-content/uploads/2023/05/2022-Census-of-Population-and-Housing-Preliminary.pdf (accessed 2024-01-13).\u003c/li\u003e\n\u003cli\u003eLynn, R. C.; Duquette, R. A. 6 - Antiparasitic Drugs. In \u003cem\u003eGeorgis\u0026rsquo; Parasitology for Veterinarians (Eleventh Edition)\u003c/em\u003e; Bowman, D. D., Ed.; W.B. Saunders: St. Louis (MO), 2021; pp 286\u0026ndash;348. https://doi.org/10.1016/B978-0-323-54396-5.00015-5.\u003c/li\u003e\n\u003cli\u003e\u003cem\u003eDinotefuran - an overview | ScienceDirect Topics\u003c/em\u003e. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/dinotefuran (accessed 2024-03-19).\u003c/li\u003e\n\u003cli\u003eBrookmeyer, R.; Crowley, J. A Confidence Interval for the Median Survival Time. \u003cem\u003eBiometrics\u003c/em\u003e \u003cstrong\u003e1982\u003c/strong\u003e, \u003cem\u003e38\u003c/em\u003e (1), 29\u0026ndash;41. https://doi.org/10.2307/2530286.\u003c/li\u003e\n\u003cli\u003e\u003cem\u003eR: The R Project for Statistical Computing\u003c/em\u003e. https://www.r-project.org/ (accessed 2024-06-16).\u003c/li\u003e\n\u003cli\u003eTherneau, T. M.; until 2009), T. L. (original S.-\u0026gt;R port and R. maintainer; Elizabeth, A.; Cynthia, C. Survival: Survival Analysis, 2023. https://cran.r-project.org/web/packages/survival/index.html (accessed 2024-02-06).\u003c/li\u003e\n\u003cli\u003eKassambara, A.; Kosinski, M.; Biecek, P.; Fabian, S. Survminer: Drawing Survival Curves Using \u0026ldquo;Ggplot2,\u0026rdquo; 2021. https://cran.r-project.org/web/packages/survminer/index.html (accessed 2024-02-06).\u003c/li\u003e\n\u003cli\u003eRondeau, V.; Gonzalez, J. R.; Mazroui, Y.; Mauguen, A.; Diakite, A.; Laurent, A.; Lopez, M.; Krol, A.; Sofeu, C. L.; Dumerc, J.; Rustand, D.; Chauvet, J.; Coent, Q. L.; Pierlot, R.; Hill, D.; Burkardt, J.; Genz, A.; Rego, A. J. Frailtypack: Shared, Joint (Generalized) Frailty Models; Surrogate Endpoints, 2023. https://cran.r-project.org/web/packages/frailtypack/index.html (accessed 2024-02-06).\u003c/li\u003e\n\u003cli\u003eTherneau, T. M. Coxme: Mixed Effects Cox Models, 2024. https://cran.r-project.org/web/packages/coxme/index.html (accessed 2024-05-12).\u003c/li\u003e\n\u003cli\u003eKleinbaum, D. G.; Klein, M. \u003cem\u003eSurvival Analysis: A Self-Learning Text\u003c/em\u003e, Third edition, corrected publication.; Statistics for biology and health; Springer: New York Dordrecht Heidelberg London, 2020.\u003c/li\u003e\n\u003cli\u003eDonga, T. K.; Bosma, L.; Gawa, N.; Meheretu, Y. Rodents in Agriculture and Public Health in Malawi: Farmers\u0026rsquo; Knowledge, Attitudes, and Practices. \u003cem\u003eFront. Agron.\u003c/em\u003e \u003cstrong\u003e2022\u003c/strong\u003e, \u003cem\u003e4\u003c/em\u003e. https://doi.org/10.3389/fagro.2022.936908.\u003c/li\u003e\n\u003cli\u003eKyomuhangi, I.; Yukich, J.; Saili, K.; Orange, E.; Masuzyo, M. H.; Mwenya, M.; Mambo, P.; Hamainza, B.; Wagman, J.; Miller, J.; Chanda, J.; Silumbe, K.; Littrell, M.; Eisele, T. P.; Ashton, R. A. Evaluating Trends in Damage to Attractive Targeted Sugar Baits Deployed during the Second Year of a Two-Year Phase III Trial in Western Zambia. June 6, 2024. https://doi.org/10.21203/rs.3.rs-4523449/v1.\u003c/li\u003e\n\u003cli\u003eAshton R.A.; Saili K.; Chishya C.; Banda H.; Arnzen A.; Orange E.; Chitoshi C.; Efficacy of Attractive Targeted Sugar Bait stations against malaria in Western Province Zambia: epidemiological findings from a two-arm cluster randomized Phase III trial. The Lancet Global Health (2024)\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Malaria, Attractive Targeted Sugar Bait, survival","lastPublishedDoi":"10.21203/rs.3.rs-4670314/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4670314/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eAttractive Targeted Sugar Baits (ATSBs) are a potential addition to the integrated vector management strategy against malaria. ATSB stations utilize the attract and kill method to control mosquitoes. Each ATSB station contains a sugar bait laced with an ingestion toxicant. This study measured the duration of physical integrity of the ATSB Sarabi v1.2 station used in western Zambia as part of a Phase III cluster randomized control trial.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eATSB stations were installed on external walls of 304 sleeping structures, in 206 households (10\u0026ndash;11 per cluster within 20 clusters). Monthly visits were made to assess for the presence and condition the ATSB stations from November 2022-June 2023. A rolling cohort approach was used, whereby newly installed, and replacement ATSB stations were included in the study. Information on structure construction and location of ATSB stations on walls was collected. Median ATSB survival and associated factors were analyzed with Kaplan-Meier curves and Cox-Proportional hazard models, respectively.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eIncluding replacements, a total of 1107 ATSB stations were installed across 304 sleeping structures and 5696 ATSB-visits were made. Common types of damage observed were holes/tears, mold, and leakage of bait. While the median survival time for the ATSB stations was five months (149 days) for all stations in the study, the median survival time was longer than the transmission season for stations installed in locations well protected by the roof (\u0026gt;\u0026thinsp;218 days). ATSB station survival was longer when installed on structures with thatched roofs compared to iron sheet roofs (Hazard Ratio 0.37, 95% confidence interval 0.26\u0026ndash;0.47, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and where there was \u0026lsquo;excellent protection\u0026rsquo; (HR\u0026thinsp;=\u0026thinsp;0.36, 95% CI 0.25\u0026ndash;0.49, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), compared to \u0026lsquo;no protection\u0026rsquo;.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eStudy results suggest that the majority of Sarabi v1.2 ATSB stations deployed in this setting will remain intact for a 7-month seasonal deployment period if stations are installed in locations protected from rain and wind such as underneath a thatched roof. Further research is needed to understand factors that influence the physical integrity of ATSB stations in addition to those observed in this study.\u003c/p\u003e","manuscriptTitle":"Time to loss of physical integrity of Attractive Targeted Sugar Bait (ATSB) stations in Western province, Zambia: a survival analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-31 05:51:57","doi":"10.21203/rs.3.rs-4670314/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"21f389ce-b42d-48fe-9022-b7fda1c62a62","owner":[],"postedDate":"July 31st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-26T12:23:25+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-31 05:51:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4670314","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4670314","identity":"rs-4670314","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}