Influences on limited antimicrobial use in small-scale freshwater aquaculture farms in central Thailand

1 1 Influences on limited antimicrobial use in small-scale 2 freshwater aquaculture farms in central Thailand 3 4 Nour Alhusein1*, Boonrat Chantong2, Sarin Suwanpakdee2, Anuwat Wiratsudakul2, Virginia C. 5 Gould3,#a, Kantima Wichuwaranan 4, Kornrawan Poonsawad 4, Varapon Montrivade 4, Nutcha 6 Charoenboon1, Luechai Sringernyuang 4, Matthew B. Avison 5, Helen Lambert 1, Walasinee 7 Sakcamduang2, Henry Buller6†¶, Kristen K. Reyherg¶* 8 9 1 Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK 10 2 Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand 11 3 Bristol Veterinary School, University of Bristol, Bristol, UK 12 4 Faculty of Social Science and Humanities, Mahidol University, Salaya, Nakhon Pathom, 13 Thailand 14 5 School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom 15 6 College of Life and Environmental Sciences, University of Exeter, Exeter, UK 16 #aCurrent Address: School of Psychological Science, University of Bristol, Bristol, United 17 Kingdom 18 *Corresponding authors: 19 [email protected] (NA) 20 [email protected] (KR) 21 22 ¶HB and KR are Joint Senior Authors 23 †Deceased . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. 2 24 Abstract 25 Recent years have shown substantial growth both in the scale and the spread of freshwater 26 aquaculture in Thailand, raising concerns about potential widespread antimicrobial use. This 27 mixed-methods study used surveys and qualitative interviews to examine conditions of 28 freshwater aquaculture farming in central Thailand in relation to animal health, disease 29 management and patterns of antimicrobial use. Freshwater aquaculture in this area of 30 Thailand was largely a domestic venture operated as a source of additional household income 31 to increase financial security. Aquaculture was often integrated with other types of farming; 32 initial outlay was reduced by repurposing unused crops, food, or animal manure (e.g. chicken 33 droppings and pig dung) to fertilise aquaculture ponds. Among farmers representing twenty 34 farms who were surveyed during 2019, only six farmers said they used antimicrobials. These 35 included oxytetracycline, enrofloxacin, norfloxacin, ciprofloxacin and sulphonamides. 36 Farmers doubted the benefits of using antimicrobials to treat aquatic animals; some believed 37 antimicrobials stunted growth. The high cost of medicines and prohibitive regulations also 38 discouraged antimicrobial use. Farmers linked disease occurrence to changes in the weather, 39 the emergence of new diseases and variable water quality. They relied on farm management 40 practices to maintain the health of their aquatic animals, using lime and salt to maintain and 41 improve water quality and pH and to disinfect aquaculture pools. Farmers also reported 42 obtaining juvenile fish and shrimp selectively from farms known to produce healthy stock. 43 Specialised veterinary services for aquatic farming were rare, so farmers relied on their own 44 experimentation with medicines, peer advice and recommendations of shopkeepers who sold 45 both aquatic feed and medicines. This study unexpectedly reveals limited use of . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 3 46 antimicrobials linked to socio-economic and ecological features of small-scale family 47 aquaculture farms. 48 49 Introduction 50 Fast-developing aquaculture sectors in several Southeast Asian countries have been seen as 51 contributors to the rapidly expanding and diversifying antimicrobial resistance (AMR) 52 documented in animal production systems over the last two decades [1-3]. Analysis of point 53 prevalence surveys reporting AMR from aquatic food animals in Asia has found concerning 54 levels of resistance to medically important antimicrobials in foodborne pathogens [4]. 55 Increased antimicrobial use (AMU) is associated with the emergence of AMR in bacteria, with 56 significant implications for both animal and human health [5]. Schar et al. estimated that by 57 2030, AMU in aquaculture will constitute 5.7% of global AMU and will carry the highest use 58 intensity per kilogram of biomass [6]. 59 60 Thailand has been part of the Asian aquaculture surge, being ranked 13th among aquaculture 61 country producers with a production of 889,891 tonnes of live weight in 2017 [2]. Its 62 industries predominantly centre on coastal production of shrimp, molluscs and prawn in salt- 63 water ponds. More recent years, however, have seen the significant growth of inland, fresh- 64 water aquaculture in Thailand [7]. Here the early emphasis has been rather more on the 65 production of fish species, notably catfish and tilapia, though shrimp production has grown 66 rapidly and displayed a similar dynamism to that of the coastal regions [8]. In 2015, freshwater 67 aquaculture in Thailand accounted for 45% of total aquaculture production value, with the 68 remainder from marine/coastal aquaculture [7]. . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 4 69 The growth of inland Thai aquaculture (both shrimp and fish) has given rise to many debates, 70 despite its very clear profitability for those involved [9,10]. There are concerns about the 71 sustainability of the older model of domestic rice production in many areas of central Thailand 72 - the widescale and highly profitable conversion of paddy fields to aquaculture ponds has 73 accompanied this transition, changing the nature and regulation of the rural communities 74 that rice traditionally sustained [8,11,12]. A second concern has been the use, over-use and 75 management of fresh-water resources, both river and canals, as critical and replenishable 76 growing media for aquatic species at a time when other uses of water are being employed, 77 particularly as a means of moving effluent and wastewater out of sites of production. Little 78 empirical evidence currently exists as to whether inland aquaculture alone makes a major 79 contribution to river and canal pollution or whether, alternatively, aquaculture can place itself 80 principally as the victim of pollution from urban and industrial sources [13]. 81 82 A third concern about Thai aquaculture, alongside most agriculture systems globally, has been 83 expressed: that emergence of AMR in environmental or animal-borne pathogens is driven by 84 AMU on aquaculture farms, resulting in the increased potential for AMR infections in humans 85 [14-17]. Indeed, the rapid growth and spread of the Thai marine aquaculture industry in the 86 early 2000s was characterised by high profit margins sustained by a wide range of chemical 87 inputs (including the use of antimicrobials) to prevent and treat diseases as well as improve 88 water quality [18]. These inputs took place in an environment where many production-related 89 diseases were present and unchecked, where increasingly concentrated fish and shrimp 90 species were vulnerable to disease outbreaks and where, initially, a relatively unregulated 91 legal framework governed AMU in animal farming [19-21]. The result was that much of the . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 5 92 Thai aquaculture sector developed with relatively high levels of prophylactic AMU being the 93 norm, particularly in the coastal zone [22]. 94 95 Recent years have seen establishment of several significant regulatory and policy initiatives 96 in Thailand to survey, monitor and reduce AMU in aquaculture [23,24]. Under these 97 regulations, only the antibacterials oxytetracycline, tetracycline hydrochloride, 98 sulfadimethoxine, trimethoprim, sulfadimethoxine/ormetoprim, amoxicillin and enrofloxacin 99 are authorised in aquaculture [23]. Several market initiatives have followed suit with major 100 retailers and food processing groups seeking to limit AMU within their Thai supply chains (e.g. 101 the Raised Without Antibiotics initiative) [25]. The first five-year National Strategic Plan on 102 AMR in Thailand was published in 2016, covering the period 2017 to 2021 [26]. Since then, 103 legislation has tightened the availability and accessibility of antimicrobials for aquaculture and 104 reinforced the role of the veterinarian in antimicrobial prescribing. Moreover, AMU for 105 growth promotion has been prohibited, and certain antimicrobials considered critically 106 important for human health have been made unavailable for use in aquaculture. These 107 changes were in parallel with those in many other major international food-trading nations. 