Molecular Characterization and Public Health Risk of Cryptosporidium Species in Livestock and Drinking Water Across Nigeria’s Six Geopolitical Zones

Cryptosporidium species are zoonotic protozoan parasites with significant diarrheal disease burden globally, and their species and subtype distribution in Nigerian livestock and water systems has not been comprehensively characterized. This study conducted the first nationwide molecular characterization of Cryptosporidium species in livestock and drinking water across Nigeria's six geopolitical zones and quantified the associated public health risk. Fecal samples were collected from 600 livestock comprising cattle, goats, and pigs from 36 farms distributed across all six zones. Drinking water samples were obtained from 180 sources including boreholes, rivers, and treated pipe water from 12 states. DNA extraction and PCR amplification of the SSU rRNA gene followed by sequencing enabled species identification. Subtyping of C. parvum isolates used gp60 gene sequencing. Public health risk was assessed using quantitative microbial risk assessment modelling incorporating water contamination levels, consumption rates, and dose-response data. Cryptosporidium was detected in 34.2% of livestock fecal samples. C. parvum subtype families IIa and IId were dominant in cattle, suggesting zoonotic transmission potential. Oocyst concentrations in surface water were significantly higher in zones where livestock-water access overlap was greatest. Annual infection risk through drinking water exceeded the 1 per 10,000 WHO benchmark in 41.7% of assessed water sources in the North West and North East zones. The study provides an original nationwide Cryptosporidium molecular and risk landscape for Nigeria, informing water safety policy and livestock management guidelines. Keywords: Cryptosporidium, molecular characterization, drinking water, Nigeria, zoonotic risk