Distribution of Snails species and its infectivity with Schistosomes at Mwanga District, North Eastern Tanzania.

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Seif Abdul, Ribson E. Mlaki, Emmanuel J. Awe, Petty J. Mzubwe, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5371989/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: Schistosomiasis, a parasitic disease caused by blood flukes, is still a public health problem in low-income countries like Tanzania. Of the 201 million people infected with schistosomiasis globally, 91% are in sub-Sahara Africa countries. In Tanzania, Mass Drug Administration (MDA) is one of the key interventions to control schistosomiasis, but rapid re-infection after treatment lead to persistent high prevalence of schistosomiasis in key groups like school-aged children. Snail control is an alternative, however there is limited information on epidemiology and interventions on snails that that transmit schistosomiasis in Tanzania. Methodology: A cross sectional study was conducted at Kileo ward in Mwanga District, from April-May 2019. The snails were collected manually using scooping technique and location where the snails were obtained was mapped by using Global Positioning System (GPS). Physico-chemical properties of water from each collection site were assessed using a multiparameter pH meter. The snails sampled at individual site were transferred to a laboratory for analysis within 4 hours of collection. The species and genus of snails were identified by shell morphology. Cercarial shedding was assessed over the first 48 hours after collection. Results: A total of 300 snails were collected from four different sites where people come into contact with water. The species of snails identified were Bulinus africanus (208) and Bulinus forskali (92). Snails of genus Biomphalaria were not identified among the collected snails. No snail was found to shed cercaria of schistosomiasis after being exposed to light. Conclusion: Finding of Bulinus spp support high occurrence of Schistosoma haematobium and in the area and the need for planning of snail control activities in this setting. There is a need to sample snails over a long period, in different seasons of the year, to map if there is season variability of snail species especially for those transmitting Schistosoma mansoni. Schistosomiasis Snail vector Cercarial shedding Kilimanjaro Tanzania. Figures Figure 1 Figure 2 Background Schistosomiasis is a parasitic disease caused by blood flukes (trematodes worms) of the genus Schistosoma. There are five genus of Schistosoma that infects humans, but Schistosoma haematobium (urogenital) and Schistosoma mansoni (intestinal) are common types in Tanzania and Africa. The transmission occurs when infected people contaminate water with schistosome eggs from urine and/or stool, the eggs hatch into miracidium stage, which infects the snails. Various factors exert an influence upon infection of snail by miracidia, including: the age of the snail and miracidia, the number of miracidia per snail, the temperature of exposure and the temperature at which the snail is maintained during the pre-patient period. People become infected when the larval form (cercaria) of the parasites released by fresh water snails penetrate the skin during contact with infested water (WHO, 2018). The infected snail in presence of sunlight release cercaria that swims and penetrate the skin of human host when come in contact with water containing cercaria. After penetration cercaria develop into adult worm in blood vessel (veins) of the intestinal or urinary tract system. Snails are considered to be an important intermediate host because human harbor the sexual stages of the parasites and snails harbor the asexual stages. It is estimated that 779 million people globally are at risk of schistosomiasis where by 106 million live in the irrigation scheme or close to fresh water bodies such as dams used in irrigation (Steinmann et al ., 2006). An estimated 250 million people in 78 countries are infected with schistosomiasis of which 85% live in Sub-Sahara Africa (Sacolo et al., 2018). Sub-Sahara Africa has highest burden schistosomiasis with 120 million individuals who are infected, 20 million having chronic presentation of the disease (Adewo et al. 2015 ). In Sub-Sahara Africa schistosomiasis is attributed by two species namely S. mansoni and S. haematobium . In Tanzania about 23,189,294 out of 43.5 million people were estimated to be infected of schistosomiasis equal to prevalence of 51.5% in 2012. The World Health organization has set goals of controlling morbidity to be reached by 2020, along with elimination as a public health problem in certain regions by 2025. Snails are slow moving gastropods living on land or in water and having spiral protective shell. Snails are considered to be intermediate host because they harbor the asexual stage of the parasite while human being is a definitive host because harbors the sexual stage of the parasite (Ting Lu, et al ., 2018). Without snails, the transmission of schistosomiasis cannot be sustained, thus snail control will contribute in decreasing the burden of disease. There are four main species of snails that are considered to be of medical importance for transmission of schistosomiasis.The genera that are main in sub-Sahara Africa are Biomphalaria, Bulinus, Oncomelania and Tricula , by which they are divided into two groups as acquatic snails ( Biomphalaria and Bulinus ) and amphibious snails which are adapted for living in and out of water ( Oncomelania ). Distribution of snails causing schistosomiasis differs in Tanzania. The main species of Biomphalaria snails important in transmission of schistosoma mansoni and found in Tanzania are B. choanomphala , B. pfeifferi, B. sudanica and Biomphalaria