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| Format: | Recurso digital |
| Language: | English |
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2024
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| Online Access: | https://doi.org/10.5281/zenodo.16778422 |
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| _version_ | 1866901893961220096 |
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| author | Knopp, Stefanie Trippler, Lydia |
| author_facet | Knopp, Stefanie Trippler, Lydia |
| contents | <p>This dataset is part of the publication: <strong><span lang="EN-US">Impact of chemical snail control on intermediate host snail populations for urogenital schistosomiasis elimination in Pemba, Tanzania: Findings of a 3-year intervention study</span></strong></p> <p><strong><span lang="EN-US">Background<span> </span></span></strong><span lang="EN-US">The World Health Organization (WHO) has set the goal to eliminate schistosomiasis as a public health problem globally by 2030 and to interrupt transmission in selected areas. Chemical snail control is one important measure to reduce transmission and achieve local elimination. </span><span lang="EN-US">We aimed to assess the impact of several rounds of chemical snail control on the presence and number of the <em>Schistosoma haematobium</em> intermediate snail host (<em>Bulinus </em>spp.) in water bodies (</span><span lang="EN-US">WBs) on Pemba Island, Tanzania, a setting targeted for elimination of urogenital schistosomiasis</span><span lang="EN-US">.</span></p> <p><strong><span lang="EN-US">Methods<span> </span></span></strong><span lang="EN-US">During the three annual intervention periods of the SchistoBreak study implemented in the north of Pemba from 2020 to 2024, malacological surveys were conducted up to four times per period in WBs of hotspot implementation units (IUs). Present freshwater snail species, vegetation, and WB characteristics were recorded. If <em>Bulinus</em> were found, the snails were inspected for <em>Schistosoma </em>infection and snail control with niclosamide was conducted.</span></p> <p><strong><span lang="EN-US">Results<span> </span></span></strong><span lang="EN-US">Across the three intervention periods, a total of 112 WBs were identified in 8 hotspots IUs. </span><span lang="EN-US">The spatial distribution of WBs with <em>Bulinus</em> per IU was heterogeneous, ranging from 0.0% (0/15) of WBs infested in one IU in 2022 to 80.0% (8/10) of WBs infested in one IU in 2021. <em>Bulinus</em> presence was significantly associated with lower pH values in WBs (odds ratio: 0.2, 95% confidence interval: 0.1-0.4). A total of 0.2% (6/2360) of collected <em>Bulinus</em> were shedding <em>Schistosoma </em>cercariae. Following snail control, the number of <em>Bulinus</em> decreased or remained absent in </span><span lang="EN-US">56.7% (38/67) of visits at WBs when compared to the previous visit in 2021, 54.9% (28/51) in 2022, and 33.3% (32/96) in 2023. In a total of 43.1% (22/55) of initially infested </span><span lang="EN-US">WBs, </span><span lang="EN-US">no <em>Bulinus</em> were found in the survey round conducted a few weeks after the first application of niclosamide. However, 25.4% (14/55) of </span><span lang="EN-US">WBs </span><span lang="EN-US">showed a </span><span lang="EN-US">pattern </span><span><span lang="EN-GB">of</span></span><span lang="EN-GB"> </span><span lang="EN-US">recurring</span><em><span lang="EN-US"> Bulinus</span></em><span lang="EN-US"> presence.</span></p> <p><strong><span lang="EN-US">Conclusions<span> </span></span></strong><span lang="EN-US">The distribution of WBs containing <em>Bulinus</em> was very heterogeneous. The percentage of <em>Bulinus</em> with patent <em>Schistosoma </em>infection in our study area was extremely low. Repeated niclosamide application reduced the number of <em>Bulinus</em> in WBs, but snails often recurred after one or multiple treatments. While chemical mollusciciding can reduce snail numbers, to fully break the <em>S. haematobium</em> transmission cycle, the timely diagnosis and treatment of infected humans, access to clean water, sanitation, and health education remain of prime importance.</span></p> <p> </p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_16778422 |
| institution | Zenodo |
| language | eng |