108 109 Investigating current aquaculture practice 110 Fifty kilometres outside Bangkok, a wide river flows south through the agricultural district of 111 ‘Plakat’ [a pseudonymised district name has been used to maintain anonymity], part of a 112 larger administrative province. This is a flat fertile landscape with an elaborate network of 113 irrigation systems and canals, bearing witness to agricultural and industrial activities following 114 a period of land reformation. Rice fields and other field crops, vegetable farms, fish ponds, . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 6 115 shrimp ponds, chicken, duck and pig farms are numerous in the district. There are also 116 industrial factories and solar energy power stations. In agricultural terms, over the last two 117 decades there has been a notable shift (as there has across much of central Thailand) from 118 the more longstanding production of rice to more profitable, low salinity freshwater fish 119 (notably tilapia) and shrimp production. Local fish markets serving Bangkok and nearby 120 provinces provide critical commercial infrastructure, along with a range of aquaculture sector 121 industries which include food-processing factories as well as feed and animal suppliers. With 122 such animal production - and its associated commercial and market exigencies - come new 123 and different pressures notably around health (both animal and public health), disease 124 management and resource control, which interlink with the growing national agenda of 125 antimicrobial surveillance and reduction mentioned above. 126 127 In an effort to identify the principal drivers of AMU in aquaculture and understand how inland, 128 small-scale aquaculture farmers respond to shifts in animal health practice and regulation, 129 our team spent a year in Plakat district, conducting research with freshwater prawn and fish 130 farmers as part of a wider project to build a holistic picture of AMR drivers in Thailand from 131 the One Health (human-animal-environment) perspective [27]. We investigated aquaculture 132 farm management practices and attitudes towards AMU as well as the information and 133 advisory networks they had for information about antimicrobials and aquatic animal health. 134 135 136 Materials and Methods . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 7 137 A mixed methods approach was employed comprising a cross-sectional survey along with 138 semi-structured interviews. 139 140 Materials and participant recruitment 141 Primary research was undertaken through a questionnaire-based farmer survey 142 supplemented by additional information obtained by a parallel series of semi-structured local 143 community (household) interviews, undertaken as part of this research programme but 144 oriented more specifically to human health and AMU (Fig 1). 145 146 Fig 1. A diagram showing the methods and the data sources involved in this study. 147 148 Farmer survey 149 The purpose of the questionnaire survey was to explore the aquaculture farms and animal 150 health management practices as well as AMU. A questionnaire was developed by the Thai and 151 UK research teams that combined closed, open-ended and multiple choice questions covering 152 three main areas: first, farm structure and farmer demographics; second, animal production 153 and health; and third, medicine use including knowledge, advisory systems and networks 154 used by farmers, with a particular emphasis on antimicrobials (Farmer survey in S1 Appendix). 155 Data collection was conducted between October 1, 2019, and ended on December 20, 2019. 156 A purposive sampling was followed based on geographical area and farm type. The farms 157 were geographically centred around the principal settlement of ‘Plakat’ but stretched across 158 the river basin and extensive local canal system. A total of 20 aquaculture farms were 159 recruited: nine fish farms and 11 shrimp farms. The survey was conducted face-to-face (social . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 8 160 distancing in place due to COVID-19 pandemic) with the farm owner by different members of 161 the research team (BC, SS and/or AW). On a few occasions, co-workers were present and 162 contributed to the discussion. Informed consent was obtained from all participants. All 163 participants needed to sign a consent form before participating in the study. Only adults 164 participated in the study. Open-ended questions were all in Thai, were audio recorded and 165 subsequently translated to English and analysed. Responses to the closed and multiple-choice 166 questions from the questionnaire were analysed and will be reported in future manuscripts. 167 (BC, SS, AW) are researchers with a speciality and training in veterinary sciences. 168 169 Additional interviews with households 170 Additional qualitative interviews were undertaken with local residents, including aquaculture 171 farmers, in the district as part of the wider project’s aim to understand local attitudes towards 172 human health, AMU and AMR. These also provided additional information on aquafarming 173 and animal health practices. Nineteen households were interviewed by researchers (KW, KP 174 and NC) and later analysed for the aquafarming theme. Data collection took place between 175 February 2019 and August 2021. The sample was purposively selected based on geographical 176 area and socio-economic diversity. Initial contact was made by the village health volunteers 177 (community health workers) who introduced the study on behalf of the research team [28]. 178 Households who were happy to participate were introduced to the researchers. All visits were 179 made on an invitation/permission basis from the key informant of the household. Social 180 distancing rules were applied due to COVID-19 pandemic. On average, at least 5 visits were 181 made to each household. Monthly visits were made to some households with which the 182 research team had developed deeper relationships. Time per visit varied from the early (30- 183 60 min) to the later (1-3 hours) period of fieldwork. An informed consent was obtained from . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 9 184 all the households. Only adults participated in the study. Other adult family members 185 contributed to interviews if they were present. Interviewees were in effect self-selected from 186 among family members according to availability, but efforts were made to ensure a 187 representative spread of occupations and ages across the overall sample. The three main 188 themes for investigation included living conditions (livelihoods, food and water sources), 189 health and treatment-seeking (including medicine use) (Interview topic guide in S2 Appendix). 190 Researchers used both audio recorders and field notes to record these visits. Out of 19 191 households, almost half (nine) were identified as running small aquafarming businesses. (KW, 192 KP, NC) are trained qualitative researchers with background in anthropology. 193 194 Data management and analysis 195 Interview transcripts and responses to open-ended questions were recorded, transcribed and 196 translated into English. These transcripts were then coded using open coding and analysed 197 thematically [29] using NVivo qualitative data analysis software (Version 12, QSR 198 International, Melbourne, Australia). A thematic analysis approach enables exploring the data 199 in depth and identifying patterns of meaning across the data. The first step involved NA 200 reviewing the transcripts through the stages of familiarization and assigning initial inductive 201 codes to a sub-sample of transcripts. An initial coding framework was developed and 202 discussed with the rest of the research team. The remaining transcripts were then indexed by 203 NA using the coding framework and refinements were made as necessary. NA then re-read, 204 reviewed and clustered the identified codes to form inductive themes and sub-themes and 205 assigned names to the themes. The process was iterative and since the data were translated 206 from Thai, cross-checking of accuracy of interpretation went on throughout the analysis . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 10 207 through continuous discussion with the Thai researchers and the rest of the research team. 208 Illustrative quotes from the farmer survey are presented with descriptors including the farm 209 type (fish or shrimp) and the farm ID number (e.g. fish farmer F3 or shrimp farmer S4). 210 Illustrative quotes from household data are presented with descriptors including the farm 211 type (fish or shrimp) and household ID number (e.g. fish farmer HH38). 212 213 Ethics 214 Formal ethical approval was received from Mahidol University Social Science Institutional 215 Review Board [(Certificate of Approval No. 2019.026.0702), (MUSSIRB No. 2019/024 (B2)], 216 and Faculty of Veterinary Science, Mahidol University – Institute Animal Care and Use 217 Committee (FVS-MU-IACUC), (license no: UI-01292-2558) and registered with University of 218 Bristol, UK. 219 The study used mixed methods including a survey of farmers and semi-structured interviews 220 with adult members of households in the local community. For the farmer survey, written 221 consent was obtained from all participants. For semi-structured interviews, written consent 222 was requested before the commencing of data collection from all households. Some 223 households initially preferred to give a verbal consent. In this case, the verbal consent was 224 obtained and witnessed by another member of the research team, other household members 225 and village health volunteers (Community health workers) who helped in the recruitment. 226 Subsequent confirmation of consent was ensured on an ongoing basis (e.g. repeated requests 227 for permission for household visits), in line with the Association of Social Anthropologists of 228 the UK (ASA) Ethical Guidelines for good research practice (ASA 2021). Later, written consent 229 was obtained from all households for other data collection activities (e.g. household survey, . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 11 230 stool samples, reported elsewhere). For each activity, the research team explained to 231 participants the study objectives and procedures, the voluntary nature of participation, 232 principles of confidentiality and anonymisation of data. The consenting procedure (written or 233 verbal) was approved by Mahidol University Social Science Institutional Review Board. 234 235 236 Results 237 Farm characteristics 238 Most farmers had members of their families living on the farm and working with animals. All 239 farms were owned by the farmer; none were contracted from a company. Fifteen farmers 240 had established the farms by themselves, three were inherited and two rented. Fish farmers 241 mainly raised tilapia ( Oreochromis niloticus). Other species included giant gourami 242 (Osphronemus goramy), Jullien’s golden carp (Probarbus jullieni) and other carp species 243 (Cyprinidae). Shrimp farmers raised Pacific white shrimp ( Litopenaeus vannamei) and giant 244 freshwater prawn (Macrobrachium rosenbergii) (Farm characteristics in S3 Table). 245 246 Household characteristics 247 It was very common for household members to have multiple occupations (Household 248 characteristics in S4 Table). Of the nine households, seven had private ponds used to raise 249 fish or shrimp. Others had a cage (or floating baskets) used for raising fish in shared ponds or 250 in the river (Fig 2). 251 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 12 252 Fig 2. Left: Fishpond. Middle: Drained fishpond with protective nets. Right: Shared fishery 253 in a pond or river. 254 255 256 257 258 259 Three main themes and nine subthemes were generated from the analysis (Fig 3). 260 261 Fig 3. Thematic map of the themes and subthemes identified in the data. 262 263 Health management practices 264 Pond preparation and disinfection 265 Farmers grew fish and shrimp in ponds dug out of the ground. To prepare the ponds for new 266 stock, farmers would leave emptied ponds to dry out, clean the floor of the ponds and then 267 add new water. Drying periods varied; one farmer spoke of allowing the floor to dry for 40- 268 60 days while others mentioned a few days to two weeks. Once the soil was dry, most farmers 269 scattered lime (calcium hydroxide or calcium carbonate) on the pond floor to disinfect the 270 ground. Farmers also reported using other chemicals including herbicides or quicklime 271 (calcium oxide) with two interviewees speaking of disinfecting their ponds with ‘germ-killing’ 272 medicines (a local term generally used to refer to antibiotics or disinfectants). Treated ponds 273 were left between one to 10 days, before water was added. 274 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 13 275 “We put in lime first to kill the germs... 276 Researcher: For how many days, approximately? 277 “Three days.” Shrimp farmer S4 278 279 “To prepare the ponds, we fill them with water. Fill it up to the height that we think 280 the fish can go in. Then disinfect the ponds using ‘germ-killing’ medicines.” 281 Researcher: Do you also use lime before [putting the water in] at all? 282 “No, no need.” Fish farmer F8 283 284 Almost all farms obtained water for the ponds from the canal system connected to the river. 285 Water levels were monitored and usually adjusted to a level of around one metre depth. 286 Additives were often added to the ponds. These included salts, micro-organisms, ‘germ- 287 killing’ medicines and fertilizers. The pond water then was usually left for around a week 288 before the fish or shrimp were introduced. One farmer mentioned waiting for the water to 289 ‘turn green’ before adding juvenile shrimp. Some farmers also checked the pH of the water. 290 291 “We scatter microbes [micro-organisms] and germ-killing medicines into the 292 ponds, then we fill in water. After three days or a week, the shrimplets [baby 293 shrimp] can go in.” Shrimp farmer S5 294 295 “Sometimes we also add salt into some ponds to treat the soil and the water, to 296 not let the water be too acidic or basic.” Fish farmer F5 297 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 14 298 “[…] add water. followed by tablet fertilizer to prime the floor. That’s it.” Shrimp 299 farmer S10 300 301 “Interviewee: When the water goes in, we add microbes [micro-organisms] to 302 treat it first. 303 Researcher: That’s before you put the shrimps in. 304 Interviewee: Yes. We use lime and microbes. 305 Researcher: Do you buy the microbes or do you make that yourself? 306 Interviewee: We buy. Sometimes we use [product name]. We use [product name] 307 to ferment first, then we use [another product] to adjust the water condition… 308 Researcher: From then, do you leave it for many more days? 309 Interviewee: We leave it for another week before we put the shrimp in.” Shrimp 310 farmer S4 311 312 Stock management 313 Buying the aquatic animals from trusted sources was vital to farmers as such a practice meant 314 fewer diseases later. New fish were usually kept together in a single, protective ‘nursery pond’ 315 for an initial two and a half to three months. When the fish had grown in size and weight, they 316 were divided between different ponds. Just over half the farmers reported co-housing 317 different species. It was common for shrimp farmers to raise giant freshwater prawns and 318 white shrimp together in the same pond. One farmer raised fish and shrimp together. Other 319 animals like poultry (in small-scale production) roamed freely around the ponds or walked on 320 the nets covering the ponds. 