angulosa. Biomphalaria choanomphala restricted only to large water bodies (Lake Victoria), Biomphalaria pfeifferi is found in all regions of mainland part of the country except eastern coastal region, Unguja and Pemba. Biomphalaria sudanica is found in all regions of mainland part of the country except central region of Dodoma, Singida, the eastern and southern coastal region, Unguja and Pemba. And Biomphalaria angulosa common in lower lands and highlands southern (Mazigo et al ., 2012) Bulinus species are important in transmission of S. haematobium . Species distributions differ in different parts of Tanzania. Bulinus globosus is found in Unguja, Pemba and in mainland Tanzania while Bulinus nasutus (for S. haematobium & S. bovis ) is found in Pemba, Mafia is land and all region of mainland parts of the country. Bulinus africanusafricanus (for S . haematobium and S . bovis ) is distributed in all the region of Tanzania. Bulinus forskalii is probably distributed in all regions of mainland part of the country and Mafia Island (Mazigo et al ., 2012). WHO recommend and put forward recently ambitious goals for the year 2020 to control schistosomiasis globally and all countries should have schistosomiasis prevalence of less than 5% among school-aged children. The interruption of transmission and elimination of schistosomiasis should be encouraged when ever resources allow (Knopp et al ., 2013). Mass Drug Administration (MDA) and education have been two interventions used by most Sub-Sahara Africa countries including Tanzania to reduce schistosomiasis morbidity (WHO, 2018). However these efforts without snail control efforts have led to still high burden of disease in Africa and Tanzania. Despite the application of molluscicides and biological control to reduced snail population that has been done in some places in Tanzania over time, vector (snail) control has been forgotten, and has not received the same emphasis like MDA in schistosomiasis control. The establishment of chemotherapy campaigns (mass drug administration to at risk populations) did not go hand-to-hand with snails control in the country. There is therefore limited information on snails distribution and infectivity patterns hence there is a need to have an information which guide the presence of intermediate hosts, their distribution and infectivity potential. The information may contribute in vector control activities to achieve control of schistosomiasis properly. Methods Study area Field work was conducted at Kileo in Mwanga district. Mwanga is the one of the seven districts of the Kilimanjaro region in northeast Tanzania. It is bordered to the northeast by Kenya, to the northwest by the Moshi rural, to the southwest by the Manyara region, and to the south by the Same district. The Mwanga district is administratively divided into 16 wards, Kileo being among them. Kileo ward is situated at 726.00m from sea level. Kileo ward has the total population of 13,645 according to 2012. The ward has two villages; Kileo and Kivulini. The most economical activity in the area is rice cultivation through traditional irrigation scheme. In addition, people cultivate vegetables and fishing. All these are facilitated by presence of Kileo forest where two streams (Gona and Ruvu) originates, providing water throughout the year. Such environmental factors facilitate the presence of snails that transmit schistosomiasis. Malacology Procedure The snails were selected in four different sites (A, B, C and D) during April 2019 in Kileo village. The sites were selected based on human-water contact. Scooping technique-using scoops, hand sieves and forceps were used to collect the snails manually. The snails sampled at individual sites was stored in container filled with water depend on size and number of snails from the originating and transferred to laboratory. The snail samples were kept at room temperature (24-27 o C) at pH of 6.7. The containers were labeled according to site of collection, date of collection and numbered. In the laboratory snails were kept alive in covered water tanks at room temperature using water from the original source without chlorination. The types of vegetation cover and presence or absence of algal mass in each sampling site was recorded. Physico-chemical characteristics of the water at each sampling site was determined including a multiparameter pH meter (Eutech PCSTEST35-01X441506/Oakton 35,425–10, Vernon Hills, Illinois, 60,061, USA) based on guidelines provided by the manufacturer. The location where the snail obtained was mapped by using Global Positioning System. All habitats where the snails sampled were mapped by Global Positioning System (GPS) using hand-held GPS unit. Sample was carried out by two trained field collectors using standard snail scoops. The same collectors scooped for snails throughout so as to achieve same level of standardized sampling effort. In rice paddies where the water was very shallow, the snails were picked directly using foreceps. The sampling was fixed at 30 minutes per location and was performed between 8:30 am and 10:30 am. At each collection time, snails from sites were labeled and transported in perforated falcon tube separately to the laboratory for investigation. (Photo 1.) Laboratory methods Laboratory procedures were carried at KCMUCo parasitology laboratory. Daily, snails were separated soon after arrival in laboratory. Brown Standard keys of Brown (1994) and DBL-WHO (1998) were used to identify the snails, based on the characteristics of shell morphology. The cercarial shedding was assessed over the first 48 hours after collection. Snails were rinsed using tape water, then inspected for infection by placing them beakers with 10mls of tap water followed by exposure to light for 3 hours. After exposure, the water was examined under