Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania
Urogenital schistosomiasis is a neglected tropical disease of significant public health concern caused by the trematode species Schistosoma haematobium. Its transmission is localised and heterogeneous, with seasonal occurrences in Tanzania primarily facilitated by Bulinus spp. snails, which serve as...
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Elsevier
2025-01-01
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| Series: | Current Research in Parasitology and Vector-Borne Diseases |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2667114X25000081 |
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| author | Nyanda C. Justine Humphrey D. Mazigo Antje Fuss Bonnie L. Webster Eveline T. Konje Klaus Brehm Andreas Mueller |
| author_facet | Nyanda C. Justine Humphrey D. Mazigo Antje Fuss Bonnie L. Webster Eveline T. Konje Klaus Brehm Andreas Mueller |
| author_sort | Nyanda C. Justine |
| collection | DOAJ |
| description | Urogenital schistosomiasis is a neglected tropical disease of significant public health concern caused by the trematode species Schistosoma haematobium. Its transmission is localised and heterogeneous, with seasonal occurrences in Tanzania primarily facilitated by Bulinus spp. snails, which serve as intermediate hosts. To plan effective, data-driven control measures, it is crucial to understand the epidemiology of schistosomes in these snails. This study aimed to investigate the seasonal distribution, abundance, and Schistosoma spp. infections (assessed via cercarial emergence) in Bulinus spp. snails in two districts, Maswa and Meatu, in the Simiyu Region of Tanzania. Malacological surveys were conducted at 90 sites in total, comprising sites in 35 rivers, 32 ponds, and 23 branching streams. Each study site was sampled once during the rainy season and once during the dry season. Snails were collected using a standard scoop- and handpicking technique by two people for 15 min at each site. The collected snails were morphologically identified and subjected to a cercarial emergence experiment. Water physicochemical characteristics were recorded simultaneously with snail collection using a portable multiparameter water meter. The data were analysed using STATA v. 17. A total of 4997 Bulinus spp. snails were collected from 90 sites in the two districts. Of these, 91.4% (95% CI: 90.5–92.1%) were morphologically identified as Bulinus nasutus and 8.6% (95% CI: 7.8–9.4%) were identified as Bulinus globosus. Bulinus spp. snail abundance was almost evenly distributed across seasons, with 50.4% (95% CI: 48.9–51.7%) collected during the dry season and 49.6% (95% CI: 48.2–51.0%) collected during the rainy season. Water temperature and salinity were significantly negatively correlated with snail abundance (both P < 0.001). Schistosoma spp. cercarial emergence followed a seasonal pattern and was significantly higher during the rainy season (P = 0.005). Our findings underscore that B. nasutus was the most abundant freshwater snail distributed at nearly all the study sites during the rainy and dry seasons. Therefore, appropriate snail control strategies are recommended to complement ongoing schistosomiasis control strategies in the Simiyu Region. |
| format | Article |
| id | doaj-art-35e0e01e43434650888110be70f2e64c |
| institution | Kabale University |
| issn | 2667-114X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Elsevier |
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| series | Current Research in Parasitology and Vector-Borne Diseases |
| spelling | doaj-art-35e0e01e43434650888110be70f2e64c2025-02-06T05:13:00ZengElsevierCurrent Research in Parasitology and Vector-Borne Diseases2667-114X2025-01-017100248Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern TanzaniaNyanda C. Justine0Humphrey D. Mazigo1Antje Fuss2Bonnie L. Webster3Eveline T. Konje4Klaus Brehm5Andreas Mueller6Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania; Corresponding author.Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, TanzaniaMedmissio – Institute for Global Health, Würzburg & Department of Tropical Medicine, Klinikum Würzburg Mitte gGmbH, Würzburg, GermanyDepartment of Science, The Natural History Museum, London, United KingdomDepartment of Epidemiology and Biostatistics, School of Public Health, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, TanzaniaInstitute of Hygiene and Microbiology, University of Würzburg, Josef-Schneider-Strasse 2, D-97080, Würzburg, GermanyMedmissio – Institute for Global Health, Würzburg & Department of Tropical Medicine, Klinikum Würzburg Mitte gGmbH, Würzburg, GermanyUrogenital schistosomiasis is a neglected tropical disease of significant public health concern caused by the trematode species Schistosoma haematobium. Its transmission is localised and heterogeneous, with seasonal occurrences in Tanzania primarily facilitated by Bulinus spp. snails, which serve as intermediate hosts. To plan effective, data-driven control measures, it is crucial to understand the epidemiology of schistosomes in these snails. This study aimed to investigate the seasonal distribution, abundance, and Schistosoma spp. infections (assessed via cercarial emergence) in Bulinus spp. snails in two districts, Maswa and Meatu, in the Simiyu Region of Tanzania. Malacological surveys were conducted at 90 sites in total, comprising sites in 35 rivers, 32 ponds, and 23 branching streams. Each study site was sampled once during the rainy season and once during the dry season. Snails were collected using a standard scoop- and handpicking technique by two people for 15 min at each site. The collected snails were morphologically identified and subjected to a cercarial emergence experiment. Water physicochemical characteristics were recorded simultaneously with snail collection using a portable multiparameter water meter. The data were analysed using STATA v. 17. A total of 4997 Bulinus spp. snails were collected from 90 sites in the two districts. Of these, 91.4% (95% CI: 90.5–92.1%) were morphologically identified as Bulinus nasutus and 8.6% (95% CI: 7.8–9.4%) were identified as Bulinus globosus. Bulinus spp. snail abundance was almost evenly distributed across seasons, with 50.4% (95% CI: 48.9–51.7%) collected during the dry season and 49.6% (95% CI: 48.2–51.0%) collected during the rainy season. Water temperature and salinity were significantly negatively correlated with snail abundance (both P < 0.001). Schistosoma spp. cercarial emergence followed a seasonal pattern and was significantly higher during the rainy season (P = 0.005). Our findings underscore that B. nasutus was the most abundant freshwater snail distributed at nearly all the study sites during the rainy and dry seasons. Therefore, appropriate snail control strategies are recommended to complement ongoing schistosomiasis control strategies in the Simiyu Region.http://www.sciencedirect.com/science/article/pii/S2667114X25000081Urogenital schistosomiasisBulinus spp. snailsSchistosoma haematobiumSeasonal distributionCercarial sheddingSimiyu |
| spellingShingle | Nyanda C. Justine Humphrey D. Mazigo Antje Fuss Bonnie L. Webster Eveline T. Konje Klaus Brehm Andreas Mueller Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania Current Research in Parasitology and Vector-Borne Diseases Urogenital schistosomiasis Bulinus spp. snails Schistosoma haematobium Seasonal distribution Cercarial shedding Simiyu |
| title | Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania |
| title_full | Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania |
| title_fullStr | Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania |
| title_full_unstemmed | Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania |
| title_short | Seasonal distribution and cercarial shedding of Bulinus spp. snails: Implications for urogenital schistosomiasis control in the Simiyu Region, northwestern Tanzania |
| title_sort | seasonal distribution and cercarial shedding of bulinus spp snails implications for urogenital schistosomiasis control in the simiyu region northwestern tanzania |
| topic | Urogenital schistosomiasis Bulinus spp. snails Schistosoma haematobium Seasonal distribution Cercarial shedding Simiyu |
| url | http://www.sciencedirect.com/science/article/pii/S2667114X25000081 |
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