321 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 15 322 “But if you want to raise the fish together with the shrimp, you have to put the 323 shrimp in first. We take that water to test in a lab; there’s a lab in [town]. If the 324 water passes [the standards], then we can release the shrimps. Fifteen days after 325 the shrimps go in, the fish can go in – tilapias and seven-striped carp and Chinese 326 fish. Then we raise them.” Fish farmer F7 327 Feeding and nutrition 328 Farmers explained that the aquaculture farming rearing cycle was generally operated over a 329 one-year period. This period could be reduced to six to eight months depending on the 330 farmer’s feeding style, whether they used organic feed or commercial supplements. 331 Commercial supplements accelerated the growth of fish and shrimp, but not everyone could 332 afford them. Some farmers used animal manure, sourced from their other livestock such as 333 ducks, chicken, or pigs, to feed fish or shrimp in the ponds. This practice was seen as a way to 334 reduce cost as well as being wise use of resources. One farmer mentioned having direct 335 pipelines from their pig sheds through which dung was pumped into the ponds. Another 336 farmer sold the extra dung they had to other farmers. Animal manure usage, however, was 337 disapproved of by some other farmers due to its unpleasant smell. Farmers also reported 338 using other types of organic or locally available sources of fertilizers such as vegetables from 339 their garden, lotus, hay or rice bran either alone or mixed with powdered fishmeal usually 340 given to small fish. One farmer mentioned using the wastewater from a fertiliser factory and 341 another fed fermented pineapple peel to the shrimp. One participant described using unused 342 noodles from a nearby factory. Vitamins were also used, though one farmer described them 343 as a waste of money. 344 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 16 345 “I took pig dung to feed the fish. When I wash the pig dung from this coop, the 346 water flows down two pipes; it flows into the fishpond.” Fish farmer HH38 347 348 “Feed this fish only grain and rice bran. Mix rice bran with pellet food. Chicken 349 manure, […] even the low cost, but the son doesn't like it, he doesn't want it. 350 Chicken manure is smelly too. Big pond over there [ different farm]. The owner of 351 the big pond raised it with chicken manure. Feed both pellet food and chicken 352 manure. That fishpond was delivered by a truck of chicken manure. Feeding the 353 fish like that makes the fish grow fast.” Fish farmer HH03 354 355 “The noodles were brought to the fish to eat, but the noodles had to be marinated. 356 Other farms do this. It has to add molasses water to mix in the tank as well. They 357 buy from sugar factories.” Fish farmer HH03 358 359 “I feed the fish with leftover food, vegetables that I bought to cook and then I throw the 360 rest to the fish in the pond.” Fish farmer HH25 361 362 Disease control and medicine use 363 Disease drivers 364 Many farmers reported that diseases amongst their stock had increased over the last decade. 365 While some farmers offered no explanation for this, others felt different factors were 366 responsible including weather changes, the emergence of new diseases and decreasing water 367 quality due to pollution. . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 17 368 369 “In the past they never got sick; if we found a few sick or dead ones we will just 370 remove them.” Shrimp farmer S11 371 372 “Lately, we don’t know what’s wrong with the fish, but they keep dying.” Fish 373 farmer F6 374 375 “If the water is good and the weather is good, we don’t need to use any medicine.” 376 Fish farmer F4 377 378 There was no consensus whether it was the heat or the cold that caused disease in the fish or 379 shrimp, but it seemed that the extreme weather conditions led to disease spreading. 380 381 “The disease outbreak is usually at the end of winter/beginning [of] summer. 382 Maybe, because of the heat, not sure, March-April. I give them medication and 383 add a lot of water. I don’t know, maybe because it is getting warm around that 384 time of the year.” Fish farmer F6 385 386 “Researcher: You mentioned that the animals died a lot during the past year ... 387 how did it happen? What were the symptoms? 388 Interviewee (1st male): It is the heat. 389 Interviewee (2nd male): The weather is too hot, and they [the fish] got sick.” Fish 390 farmer and co-worker F7 391 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 18 392 “If the weather keeps getting colder, we will probably have to buy them 393 medication.” Fish farmer F9 394 395 “They are currently healthy, because right now the temperature is dropping. Once 396 it got cooler, they are able to survive. But they would also start showing symptoms 397 if it is getting too cold.” Shrimp farmer S5 398 399 Water condition was considered vital in raising healthy aquatic animals and was monitored 400 continuously, largely through attention to its colour, appearance and pH. Poor-looking water 401 was often treated using additives such as salt, micro-organisms and ‘germ-killing’ medicines. 402 Two farmers spoke of the impact of rain on the water conditions. Others spoke of the 403 importance of oxygenating the water, sometimes artificially. Critically, these water quality 404 and environmental factors played a part in determining subsequent antimicrobial and other 405 medicine use. 406 407 “After one month, we add more water and salt. We have to take note of the water 408 colour. If the colour starts to look bad – if it’s not green or clear – then we have to 409 add salt or minerals.” Shrimp farmer S9 410 411 “It depends on the weather and the water. For example, when we left them out during 412 the rain, then they would start dying. They are unable to survive under that condition, 413 because of the dropping pH, and alkaline, the shrimps are unable to adapt.” Shrimp 414 farmer S5 415 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 19 416 “I think the rain is toxic. I think. My opinion, not sure how true it is.” Fish farmer F8 417 418 “It depends on the water. If the water quality is good, it would be acceptable for us not 419 to add any medicine.” Shrimp farmer S3 420 421 Half the farmers reported having significant animal disease outbreaks or mass dying events 422 recently, with six reporting estimated mortality rates of over 20% - in one case, rising to 80% 423 of stock. One farmer described disease symptoms in fish as “red belly, disease in the eye, 424 swollen navel” (Fish farmer F9). Another looked for specific symptoms such as bruises as signs 425 of disease. For most, shrimp or fish feeding rates and mortality levels served as the basic 426 indicators of animal population health. One farmer mentioned using a lifting net to examine 427 the fish closely or shining a light at them at night. 428 429 “The amount of death is uncertain because we can see only when the dead fish 430 are floating.” Shrimp farmer S2 431 432 “When they got sick, when they started to die. Once they died, they will float, and 433 we just need to determine what kills them. Like, if they have bruises, we would 434 have a look and decide on bacterial or viral, and then we would treat them 435 accordingly.” Fish Farmer F6 436 437 “Researcher: From your experience, you lift Yo (a tool for trapping fishes) to see 438 how they are? . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 20 439 “Yes. We also can see when the fishes come up to the side of the bank. We shine 440 the light to see them during the night time… we check whether they (shrimp) have 441 tight texture or black gum…have foods in their intestines.” Shrimp farmer S7 442 443 "It doesn't work": AMU on aquaculture farms 444 Farmers were generally divided as to whether AMU on aquaculture farms had increased or 445 decreased in the last decade. Those that mentioned AMU decreasing argued that medicine 446 cost was high and that aquaculture farming simply did not generate enough revenue to cover 447 this cost. Some doubted the benefits of using antimicrobials in treating aquatic stock, 448 believing antimicrobials actively stunted growth. For a few respondents, government 449 regulations along with food chain and market imperatives mitigated against the use of 450 antimicrobials. 