dissection microscope for presence of schistosoma cercaria. The snails that did not shed cercaria were exposed in the following day for cercarial shedding. Results Species of snails 300 snails were collected from four different sites where people come to contact with water. The species of snails collected were Bulinus africanus (180) and Bulinus forskali (120). (Photo 2) Infectivity of snails No snail was found to shed cercaria of schistosomiasis after being exposed to light. Distribution of snail species The snails where collected from four site named A, B, C and D. All four areas were covered with algae and vegetation. Site A was in Kivulini canal containing water at 25 0 C where both Bulinus africanus and Bulinus forskali where found. The site B containing water of 27 0 C, in this site we found only bulinus africanus in rice paddies with water from Bogoyo canal. The site C was with water of 24 0 C near the water spring (Mtindi forest). In this site we found Bulinus forskali and few Bulinus africanus. The site D was located with water of 28 0 C. This was flooded area forming a breeding site. In this area we found only Bulinus africanus. It seems that Bulinus africanus prefer high temperature than Bulinus forskali. (Table 1) Table 1: Distribution of snail species (N=75) SITE n % Site A Bulinus africanus 27 36 Bulinus forskali 48 64 Site B Bulinus africanus 75 100 Bulinus forskali 0 0 Site C Bulinus africanus 3 4 Bulinus forskali 72 96 Site D Bulinus africanus 75 100 Bulinus forskali 0 0 DISCUSSION The study investigated distribution of snails that transmit schistosomiasis and its infectivity at Kileo, Mwanga district northeastern Tanzania. Two species of snail found were Bulinus africanus and Bulinus forskali. Snails were tested for cercaria shedding but none of the species was found to shed cercaria. Snails were found distributed in all area of slow moving water covered with vegetation and algae. In rice paddies with water from Bogoyo canal (site B) and in flooded area (site D) only Bulinus africanus species were found. Near the water spring (site C) and Kivulini canal both Bulinus forskali and Bulinus africanus were found but B. forskali dominating the areas. The average characteristics of water pH was 7.35 and the temperature was 26 0 C. In Gombe National Park, nearby village and Kigoma in western Tanzania total of 235 snails were collected from stream close to human settlement. Snails were individually exposed to light to induce shedding of cercaria, which was examined using compound light microscope. None of the snails from Gombe or Bugamba was shedding cercaria, were prevalence of cercaria shedding from the snail of other region (Kiziba Mtanga Mwamgongo and Bugamba) was 12%. Some snail which were not shedding cercaria were PCR positive for the 500 base pair Internal Transcribed Spacer (ITS) which was predicted to indicate infection with schistosomiasis (Bakuza et al ., 2017). Further study is needed to test the infectivity of the snails in different season of the year because snails were sampled within short period (1month) hence the seasonal variation of snail’s distribution and infectivity with Schistosoma was not captured. Declarations Manuscript trial number Not applicable Ethical approval and consent to participate Ethical approval to carry out the current study was obtained from Kilimanjaro Christian Medical College Research Ethics and Review Committee (KCMU-CREC) with clearance number UG. 23/2019. Consent for publication Not applicable. Ethical clearance serves both purposes. Availability of Data and Materials All data and materials concerning this research article are available for sharing if needed. Competing interests All authors have no competing interests on the findings of this study Funding No funding was used in this study Authors’ contributions SA – develop the concept design the methodology, conducted data analysis and wrote the manuscript. REM, EJA, and PJM – develop the concept, conducted data collection and participate in data analysis VVM– conducted data analysis and manuscript writing JM – Review the manuscript SEM – review the concept, methodology design and data analysis Acknowledgements Our sincere acknowledgement goes to KCMUCo and specifically the Institute of public health for making this piece of work easier. We also acknowledge the Mwanga district council through Distric medical officer’s office for allow us to conducted data analysis in the district. References Abou-EL-Naga IF, (2018). ‘Towards elimination of schistosomiasis after 5000 years of endemicity in Egypt’ Acta Tropica 181:112-121 Adewo AF, (2015). ‘Impact of Schistosomiasis in Sub-Sahara Africa’ Brazilian Journal of Infectious Disease 19 (2): 196-205. Allan F, Sousa-Figueiredo JC, Emery AM, Paulo R, Mirante C, Sebastiao A, et al .,(2017). 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Madsen H, (1983) ‘Distribution of Helisoma duryi, an introduced competitor of intermediate hosts of schistosomiasis, in an irrigation scheme in northern Tanzania’. Acta Tropical 40(3):297-306. Mazigo, H.D, 2012.'Epidemiology and control of schistosomiasis in Tanzania'. Parasites and Vectors 5:274. Nguma JF, McCullough FS, and Masha E. (1982). ‘Elimination of Biomphalaria pfeifferi , Bulinus tropicus and Lymnaea natalensis by the ampullarid snail, Marisa cornuarietis , in man-made dam in northen Tanzania’. Acta Tropical 39(1):85-90. Opisa S, Odiere MR, Jura WG, Karanja DMS and Mwinzi PNM (2011). ’Malacological survey and geographical distribution of vector snails for schistosomiasis within informal settlement of Kisumu City, Western Kenya’ Parasites and Vectors 4:226 doi.org/10.1186/1756-3305-4-226. Poggensee G, Krantz I, Nordin P, Mtweve S, Ahlberg B, Mosha G, et al., (2005), ‘ A six year follow-up of schoolchildren for urinary and intestinal schistosomiasis