Distribution of Snails in Associated Vegetations and Schistosome Infection Prevalence Along the Shores of Lake Victoria in Mbita, Kenya: A Cross-Sectional Study.

BACKGROUND

Schistosomiasis due to remains a major public health problem and cause of morbidity and mortality in sub-Saharan Africa despite the implementation of control programmes. More than 6 million Kenyans are at risk of infection. Regarding control measures, snail species, which are the obligatory intermediate hosts for transmission of have been neglected. Mbita subcounty in Homa Bay County, western Kenya, along Lake Victoria basin, has a high prevalence of infection despite mass drug administration. This study aimed to determine the abundance of with their associated vegetation and schistosome infection rates, along Mbita shoreline.

METHODS

Sixteen purposively selected sites along the Mbita shoreline were sampled for snails using a 30-minute scooping technique. Global positioning system technology was used to map selected sites. The associated vegetation at sampling sites were collected and identified. Schistosome infection status among the snails was determined via the detection of cercaria shedding.

RESULTS

A total of 3,135 snails were collected. The number of snails collected differed significantly between the 16 sites (F=11.735; degrees of freedom [df]=15.836; <.001). Significant mean differences (MD) were also observed in terms of the number of snails collected per vegetation type (F=7.899; df=5.846; <.001). The mean number of snails collected from was significantly higher than that from (MD= 2.03; <.001), (MD=4.15; <.010), and mixed with (MD=2.516; <.010). A total of 21 (0.67%) snails shed human cercariae, while 27 (0.86%) snails shed nonhuman cercariae, despite 14 sites having human faeces contamination.

CONCLUSION

Although the schistosome infection prevalence among the snails was low, these sites may still be important exposure sites. is the main vegetation type associated with a high abundance of snails. Molecular techniques are necessary for verification of schistosome positivity among the snails.