451 452 “[AMU] decreased, to decrease the running cost of the farm... Because, antibiotics 453 are expensive and sometimes ineffective.” Shrimp farmer S9 454 455 “Mostly, they [aquaculture farmers in general] don’t use [antimicrobials] 456 anymore… It doesn’t work.” Fish farmer F4 457 458 “However, even medicines did not really help… when we give them medications it 459 looks like they won’t grow, it looks like the medicines stunted their growth.” Fish 460 farmer F7 461 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 21 462 “I heard that people say it’s not good if we use too much. If we sell the shrimps and 463 the merchant/buyer checks and detects the drug use, we won’t be able to sell our 464 shrimps anymore. That is the reason why I try to limit the usage of medicine with 465 my shrimps.” Shrimp farmer S3 466 467 “For medicine, we may not use it at all because the Department of Fisheries already 468 told that it will be problem if medicine is detected. We used to face that problem.” 469 Shrimp farmer S6 470 471 Such farmers preferred to use other methods to control disease. These included selecting 472 reputed aquatic animal providers from which to purchase stock, using herbal medicines and 473 adding vitamins to enhance growth. As stated above, water quality was seen as an important 474 factor in keeping the stock healthy, often with additions of salts and lime. In the case of major 475 disease outbreaks, farmers regularly removed any floating dead fish and shrimp and would 476 deploy emergency harvesting if needed. Emergency harvests were either sold for sauce 477 production or became landfill. Infected ponds were then disinfected, and water was pumped 478 out to prepare for a new batch. 479 480 “Mostly, I don’t use [antimicrobials]. Because we focus on the species (of aquatic 481 animals) that we got from different farms…they are not similar.” Shrimp farmer S6 482 483 “Now people mostly use organic methods… we just won’t use it [antimicrobials]. 484 We will concentrate on natural/organic ways.” Shrimp farmer S4 485 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 22 486 “Yes. I use only herbs I bought from the food shop. I remember that it made from 487 turmeric, which human also can eat … If vitamins, we use sometimes … When I find 488 that some ponds grow slowly, I make a decision by myself to use vitamin 489 supplements.” Shrimp farmer S6 490 491 “To avoid using antimicrobials, we prepare the pool and water by adding 492 microorganisms; oxygenate the water, to help strengthen the animals, so that they 493 won’t be bothered by any diseases.” Fish farmer F3 494 495 “Researcher: What did you do with the dead ones, did you bury them? Or sell them? 496 Interviewee: We sold them. We sold them as “Phla-ra” [salt-fermented fish (not 497 fish sauce) commonly used in many Thai dishes]. Thirteen tons of Phla-ra.” Fish 498 farmer F8 499 500 “During [disease outbreak] we catch them; if we see they die, we must hurry to 501 catch them. If we let it be, they will all die.” Shrimp farmer S8 502 503 Other farms surveyed reported that their use of antimicrobials had increased in recent years 504 in response to growing disease prevalence. Prophylactic use of antimicrobials was often 505 described, particularly when an outbreak on a neighbouring farm was discussed. As a 506 treatment, antimicrobials were largely considered to be a last resort and were far from being 507 seen as being effective in treating sick animals or populations. Most farmers were unable to 508 name specific antimicrobial medicines, recognising them rather by their appearance or 509 characteristics. . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 23 510 511 “I think the use [of antimicrobials] is increased. Nowadays, diseases of aquatic 512 animals are more and more every day. We need to use antibiotics for curing their 513 diseases.” Fish farmer F2 514 515 “However, I occasionally give them medicine for disease prevention if there is a 516 disease outbreak and others say I should give them as a prevention measure.” 517 Shrimp farmer S4 518 519 “[…giving them antimicrobials] To stimulate them. […] To prevent them from 520 getting sick… we don’t give them that often, sometimes we would refrain from 521 giving them the medication. If they look responsive, we won’t give them any.” 522 Shrimp farmer S3 523 524 “We don’t know what else we could do. We already try changing the water, and 525 aerating; we already did everything, but it didn’t work. So, we have to turn to using 526 medications.” Fish farmer F6 527 528 “[…] Like when they ate [the medicine] for seven days in a row, they stop [dying]. 529 However, if we stop giving them the meds, they will start dying again. They are not 530 completely cured. We don’t know how to solve this.” Fish farmer F8 531 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 24 532 “If we see giant freshwater prawns die, then we use yellow medicine. That’s it. 533 Nothing much here because we don’t want to invest too much. The price of the 534 shrimp [to sell] is low.” Shrimp farmer S3 535 536 Out of the 20 farms, only six farms reported using antimicrobials including oxytetracycline, 537 fluoroquinolones (enrofloxacin, norfloxacin and ciprofloxacin) and sulphonamides. Farmers 538 reported purchasing antimicrobials from feed companies or stores and mixing these with feed 539 on the farms. Farmers did not mention obtaining antimicrobials from veterinarians. Other 540 additives were also used including multivitamins, amino acids and probiotics. The dosage and 541 frequency were mostly determined by the farmer and varied significantly between farms, 542 suggesting the absence or lack of knowledge of common guidelines within this small-scale 543 commercial aquaculture sector. Treatment plans were pond- and population-based. When 544 some fish or shrimp showed signs of sickness, the entire pond would be treated with the 545 medicines mixed with the feed or water and spread manually into the pond. 546 547 “There is a powder medicine that we can mix in water and put in the pond.” 548 Researcher: That would be for the entire pond? 549 “Yes. Some people would mix it in the food. It’s different for each farm.” Shrimp 550 farmer S11 551 552 “We cure them all in a pond. If this pond was cured, I can leave them and take care 553 of the next pond.” Shrimp farmer S8 554 555 Farmers’ perspectives on AMU and AMR . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 25 556 Farmers were asked what they thought about the long-term impact of AMU on humans, 557 animals or the environment. Misinformation or lack of awareness was evident as some 558 farmers felt there was no negative impact from AMU. 559 560 “I haven’t seen any effects from the use of antimicrobial so far, neither has anyone 561 come to clarify/educate us about it.” Fish farmer F3 562 563 “It’s not harmful to humans… My opinion would be that our use of medicines isn’t 564 harmful and doesn’t affect the consumer; even the biologist that gave us the 565 medication said that there is no effect.” 566 Researcher: What about these medicines – germ killer? Do you think they have any 567 effects on the consumer? 568 “No.” Shrimp farmer S4 569 570 “Researcher: Do you know about the effects of using antibacterial drugs on human, 571 animals and environment? Is there any effect when we use them for a long time? 572 “Interviewee: No, I don’t know. I don’t really study about this, so I don’t know 573 much.” Shrimp farmer S7 574 575 Other farmers believed that AMU could affect consumers due to chemicals accumulating in 576 the body and subsequently causing illnesses. However, these farmers explained that using 577 antimicrobials was necessary, especially in large farms with many animals. 578 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 26 579 “I know that if we use a significant amount of medicines with the animal, it will 580 affect the consumer as well. The antibiotics we used would accumulate in the 581 human body, causing it to resist drug action afterwards. So, yes. I know that it 582 would cause drug resistance in the human body when we use it to treat illness later 583 on.” Fish farmer F6 584 585 “If we use too much medicine for a long time, it would definitely be harmful to humans 586 because it would accumulate in our body. But it is necessary to use medication because 587 we need to medicate the animal when they get sick, especially for those big farms that 588 have a lot of animals.” Shrimp farmer S11 589 590 Advice and support networks for disease management and AMU provision 591 The farmers interviewed stated that they had autonomy over the health management and 592 treatment decisions taken on their farms. Farmers tended to learn what treatment to use 593 through their own experimentation with different products and their impact upon illness 594 symptoms and animal health. 