and soil- transmitted helminthiasis in Northern Tanzania’ Acta Tropica , 93(2): 131-40. Pointer JP and Jourdane, (2000), ‘Biological control of the snail hosts of schistosomiasis in areas of low transmission: The example of the Caribbean area. Acta Tropica 77(1):53-60. Sacolo H, Chimbari M and Kalinda C, (2018), ‘Knowledge, attitudes and practices on schistosomiasis in Sub-Sahara Africa’ BMC Infectious Diseases 18(1): 46.doi:10.1186/s12879-017-2923-6. Sun L, Wang w, Hong Q-B, Li S-Z, Liang Y-S, Yang H-T et al., (2017) ‘Approaches being used in the national schistosomiasis elimination programme in China’ Infectious Diseases of Poverty 6:55 doi 10.1186/s40249-017-0271-9 . Ting Lu X, GuQY, Limpanont Y, Song LG, Wu ZD, Okanurak K et al., (2018) 'An update on global epidemiological distribution, transmission interruption and control methods. Infectious Diseases of Poverty 7(1): 28. World Health Organization,( 2018), ‘Schistosomiasis’ www.who.int/schistosomiasis/disease/en/ 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. 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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-5371989","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":376845771,"identity":"549f98ab-7925-431c-809c-8c63b9d5bac8","order_by":0,"name":"Seif Abdul","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYDACCQYDhgcMDDwMEswHQFwZ4rQkgLWwJYC4PERrASk2AFGEtfDPbt4mkVBjI2Mu3fP51Y0aCx4G9sNHN+C15M6xMomEY2k8lnPObrPOOQZ0GE9a2g281tzIMZNIbDjMY3Ajd5txDhtQiwSPGV4t8hAt/4Facp4Z5/wjQosBRMsBkBbmx7ltRGgxvHOs2CLhWDKP5Yw0M+bcPgkeNkJ+kbvdvPHGhxo7e3OJ5Mefc77VyfGzHz6G3/twFzIwsEmAGGxEKYdqYf5AtOpRMApGwSgYUQAAYNBF+onGBBYAAAAASUVORK5CYII=","orcid":"","institution":"National Public Health Laboratory","correspondingAuthor":true,"prefix":"","firstName":"Seif","middleName":"","lastName":"Abdul","suffix":""},{"id":376845772,"identity":"f7d30f8a-5c8a-40e7-a107-80411d45b267","order_by":1,"name":"Ribson E. 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There are five genus of Schistosoma that infects humans, but \u003cem\u003eSchistosoma haematobium\u003c/em\u003e (urogenital) and \u003cem\u003eSchistosoma mansoni\u003c/em\u003e (intestinal) are common types in Tanzania and Africa. The transmission occurs when infected people contaminate water with schistosome eggs from urine and/or stool, the eggs hatch into miracidium stage, which infects the snails. Various factors exert an influence upon infection of snail by miracidia, including: the age of the snail and miracidia, the number of miracidia per snail, the temperature of exposure and the temperature at which the snail is maintained during the pre-patient period. People become infected when the larval form (cercaria) of the parasites released by fresh water snails penetrate the skin during contact with infested water (WHO, 2018). The infected snail in presence of sunlight release cercaria that swims and penetrate the skin of human host when come in contact with water containing cercaria. After penetration cercaria develop into adult worm in blood vessel (veins) of the intestinal or urinary tract system. \u0026nbsp; Snails are considered to be an important intermediate host because human harbor the sexual stages of the parasites and snails harbor the asexual stages.\u003c/p\u003e\n\u003cp\u003eIt is estimated that 779 million people globally are at risk of schistosomiasis where by 106 million live in the irrigation scheme or close to fresh water bodies such as dams used in irrigation (Steinmann \u003cem\u003eet al\u003c/em\u003e., 2006). An estimated 250 million people in 78 countries are infected with schistosomiasis of which 85% live in Sub-Sahara Africa (Sacolo \u003cem\u003eet al.,\u0026nbsp;\u003c/em\u003e2018). Sub-Sahara Africa has highest burden schistosomiasis with 120 million individuals who are infected, 20 million having chronic presentation of the disease (Adewo \u003cem\u003eet al. 2015\u003c/em\u003e). In Sub-Sahara Africa schistosomiasis is attributed by two species namely S. \u003cem\u003emansoni and\u0026nbsp;\u003c/em\u003eS. \u003cem\u003ehaematobium\u003c/em\u003e. \u0026nbsp;In Tanzania about 23,189,294 out of 43.5 million people were estimated to be infected of schistosomiasis equal to prevalence of 51.5% in 2012. The World Health organization has set goals of controlling morbidity to be reached by 2020, along with elimination as a public health problem in certain regions by 2025.\u003c/p\u003e\n\u003cp\u003eSnails are slow moving gastropods living on land or in water and having spiral protective shell. Snails are considered to be intermediate host because they harbor the asexual stage of the parasite while human being is a definitive host because harbors the sexual stage of the parasite (Ting Lu, \u003cem\u003eet al\u003c/em\u003e., 2018). Without snails, the transmission of schistosomiasis cannot be sustained, thus snail control will contribute in decreasing the burden of disease.\u003c/p\u003e\n\u003cp\u003eThere are four main species of snails that are considered to be of medical importance for transmission of schistosomiasis.The genera that are main in sub-Sahara Africa are \u003cem\u003eBiomphalaria, Bulinus, Oncomelania and Tricula\u003c/em\u003e, by which they are divided into two groups as acquatic snails (\u003cem\u003eBiomphalaria and Bulinus\u003c/em\u003e) and amphibious snails which are adapted for living in and out of water (\u003cem\u003eOncomelania\u003c/em\u003e).