Genetic diversity of Cryptosporidium species in Njoro Sub County, Nakuru, Kenya.

Cryptosporidium spp. cause cryptosporidiosis in humans through zoonotic and anthroponotic transmission. Previous studies illustrated the significance of domestic animals as reservoirs of this parasite. Cryptosporidium occurs in Njoro River; a main source of water to humans and animals. However, there is no information on the Cryptosporidium spp. and genotypes circulating in Njoro Sub County. A total of 2174 samples from humans, cattle, chickens, sheep and goats were assessed for the presence of Cryptosporidium spp. Thirty-three positive samples were subsequently successfully sequenced and compared to Cryptosporidium sequences in the GenBank repository using NCBI's (National Center for Biotechnology Information) online BLAST (Basic Local Alignment Search Tool) algorithmic program. Sequence alignment was done using the Clustal W program and phylogenetic analysis was executed in MEGA X (Molecular Evolutionary Genetics Analysis version X). The prevalence of cryptosporidiosis in Njoro Sub County is 6.99%. Cryptosporidium spp. present in the watershed showed great genetic diversity and nine Cryptosporidium species were recorded: Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium ubiquitum, Cryptosporidium meleagridis, Cryptosporidium andersoni, Cryptosporidium baileyi, Cryptosporidium muris, Cryptosporidium xiaoi and Cryptosporidium viatorum. This is the first study to report the presence of C. viatorum in Kenya. Cattle is the major reservoir of zoonotic Cryptosporidium spp. while goats harbored the lowest number of species. Humans and domestic animals drink the contaminated water from Njoro River, humans are therefore, exposed to a high cryptosporidiosis risk. © Indian Society for Parasitology 2021.