595 596 “I decide from the symptom whether to use Oxy [oxytetracycline], Sulfa 597 [sulfonamides], Enro [enrofloxacin], or others. There are 2 to 3 primary medicines 598 that I use nowadays.” Fish farmer F8 599 600 “If I use any product, and it’s good, then I continue using that [laugh]… I have no 601 one to do research for me. So, I must do it myself. If I give the fishes any medicines 602 and see that during the three days they get better, then I continue using that one. . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 27 603 But if they don’t get better within three days, then I have to change the medicine.” 604 Fish farmer F8 605 606 Some sought treatment recommendation and advice from more experienced peers, animal 607 husbandry personnel and from storekeepers who sold aquatic food and medicines. Farmers 608 occasionally referred to these sellers and personnel as ‘vets’; farmers would describe the 609 symptoms to the sellers and the sellers dispensed the medicines. Some stores also offered 610 water testing services. 611 612 “I asked the store owner too, and other people who used the same products or had 613 the same experiences. So, they can give me advice on what to do or what medicines 614 to use.” Fish farmer F3 615 616 “I would consult with people at the drug store. They usually have a veterinarian 617 there. Sometimes I would ask the veterinarians who can prescribe medicine that I 618 know. I would tell them the symptoms - such as having red scales, red gill and 619 droopy eyes - then ask which medicine I should use. They would give suggestions 620 based on that. We don’t meet face-to-face for the veterinarian to check the water 621 condition and tell us exactly which medicine we need to use specifically for such a 622 disease. I would be more sure like 100% if that is the case.” Fish farmer F8 623 624 Dedicated aquatic veterinary support was considered very rare in the area and farmers took 625 every opportunity to contact a veterinarian whenever one came into the neighbourhood, 626 though none of the farmers interviewed reported a veterinarian visiting their farms for routine . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 28 627 checks or in case of an illness or outbreak. One farmer said he had attended a training course 628 on aquatic farming, and another said they had done their own reading. 629 630 “At the beginning, I usually ask the agriculturist/academic. But after a while, I 631 started to study things myself. I tried different things while seeing what other 632 people use. That’s how I ended up with this product. Actually, others suggest me 633 to use Amoxy [amoxycillin] as well.” Fish farmer F6 634 635 “A fisheries scientist used to come to the district office, so I memorized the names 636 of the medications. I would call and asked him, whether this meds would work or 637 not, and he said that it can. So, I made the decision.” Fish farmer F6 638 639 “I attended training about fish diseases before. The instructor instructed us to use 640 which medicine with what symptom. I had the instructor’s phone number, so I used 641 to call him and ask him for the suggestion of medication relating to the fishes’ 642 symptom, but I lost the number.” Fish farmer F6 643 644 645 Socioecological influences in the development of aquaculture 646 Shifting land use from traditional rice farming to other agro-ventures including 647 aquafarming 648 Many participants described how land was, in the past, mainly used for rice farming and that 649 rice fields spread as far as the eye could see. Participants mentioned that, during the 1990s, . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 29 650 the use of land started to shift due to a fall in rice prices and subsequent economic loss. 651 Additionally, participants explained that the rice farming workforce has reduced over the 652 years due to aging with younger generations not wanting to undertake low-income 653 occupations. Subsequently, new business ventures started to appear. Factories were built and 654 other agricultural systems were promoted including gardening, plantations, aquaculture 655 farming and livestock farming to generate more income. 656 657 “Many people are doing the shrimp pond business because the income is good. 658 Those who cannot do the rice field will have shrimp ponds. The shrimp pond 659 business has been around for about 10 years because people had left the area and 660 when they came back, they started a shrimp pond business.” Fish farmer HH25 661 662 “Our family switched to raising fish in the old fields, digging old fields into fish 663 ponds. At that time, farming was not good. Oh, now farming requires a lot of 664 investment, a lot of things. My parents are old and I can't farm myself. So our 665 family has switched to raising fish instead.” Fish farmer HH25 666 667 668 “My family used to farm rice. I don't plant rice anymore, now I raise shrimp. In the 669 past, most of the rice fields were cultivated in this area, 80-90% of the area was 670 rice fields. Today it is transformed into a pond and mixed farming. It has changed 671 in the past 10 years from rice fields to shrimp ponds. However, when shrimp prices 672 are not good, there are farmers who turn back to rice farming. But my family has 673 always been raising shrimp since we have been raising shrimp and never changed. . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 30 674 I've raised white shrimp before. I planted Manila tamarind on the edge of the 675 shrimp pond, cultivated as an additional income. One year it can sell for over a 676 hundred thousand baht.” Shrimp farmer HH19 677 678 Economic fragility 679 All the households involved in aquaculture farming also had other sources of income. 680 Household members worked in various agriculture projects such as rice farming, growing 681 vegetables, fruit gardens, lotus ponds and aquaculture farming as well as livestock farming 682 including poultry and pigs. Other occupations such as working in factories and cookery were 683 also common. Participants explained that having different occupations provided more 684 financial stability to support families. For example, one household had to close their chicken 685 farm in 2006 due to avian influenza. However, they had other sources of income from raising 686 shrimp and growing rice as well as working as a truck driver. Another household, which had a 687 chicken farm contracted to sell eggs to a larger farm, closed the chicken egg business due to 688 lower egg prices being imposed by the larger farm. They had to sell all the chickens back to 689 the larger farm (from which they were originally purchased) at a financial loss. This household, 690 however, also had a tilapia pond they could rely on. One participant explained that the 691 concept of holding several farming projects was encouraged by the government-promoted 692 “sufficient economy” ideology which advocated the wise use of one’s own resources and the 693 redeployment rather than wasting of these resources. 