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDistribution of snails causing schistosomiasis differs in Tanzania. The main species of Biomphalaria snails important in transmission of schistosoma mansoni and found in Tanzania are \u003cem\u003eB. choanomphala\u003c/em\u003e, \u003cem\u003eB. pfeifferi, B. sudanica\u0026nbsp;\u003c/em\u003eand\u003cem\u003e\u0026nbsp;Biomphalaria angulosa. Biomphalaria choanomphala\u003c/em\u003erestricted only to large water bodies (Lake Victoria), \u003cem\u003eBiomphalaria pfeifferi\u0026nbsp;\u003c/em\u003eis found in all regions of mainland part of the country except eastern coastal region, Unguja and Pemba. \u003cem\u003eBiomphalaria sudanica\u0026nbsp;\u003c/em\u003eis found in all regions of mainland part of the country except central region of Dodoma, Singida, the eastern and southern coastal region, Unguja and Pemba. And \u003cem\u003eBiomphalaria angulosa\u0026nbsp;\u003c/em\u003ecommon in lower lands and highlands southern (Mazigo \u003cem\u003eet al\u003c/em\u003e., 2012)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eBulinus\u0026nbsp;\u003c/em\u003especies are important in transmission of \u003cem\u003eS. haematobium\u003c/em\u003e. Species distributions differ in different parts of Tanzania. \u003cem\u003eBulinus globosus\u003c/em\u003e is found in Unguja, Pemba and in mainland Tanzania while \u003cem\u003eBulinus nasutus\u003c/em\u003e (for \u003cem\u003eS. haematobium\u0026nbsp;\u003c/em\u003e\u0026amp; S. \u003cem\u003ebovis\u003c/em\u003e) is found in Pemba, \u0026nbsp;Mafia is land and all region of mainland parts of the country. \u003cem\u003eBulinus africanusafricanus\u003c/em\u003e (for \u003cem\u003eS\u003c/em\u003e. \u003cem\u003ehaematobium\u0026nbsp;\u003c/em\u003eand \u003cem\u003eS\u003c/em\u003e. \u003cem\u003ebovis\u003c/em\u003e) is distributed in all the region of Tanzania.\u003cem\u003e\u0026nbsp;Bulinus forskalii\u0026nbsp;\u003c/em\u003eis probably distributed in all regions of mainland part of the country and Mafia Island (Mazigo \u003cem\u003eet al\u003c/em\u003e., 2012).\u003c/p\u003e\n\u003cp\u003eWHO recommend and put forward recently ambitious goals for the year 2020 to control schistosomiasis globally and all countries should have schistosomiasis prevalence of less than 5% among school-aged children. The interruption of transmission and elimination of schistosomiasis should be encouraged when ever resources allow (Knopp \u003cem\u003eet al\u003c/em\u003e., 2013). \u0026nbsp;Mass Drug Administration (MDA) and education have been two interventions used by most Sub-Sahara Africa countries including Tanzania to reduce schistosomiasis morbidity (WHO, 2018). However these efforts without snail control efforts have led to still high burden of disease in Africa and Tanzania.\u003c/p\u003e\n\u003cp\u003eDespite the application of molluscicides and biological control to reduced snail population that has been done in some places in Tanzania over time, vector (snail) control has been forgotten, and has not received the same emphasis like MDA in schistosomiasis control. The establishment of chemotherapy campaigns (mass drug administration to at risk populations) did not go hand-to-hand with snails control in the country. There is therefore limited information on snails distribution and infectivity patterns hence there is a need to have an information which guide the presence of intermediate hosts, their distribution and infectivity potential. The information may contribute in vector control activities to achieve control of schistosomiasis properly.\u003c/p\u003e"},{"header":"Methods","content":"\u003ch3\u003eStudy area\u003c/h3\u003e\n\u003cp\u003eField work was conducted at Kileo in Mwanga district. Mwanga is the one of the seven districts of the Kilimanjaro region in northeast Tanzania. It is bordered to the northeast by Kenya, to the northwest by the Moshi rural, to the southwest by the Manyara region, and to the south by the Same district. The Mwanga district is administratively divided into 16 wards, Kileo being among them. Kileo ward is situated at 726.00m from sea level.\u003c/p\u003e\n\u003cp\u003eKileo ward has the total population of 13,645 according to 2012. The ward has two villages; Kileo and Kivulini. The most economical activity in the area is rice cultivation through traditional irrigation scheme. In addition, people cultivate vegetables and fishing. All these\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eare facilitated by presence of Kileo forest where two streams (Gona and Ruvu) originates, providing water throughout the year. Such environmental factors facilitate the presence of snails that transmit schistosomiasis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMalacology Procedure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe snails were selected in four different sites (A, B, C and D) during April 2019 in \u0026nbsp;Kileo village. The sites were selected based on human-water contact. Scooping technique-using scoops, hand sieves and forceps were used to collect the snails manually. The snails sampled at individual sites was stored in container filled with water depend on size and number of snails from the originating and transferred to laboratory. The snail samples were kept at room temperature (24-27 \u003csup\u003eo\u003c/sup\u003eC) at pH of 6.7.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe containers were labeled according to site of collection, date of collection and numbered. In the laboratory snails were kept alive in covered water tanks at room temperature using water from the original source without chlorination.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe types of vegetation cover and presence or absence of algal mass in each sampling site was recorded. \u0026nbsp;Physico-chemical characteristics of the water at each sampling site was determined including a multiparameter pH meter (Eutech PCSTEST35-01X441506/Oakton\u003c/p\u003e\n\u003cp\u003e35,425\u0026ndash;10, Vernon Hills, Illinois, 60,061, USA) based on guidelines provided by the manufacturer.