Spatiotemporal and Seasonal Transmission Dynamics of Schistosoma haematobium and Snail Infectivity in Ase River Catchment, Southern Nigeria

Abstract

AbstractBulinusare intermediate snail hosts ofSchistosoma haematobium. 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 threeS. haematobiumvectors 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 ofBulinusspecies along the Ase River and its catchment, for two years. Snail sampling was performed for 45 minutes at each study site using scooping/hand-picking techniques and subsequently counted, identified, and recorded. Snails of theBulinusgenus 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 the season was also counted and recorded to establish spatiotemporal and seasonal infectivity transmission dynamics and infectivity. A total of 41.45% of the 2345Bulinussnails collected were infected withS. haematobium. The monthly infectivity ofBulinussnails varied significantly (P < 0.05) throughout the study period (P = < 0.0001; F = 23.11; df = 11). Further analysis showed a strong significant association (χ2 = 23.57; df = 11; p = 0.015) between the study years. The Principal Component Analysis (PCA) also indicates thatBulinusinfectivity in the Ase River catchment was primarily driven by February and January.B. truncatusconsistently had the highest transmission potential, followed byB. globosusandB. senegalensis. ANOVA confirms that the monthly/study site infectivity and transmission potential inB. truncates,B. globosusandS. senegalensiswere statistically, significant (P < 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.