694 695 “The people choose to do many kinds of agriculture because they might face a lack 696 of income if one of their businesses has some complications.” Shrimp farmer HH19 697 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 31 698 “My job is to raise fish and plant lotuses. My husband [HH227(02)] is the one who 699 picked up the lotus from the pond. I also help my husband. My other job is raising 700 my grandchildren… my husband will go out to feed the fish at 6 am. The pond has 701 tilapia and yisok [Julien’s golden carp]. Our ponds often sell fish to fishmongers 702 who sell fish in the fish market. They will come and catch fish at the pond 703 themselves.” Fish farmer HH27 704 705 “I repaired the equipment myself and also repaired the machines for other people 706 in the community.” Fish farmer HH27 707 708 “My house is sectioned according to the sufficiency economy’s prototype that is 709 the two rai areas [about 3800-6400 square meters] of the land is for the house, 710 various kinds of vegetable gardens, a fishpond and a pig shed. The rest of the land, 711 about 36 rai, is paddy field which is shared with other types of agriculture.” Fish 712 farmer HH38 713 714 Notably, most households were multi-generation residencies where grandparents, siblings 715 and grandchildren lived together in one house or adjacent houses on the same piece of land. 716 This concentration of family members provided labour for these multiple occupations. 717 Participants described helping each other in running different projects with stay-at-home 718 members (elderly, unemployed) generally helping with commercial cooking (restaurants, 719 catering) and aquaculture farming or livestock feeding. 720 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 32 721 “This fishpond belongs to my son. I couldn't do it, I let the kids feed the fish. When 722 catching fish for sale, there will be many relatives who are selling fish in the fish 723 market... We don't have to do anything. My son works at the university. He 724 returned on Saturday and Sunday. My daughter is a fish feeder… This pond is 725 raising tilapia, carp and yisok. It has been raised for 7-8 months.” Fish farmer HH03 726 727 728 729 Discussion 730 This study aimed to investigate the socio-economic and ecological conditions of freshwater 731 aquaculture farming and the drivers for AMU in a district in central Thailand. Our findings 732 demonstrated that there was limited use of antimicrobials across the farmers in this study. 733 Those farmers expressed doubt about the benefits of antimicrobials, both in relation to 734 disease treatment and aquatic animal growth. High cost and prohibitive market regulations 735 also discouraged farmers from using antimicrobials. Disease drivers were often linked to 736 weather changes, the emergence of new diseases and decreasing water quality due to 737 pollution. Farmers depended on improved farm management practices to maintain the health 738 of the aquatic animals; when that failed, many farmers applied emergency harvesting 739 techniques (i.e. no treatment but catching animals that were still alive). Aquaculture 740 veterinary support was limited in the area and many farmers relied on their social networks 741 and on experimenting with medicines in relation to decision making about disease treatment. 742 Aquaculture farms in this area took the shape of domestic ventures operated by family 743 members. These families were often found to invest in different juxtaposed small businesses . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 33 744 in an attempt to maintain or improve the financial stability of the household. Aquaculture 745 farming was considered a profitable business that did not require high input and labour. Initial 746 outlay was often reduced by repurposing unused crops, food or animal manure to fertilise the 747 ponds and stimulate aquatic animal growth instead of, or in addition to, using commercial 748 feed. 749 It is interesting that many farmers in this study stated that they did not use antimicrobials in 750 their farms. Farmers referred to antimicrobial treatments as ineffective and expensive. 751 Traditional antimicrobial administration methods are often problematic and complex in 752 aquaculture; dispensing antimicrobials directly into water or adding antimicrobials to aquatic 753 feed can be ineffective, possibly harmful and could lead to AMR [30-33]. This is due to 754 difficulties in adjusting a therapeutic dose uniformly across the pond, the effects of the 755 natural environment on the antimicrobial as well as associated toxicity (e.g. to denitrifying 756 bacteria leading to a build-up of toxic ammonia) [31]. Additionally, diseased fish often do not 757 eat, which reduces the success rate of medicating the feed [31]. Accordingly, specialist advice 758 is important to facilitate effective antimicrobial administration in aquaculture systems. It is 759 possible, therefore, that, in our study area, due to the lack of veterinary support, our 760 participants’ own attempts at antimicrobial treatment failed. This may have resulted in their 761 opinions about the lack of effectiveness of these drugs, which led them to stop using 762 antimicrobials and look for alternative disease management options. However, a few 763 participants still reported using antimicrobials despite limited observed benefit. Other studies 764 have noted that antimicrobial use may fluctuate from year to year even in the same area, 765 subject to changing climate and disease incidence; one review article noted that farmer 766 surveys often described inconsistent reports of antimicrobial use [34]. Another study in 767 Vietnam that monitored antimicrobial use found that although 45% of farmers believed . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 34 768 antimicrobials had no effect on curing diseases, 86% of the farmers who held that opinion still 769 used antibacterials for either treatment or prophylaxis [35]. These reports suggest that our 770 results indicating low use of antimicrobials should be interpreted with caution; although the 771 findings indicate little use, it would be valuable in our study area to see whether abstinence 772 from AMU continues into the future. Another relevant issue to AMR is the reported use of 773 fluoroquinolones in this study. One attraction of using fluoroquinolones in aquaculture is that 774 these molecules are stable in aquatic environments, rendering them easy to manage for 775 aquaculture disease treatment [36]. Indeed, enrofloxacin is widely used globally [24]. 776 However, the use of fluoroquinolones in aquaculture has been banned in many countries due 777 to their importance of some fluoroquinolones to human medicine (especially ciprofloxacin 778 and norfloxacin). This is because when resistance to one fluoroquinolone (whether used only 779 in farming, or used to treat animals and humans) emerges, it usually confers resistance to all 780 fluoroquinolones [15,24]. 781 782 Limited AMU in aquaculture, as was observed in this study, would broadly be considered 783 positive in relation to AMR; to ensure its sustainability, however, improving farm 784 management practice is also vital to compensate for the health needs of the aquatic animals 785 as well as to ensure farm biosecurity. Farmers in this study adopted several management 786 practices they considered important to protect their stock from diseases: pond preparation 787 and disinfection, healthy stock acquisition and good nutrition regimes, to name a few. These 788 farms resembled the description of the small-scale aquaculture farms described by the work 789 of Little et al. [10,37] which describes aquaculture as an activity practiced predominantly by 790 farmers “for whom aquaculture constitutes one element of a larger total livelihood portfolio”. 791 In these systems, farmers often adopt lower-input and lower-risk practices similar to . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 35 792 extensive farming systems. This is, for instance, by crop diversification, improving pond 793 preparation, choosing better-quality stock and using improved quality feed regimes, 794 subsequently reducing disease incidence and the need for treatment [38,39]. Similar multi- 795 culture agricultural systems such as home garden systems in Vietnam, Indonesia and Sri Lanka 796 have been encouraged for their socio-economic and ecological benefits, and have been 797 highlighted for their potential role in alleviating poverty [40-43]. In Thailand, the effects of 798 the extensification and the diversification of crops, as seen in our study area, has been shown 799 to lead to resilience in facing diseases (e.g. rotating rice and shrimp production showed 800 reduced disease susceptibility when compared to back-to-back shrimp farming) [13]. 