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The location where the snail obtained was mapped by using Global Positioning System. All habitats where the snails sampled were mapped by Global Positioning System (GPS) using hand-held GPS unit.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Sample was carried out by two trained field collectors using standard snail scoops. The same collectors scooped for snails throughout so as to achieve same level of standardized sampling effort. In rice paddies where the water was very shallow, the snails were picked directly using foreceps. The sampling was fixed at 30 minutes per location and was performed between 8:30 am and 10:30 am. At each collection time, snails from sites were labeled and transported in perforated falcon tube separately to the laboratory for investigation. \u003cstrong\u003e(Photo 1.)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003c/strong\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLaboratory methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLaboratory procedures were carried at KCMUCo parasitology laboratory. Daily, snails were separated soon after arrival in laboratory. Brown Standard keys of Brown (1994) and DBL-WHO (1998) were used to identify the snails, based on the characteristics of shell morphology. The cercarial shedding was assessed over the first 48 hours after collection. Snails were rinsed using tape water, then inspected for infection by placing them beakers with 10mls of tap water followed by exposure to light for 3 hours. After exposure, the water was examined under dissection microscope for presence of \u003cem\u003eschistosoma\u003c/em\u003e cercaria. The snails that did not shed cercaria were exposed in the following day for cercarial shedding.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eSpecies of snails\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e300 snails were collected from four different sites where people come to contact with water. The species of snails collected were \u003cem\u003eBulinus africanus\u0026nbsp;\u003c/em\u003e(180) and \u003cem\u003eBulinus forskali\u0026nbsp;\u003c/em\u003e(120). \u003cstrong\u003e(Photo 2)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInfectivity of snails\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo snail was found to shed cercaria of schistosomiasis after being exposed to light.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDistribution of snail species\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe snails where collected from four site named A, B, C and D. All four areas were covered with algae and vegetation. Site A was in\u0026nbsp;Kivulini canal containing water at 25\u003csup\u003e0\u003c/sup\u003eC where both \u003cem\u003eBulinus africanus\u003c/em\u003e and \u003cem\u003eBulinus forskali\u0026nbsp;\u003c/em\u003ewhere found. The site B containing water of 27\u003csup\u003e0\u003c/sup\u003eC, in this site we found only \u003cem\u003ebulinus africanus\u0026nbsp;\u003c/em\u003ein\u003cem\u003e\u0026nbsp;\u003c/em\u003erice paddies with water from Bogoyo canal. The site C was with water of 24\u003csup\u003e0\u003c/sup\u003eC near the water spring (Mtindi forest). In this site we found \u003cem\u003eBulinus forskali\u0026nbsp;\u003c/em\u003eand few \u003cem\u003eBulinus africanus.\u0026nbsp;\u003c/em\u003eThe site D was located with water of 28\u003csup\u003e0\u003c/sup\u003eC. This was flooded area forming a breeding site. In this area we found only \u003cem\u003eBulinus africanus.\u0026nbsp;\u003c/em\u003eIt seems that \u003cem\u003eBulinus africanus\u0026nbsp;\u003c/em\u003eprefer high temperature than\u003cem\u003e\u0026nbsp;Bulinus forskali.\u0026nbsp;\u003c/em\u003e\u003cstrong\u003e(Table 1)\u003c/strong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 1: Distribution of snail species (N=75)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSITE\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u003cstrong\u003en\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e%\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003eSite A\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus africanus\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus forskali\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003eSite B\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus africanus\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus forskali\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003eSite C\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus africanus\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus forskali\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003eSite D\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus africanus\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 47.0882%;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003cem\u003eBulinus forskali\u003c/em\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 26.4559%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDISCUSSION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study investigated distribution of snails that transmit schistosomiasis and its infectivity at Kileo, Mwanga district northeastern Tanzania. Two species of snail found were \u003cem\u003eBulinus africanus\u003c/em\u003e and \u003cem\u003eBulinus forskali.\u0026nbsp;\u003c/em\u003eSnails were tested for cercaria shedding but none of the species was found to shed cercaria.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSnails were found distributed in all area of slow moving water covered with vegetation and algae. In rice paddies with water from Bogoyo canal (site B) and in flooded area (site D) only \u003cem\u003eBulinus africanus\u003c/em\u003e species were found. Near the water spring (site C) and Kivulini canal both \u003cem\u003eBulinus forskali\u0026nbsp;\u003c/em\u003eand \u003cem\u003eBulinus africanus\u0026nbsp;\u003c/em\u003ewere found but B. \u003cem\u003eforskali\u0026nbsp;\u003c/em\u003edominating the areas. The average characteristics of water pH was 7.35 and the temperature was 26\u003csup\u003e0\u003c/sup\u003eC.