| publishDate | 2024 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Impact of chemical snail control on intermediate host snail populations for urogenital schistosomiasis elimination in Pemba, Tanzania: Findings of a 3-year intervention study Knopp, Stefanie Trippler, Lydia Bulinus/parasitology Control Elimination Molluscicide Niclosamide Schistosoma Snails Zanzibar <p>This dataset is part of the publication: <strong><span lang="EN-US">Impact of chemical snail control on intermediate host snail populations for urogenital schistosomiasis elimination in Pemba, Tanzania: Findings of a 3-year intervention study</span></strong></p> <p><strong><span lang="EN-US">Background<span> </span></span></strong><span lang="EN-US">The World Health Organization (WHO) has set the goal to eliminate schistosomiasis as a public health problem globally by 2030 and to interrupt transmission in selected areas. Chemical snail control is one important measure to reduce transmission and achieve local elimination. </span><span lang="EN-US">We aimed to assess the impact of several rounds of chemical snail control on the presence and number of the <em>Schistosoma haematobium</em> intermediate snail host (<em>Bulinus </em>spp.) in water bodies (</span><span lang="EN-US">WBs) on Pemba Island, Tanzania, a setting targeted for elimination of urogenital schistosomiasis</span><span lang="EN-US">.</span></p> <p><strong><span lang="EN-US">Methods<span> </span></span></strong><span lang="EN-US">During the three annual intervention periods of the SchistoBreak study implemented in the north of Pemba from 2020 to 2024, malacological surveys were conducted up to four times per period in WBs of hotspot implementation units (IUs). Present freshwater snail species, vegetation, and WB characteristics were recorded. If <em>Bulinus</em> were found, the snails were inspected for <em>Schistosoma </em>infection and snail control with niclosamide was conducted.</span></p> <p><strong><span lang="EN-US">Results<span> </span></span></strong><span lang="EN-US">Across the three intervention periods, a total of 112 WBs were identified in 8 hotspots IUs. </span><span lang="EN-US">The spatial distribution of WBs with <em>Bulinus</em> per IU was heterogeneous, ranging from 0.0% (0/15) of WBs infested in one IU in 2022 to 80.0% (8/10) of WBs infested in one IU in 2021. <em>Bulinus</em> presence was significantly associated with lower pH values in WBs (odds ratio: 0.2, 95% confidence interval: 0.1-0.4). A total of 0.2% (6/2360) of collected <em>Bulinus</em> were shedding <em>Schistosoma </em>cercariae. Following snail control, the number of <em>Bulinus</em> decreased or remained absent in </span><span lang="EN-US">56.7% (38/67) of visits at WBs when compared to the previous visit in 2021, 54.9% (28/51) in 2022, and 33.3% (32/96) in 2023. In a total of 43.1% (22/55) of initially infested </span><span lang="EN-US">WBs, </span><span lang="EN-US">no <em>Bulinus</em> were found in the survey round conducted a few weeks after the first application of niclosamide. However, 25.4% (14/55) of </span><span lang="EN-US">WBs </span><span lang="EN-US">showed a </span><span lang="EN-US">pattern </span><span><span lang="EN-GB">of</span></span><span lang="EN-GB"> </span><span lang="EN-US">recurring</span><em><span lang="EN-US"> Bulinus</span></em><span lang="EN-US"> presence.</span></p> <p><strong><span lang="EN-US">Conclusions<span> </span></span></strong><span lang="EN-US">The distribution of WBs containing <em>Bulinus</em> was very heterogeneous. The percentage of <em>Bulinus</em> with patent <em>Schistosoma </em>infection in our study area was extremely low. Repeated niclosamide application reduced the number of <em>Bulinus</em> in WBs, but snails often recurred after one or multiple treatments. While chemical mollusciciding can reduce snail numbers, to fully break the <em>S. haematobium</em> transmission cycle, the timely diagnosis and treatment of infected humans, access to clean water, sanitation, and health education remain of prime importance.</span></p> <p> </p> |
| title | Impact of chemical snail control on intermediate host snail populations for urogenital schistosomiasis elimination in Pemba, Tanzania: Findings of a 3-year intervention study |
| topic | Bulinus/parasitology Control Elimination Molluscicide Niclosamide Schistosoma Snails Zanzibar |
| url | https://doi.org/10.5281/zenodo.16778422 |