801 Governmental support has also provided knowledge and production management plans 802 which have, in turn, encouraged farmers to establish mixed cropping agriculture [18]. Land 803 has often been divided into an area for the main farming activity, the secondary activity and 804 a supplementary activity, and has included plans for production of different types of plants, 805 livestock and fisheries [18]. Repurposing local resources such as we saw in in our study area 806 (e.g. using left-over crops and food to feed aquatic animals) has also been encouraged. 807 Another characteristic of Thai aquaculture farming was that farmers were seen to be well 808 connected to vertical and horizontal knowledge networks [44]. Their vertical network went 809 along the supply chain and also included government representatives, pharmaceutical and 810 feed companies. Farmers also belonged to social networks of interlinked farmer groups and 811 small clubs known locally as “Chum Rom”. These networks created a rural seminar culture 812 where farmers shared their knowledge and practices, and industry and government 813 representatives attended and added to discussions. 814 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 36 815 Despite improved management practices, findings of our study indicated that farmers were 816 still facing high disease and mortality rates among their aquatic animals. This could risk the 817 successful adaptation of extensive farming styles with low AMU, resulting in farmers 818 switching to more intensified farming practices with higher AMU [36,45]. Reasons for high 819 disease incidence were unclear but farmers cited water pollution as one of the drivers of 820 disease occurrence. The effects of water pollution on aquaculture farming have previously 821 been investigated in Thailand costal aquaculture regions [46,47]. These studies found that 822 aquaculture water quality was indeed affected by urban pollution in the canals and included 823 faecal coliforms, human Escherichia coli, tetracycline resistance genes and nitrogen [46]. The 824 aquaculture water was a source of salinity and herbicides. Additionally, high AMR prevalence 825 was found to be associated with a high prevalence of faecal indicator bacteria which was 826 highest in peri-urban canal water feeding the aquaculture systems [47]. Another study in 827 Taiwan investigated the potential cross-contamination problems between aquaculture 828 systems and surrounding waters [48]. This work demonstrated that aquaculture activities (i.e. 829 usage of antimicrobials) impacted the surrounding aquatic environments and, at the same 830 time, the surrounding anthropogenic activities impacted aquaculture waters. These studies 831 show that aquaculture (even with low AMU) would still be in danger of transmission of AMR 832 from the environment. Another factor potentially contributing to environmental AMR 833 transmission and selection in aquaculture systems is the use of animal manure in fertilising 834 the ponds [34,36], a practice applied by some of the farmers in our study. A few of these 835 even had integrated systems where manure was pumped from other animal sheds (e.g. pig 836 or chicken) to the ponds. This practice was seen by farmers as economically sustainable. 837 However, it is well established that manure is a reservoir of resistant bacteria and 838 antimicrobial compounds [49]. For example, in a study investigating the impact of integrated . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 37 839 fish farming (a practice combining livestock and fish farming, where animal manure is shed 840 directly into fish ponds) on AMR, the level of resistance in Acinetobacter spp. was found to 841 increase from 1-5% of bacterial isolates resistant prior to integration to 100% resistance to 842 oxytetracycline and sulfamethoxazole and to more than 80% resistance to ciprofloxacin after 843 two months [50]. Another study has shown the correlation between diffusion of 844 fluoroquinolone resistance genes and biofertilizers utilisation in Chinese shrimp aquaculture 845 [51]. There is certainly a need to raising awareness among aquaculture farmers of the risks of 846 using contaminated manure as well as the wider role of veterinary and husbandry support. 847 848 Another relevant finding linked to drivers of AMU was that participants linked disease 849 incidence to changes in climate, and particularly the effect of heat on fish health. Prophylactic 850 AMU was seen more commonly when farmers anticipated weather changes. Interestingly, 851 increased local temperature has been associated with increasing AMR in human infections 852 and this association was consistent across most classes of antibacterials and pathogen [52]. 853 Another study has found that increased temperature was associated with increased odds that 854 faecal samples from the environment were positive for resistant E. coli [53]. If AMR were also 855 to increase on fish farms as a function of temperature, it would be expected that 856 antimicrobials would then have reduced ability to cure bacterial infections in treated animals. 857 Increased temperature also affects the chemical activity and uptake of medicines in the pond 858 environment [30]. All these factors mean a possible increase in disease incidence on 859 aquaculture farms as the temperature rises, along with forward pressure on AMU, further 860 exacerbating AMR. There is a specific need, therefore, to support farmers in developing 861 disease management plans as the climate warms. 862 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 38 863 This study was a qualitative investigation, and the findings are specific to the research 864 geographical area and may not be generalisable to other geographical areas. Future studies 865 could include several areas with freshwater aquaculture. Farmers accounts of their use of 866 antimicrobials, disease incidence and mortality rates are subject to recall bias. 867 868 Conclusions 869 Farmers in this study reported limited AMU in small-scale family aquaculture farming due to 870 intentional and unintentional socio-economic and ecological factors. Governmental support 871 to encourage reduced disease risk and crop diversification as well as market regulation 872 concerning the residues of antimicrobials allowed in food may have encouraged farmers to 873 reduce their use of antimicrobials. Past experience of ineffective treatment of farmed aquatic 874 animals with antimicrobials and the high cost of these medicines have also played a part in 875 the low AMU reported. Increased disease rates were attributed to weather changes, the 876 emergence of new diseases and decreasing water quality due to pollution. The lack of 877 specialist aquatic veterinary support might leave farmers subject to pressure from 878 commercial drug sellers when they seek disease management advice and misuse may also 879 make treatment failure more likely, particularly as temperatures rise. There is a need to 880 investigate the effects of climate change on aquaculture farming across Southeast Asia as well 881 as its associated disease and treatments patterns. Further attention is needed to understand 882 and raise awareness about the risks of using contaminated animal manure in aquaculture 883 farming. Future policies should attempt to fill the gap in specialist veterinary provision to 884 freshwater aquaculture, address the need to provide evidence-based information and advice . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 39 885 on farm management practices that reduce the need for prophylactic and therapeutic AMU, 886 and particularly address disease prevention in the face of a changing climate. 887 888 Acknowledgements 889 We thank all the community members and the farmers who participated in this study. 890 . CC-BY 4.0 International licenseIt is made available under a perpetuity. is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint The copyright holder for thisthis version posted February 13, 2024. ; https://doi.org/10.1101/2024.02.11.24302655doi: medRxiv preprint 40 891 References 892 1. 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