Spatiotemporal and seasonal transmission dynamics of and snail infectivity in Ase River catchment, Delta State, Nigeria.

are intermediate snail hosts of . Despite their vectorial role, the transmission dynamics and infectivity of these intermediate snail hosts remain understudied in the Ase River. This longitudinal study evaluated the geospatial and seasonal transmission patterns and infectivity of three vectors between November 2020 and October 2022 in the Ase River catchment, Delta State, Nigeria. Eleven (11) geospatial water contact coordinates were mapped for monthly spatiotemporal collection of species along the Ase River and its catchment, for two years. Snail sampling was performed for 45 min at each study site using scooping/hand-picking techniques and subsequently counted, identified and recorded. Snails of the genus were individually placed in a beaker containing distilled water and exposed to light to shed cercariae which were identified to be human schistosome type. The number of infected snails for each month and season was also documented to analyze the spatiotemporal and seasonal transmission dynamics of infectivity. Out of the 2345 snails collected, a total of 41.45% were found to be infected with . The monthly infectivity of snails varied significantly ( < 0.05) throughout the study period ( =  < 0.0001; F = 23.11; df = 11). Further analysis showed a strong significant association (χ = 23.57; df = 11;  = 0.015) between the study years. The Principal Component Analysis (PCA) results suggest that infectivity within the Ase River catchment area was primarily associated with the months of February and January. consistently had the highest transmission potential, followed by and . ANOVA confirms that the monthly/study site infectivity and transmission potential in , and were statistically, significant ( < 0.05). These results demonstrated a clear distinction in the patterns and relationships between the different months in terms of snail infectivity and seasonal transmission potential. This understanding will help in the continuous monitoring and targeted interventions to control schistosomiasis transmission in Ase River.