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn Gombe National Park, nearby village and Kigoma in western Tanzania total of 235 snails were collected from stream close to human settlement. Snails were individually exposed to light to induce shedding of cercaria, which was examined using compound light microscope. None of the snails from Gombe or Bugamba was shedding cercaria, were prevalence of cercaria shedding from the snail of other region (Kiziba Mtanga Mwamgongo and Bugamba) was 12%. Some snail which were not shedding cercaria were PCR positive for the 500 base pair Internal Transcribed Spacer (ITS) which was predicted to indicate infection with schistosomiasis (Bakuza \u003cem\u003eet al\u003c/em\u003e., 2017). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFurther study is needed to test the infectivity of the snails in different season of the year because snails were sampled within short period (1month) hence the seasonal variation of snail\u0026rsquo;s distribution and infectivity with Schistosoma was not captured.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eManuscript trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval to carry out the current study was obtained from Kilimanjaro Christian Medical College Research Ethics and Review Committee (KCMU-CREC) with clearance number \u003cstrong\u003eUG. 23/2019.\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. Ethical clearance serves both purposes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data and Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data and materials concerning this research article are available for sharing if needed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have no competing interests on the findings of this study\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was used in this study\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSA \u0026ndash; develop the concept design the methodology, conducted data analysis and wrote the manuscript.\u003c/p\u003e\n\u003cp\u003eREM, EJA, and PJM \u0026ndash; develop the concept, conducted data collection and participate in data analysis\u003c/p\u003e\n\u003cp\u003eVVM\u0026ndash; conducted data analysis and manuscript writing\u003c/p\u003e\n\u003cp\u003eJM \u0026ndash; Review the manuscript\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSEM \u0026ndash; review the concept, methodology design and data analysis\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOur sincere acknowledgement goes to KCMUCo and specifically the Institute of public health for making this piece of work easier. We also acknowledge the Mwanga district council through Distric medical officer\u0026rsquo;s office for allow us to conducted data analysis in the district.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbou-EL-Naga IF, (2018). \u0026lsquo;Towards elimination of schistosomiasis after 5000 years of \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; endemicity in Egypt\u0026rsquo; \u003cem\u003eActa Tropica \u003c/em\u003e181:112-121\u003c/li\u003e\n\u003cli\u003eAdewo AF, (2015). \u0026lsquo;Impact of Schistosomiasis in Sub-Sahara Africa\u0026rsquo; \u003cem\u003eBrazilian Journal of\u0026nbsp;\u0026nbsp;\u003c/em\u003e\u003cem\u003eInfectious Disease\u003c/em\u003e19 (2): 196-205.\u003c/li\u003e\n\u003cli\u003eAllan F, Sousa-Figueiredo JC, Emery AM, Paulo R, Mirante C, Sebastiao A, \u003cem\u003eet al\u003c/em\u003e.,(2017). 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Freshwater Snails of Africa and their Medical Importance, 2nd ed., Taylor \u0026amp; Francis Ltd., England, 609 pp.-\u003c/li\u003e\n\u003cli\u003eChantima K, Suk-Ueng K, Kampan M, (2018). \u0026lsquo;Freshwater snail Diversityin Mae Lao agriculture basin (Chiang Rai, Thailand) with a focus on larval trematode infection\u0026rsquo; \u003cem\u003eKorean Journal of Parasitol\u003c/em\u003eo\u003cem\u003egy\u003c/em\u003e56(3): 247-257.\u003c/li\u003e\n\u003cli\u003eDida G.O, Gelder F.B, Anyona D.N, Matano A.S, Abuom P.O, Adoka S.O \u003cem\u003eet al\u003c/em\u003e., (2014).\u003c/li\u003e\n\u003cli\u003e\u0026lsquo;Distribution and abundance of schistosomiasis and fasciolasis host snails along the Mara River in Kenya and Tanzania\u0026rsquo; \u003cem\u003eInfectious Ecol Epidimiology.\u003c/em\u003e 4: 10.3402/iee.v4.24281.\u003c/li\u003e\n\u003cli\u003eEddine Z.R, Djuikwo-Teukeng F.F, Al-jawhari M, Senghor B, Huyse T. \u003cem\u003eet al\u003c/em\u003e., (2014)'Phylogeny of seven bulinus species originating from endemic areas in three African countries, in relation to the human blood fluke \u003cem\u003eSchistosoma haematobium' BMC evolutionary biology\u003c/em\u003e 14:271 doi.org/10.1186/s12862-014-0271-3.\u003c/li\u003e\n\u003cli\u003eFenwick A and Lidgate HJ, (1970), \u0026lsquo;attempt to eradicate snails from impounded water by the use of N-tritylmorpholine \u003cem\u003e\u0026rsquo;Bullen of World Health Organization\u003c/em\u003e, 42(4): 581-8.\u0026nbsp;\u0026nbsp;\u003c/li\u003e\n\u003cli\u003eGouvrasAN,Allan F, Kinung\u0026rsquo;hi S, RaboneM,Emery A, Angelo T, Pennance T, Webster B, Nagai H, Rollinson D, (2017). \u0026lsquo;Longitudinal survey on the distribution of \u003cem\u003eBiomphalaria\u0026nbsp; sudanica\u003c/em\u003e and B. \u003cem\u003echoanomophala\u003c/em\u003e in Mwanza region, on the shore of lake Victoria Tanzania \u003cem\u003eParasite and Vectors\u003c/em\u003e 10:316 doi.org/10.1186/s13071-017-2252-z.\u003c/li\u003e\n\u003cli\u003eKristensens, T. 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(1982). \u0026lsquo;Elimination of \u003cem\u003eBiomphalaria pfeifferi\u003c/em\u003e,\u0026nbsp;\u003cem\u003eBulinus tropicus\u003c/em\u003e and \u003cem\u003eLymnaea natalensis\u003c/em\u003e by the ampullarid snail, \u003cem\u003eMarisa cornuarietis\u003c/em\u003e, in man-made dam in northen Tanzania\u0026rsquo;. \u003cem\u003eActa Tropical\u003c/em\u003e 39(1):85-90.\u003c/li\u003e\n\u003cli\u003eOpisa S, Odiere MR, Jura WG, Karanja DMS and Mwinzi PNM (2011). \u0026rsquo;Malacological survey and geographical distribution of vector snails for schistosomiasis within informal settlement of Kisumu City, Western Kenya\u0026rsquo;\u003cem\u003e Parasites and Vectors\u003c/em\u003e 4:226 doi.org/10.1186/1756-3305-4-226.\u003c/li\u003e\n\u003cli\u003ePoggensee G, Krantz I, Nordin P, Mtweve S, Ahlberg B, Mosha G, \u003cem\u003eet al.,\u003c/em\u003e (2005), \u0026lsquo; A six year follow-up of schoolchildren for urinary and intestinal schistosomiasis and soil- transmitted helminthiasis in Northern Tanzania\u0026rsquo; \u003cem\u003eActa Tropica\u003c/em\u003e, 93(2): 131-40.\u003c/li\u003e\n\u003cli\u003ePointer JP and Jourdane, (2000), \u0026lsquo;Biological control of the snail hosts of schistosomiasis in areas of low transmission: The example of the Caribbean area. \u003cem\u003eActa Tropica\u003c/em\u003e 77(1):53-60.\u003c/li\u003e\n\u003cli\u003eSacolo H, Chimbari M and Kalinda C, (2018), \u0026lsquo;Knowledge, attitudes and practices on schistosomiasis in Sub-Sahara Africa\u0026rsquo; \u003cem\u003eBMC Infectious Diseases\u003c/em\u003e 18(1): 46.doi:10.1186/s12879-017-2923-6.\u003c/li\u003e\n\u003cli\u003e\u0026nbsp;Sun L, Wang w, Hong Q-B, Li S-Z, Liang Y-S, Yang H-T \u003cem\u003eet al., \u003c/em\u003e(2017) \u0026lsquo;Approaches being used in the national schistosomiasis elimination programme in China\u0026rsquo; \u003cem\u003eInfectious \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; Diseases of\u0026nbsp; Poverty\u003c/em\u003e\u0026nbsp; 6:55 doi 10.1186/s40249-017-0271-9\u003cem\u003e.\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003eTing Lu X, GuQY, Limpanont Y, Song LG, Wu ZD, Okanurak K \u003cem\u003eet al., \u003c/em\u003e(2018) 'An update\u0026nbsp;on global epidemiological distribution, transmission interruption and control methods. \u003cem\u003eInfectious \u0026nbsp;\u0026nbsp; Diseases of Poverty\u003c/em\u003e7(1): 28.\u003c/li\u003e\n\u003cli\u003eWorld Health Organization,( 2018), \u0026lsquo;Schistosomiasis\u0026rsquo; www.who.int/schistosomiasis/disease/en/\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":"Schistosomiasis, Snail vector, Cercarial shedding, Kilimanjaro, Tanzania. ","lastPublishedDoi":"10.21203/rs.3.rs-5371989/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5371989/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e Schistosomiasis, a parasitic disease caused by blood flukes, is still a public health problem in low-income countries like Tanzania. Of the 201 million people infected with schistosomiasis globally, 91% are in sub-Sahara Africa countries. In Tanzania, Mass Drug Administration (MDA) is one of the key interventions to control schistosomiasis, but rapid re-infection after treatment lead to persistent high prevalence of schistosomiasis in key groups like school-aged children. Snail control is an alternative, however there is limited information on epidemiology and interventions on snails that that transmit schistosomiasis in Tanzania.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethodology: \u003c/strong\u003eA cross sectional study was conducted at Kileo ward in Mwanga District, from April-May 2019. The snails were collected manually using scooping technique and location where the snails were obtained was mapped by using Global Positioning System (GPS). Physico-chemical properties of water from each collection site were assessed using a multiparameter pH meter. The snails sampled at individual site were transferred to a laboratory for analysis within 4 hours of collection. The species and genus of snails were identified by shell morphology. Cercarial shedding was assessed over the first 48 hours after collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eA total of\u003cstrong\u003e \u003c/strong\u003e300 snails were collected from four different sites where people come into contact with water. The species of snails identified were \u003cem\u003eBulinus africanus \u003c/em\u003e(208) and \u003cem\u003eBulinus forskali \u003c/em\u003e(92). Snails of genus \u003cem\u003eBiomphalaria\u003c/em\u003e were not identified among the collected snails. No snail was found to shed cercaria of schistosomiasis after being exposed to light.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e Finding of \u003cem\u003eBulinus spp \u003c/em\u003esupport high occurrence of \u003cem\u003eSchistosoma haematobium\u003c/em\u003e and in the area and the need for planning of snail control activities in this setting. There is a need to sample snails over a long period, in different seasons of the year, to map if there is season variability of snail species especially for those transmitting \u003cem\u003eSchistosoma mansoni.\u003c/em\u003e\u003c/p\u003e","manuscriptTitle":"Distribution of Snails species and its infectivity with Schistosomes at Mwanga District, North Eastern Tanzania.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-04 13:47:11","doi":"10.21203/rs.3.rs-5371989/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":"2ddfabaf-1f41-428e-8619-0c060ebe9799","owner":[],"postedDate":"December 4th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-01T09:23:27+00:00","versionOfRecord":[],"versionCreatedAt":"2024-12-04 13:47:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5371989","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5371989","identity":"rs-5371989","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}