Molecular Detection and Genotyping of Cryptosporidium Species in HIV-Positive Children in Anambra State, South East Nigeria

Cryptosporidiosis caused by Cryptosporidium species is a leading opportunistic parasitic infection in HIV-positive children, producing chronic life-threatening diarrhoea, and accurate species and genotype identification is critical for understanding transmission sources and infection severity. This study performs molecular detection and genotyping of Cryptosporidium species in HIV-positive children in Anambra State, South East Nigeria. An analytical cross-sectional design was employed, recruiting 200 HIV-positive children aged 6 months to 12 years from the paediatric ART clinic of Nnamdi Azikiwe University Teaching Hospital, Nnewi, and a general hospital in Onitsha. Stool samples were examined by modified Ziehl-Neelsen staining for oocysts, and positive and negative samples were subjected to DNA extraction and nested PCR amplification of the 18S rRNA gene. PCR products were sequenced, and BLAST analysis classified isolates to species and genotype level. Host risk factors including CD4 percentage, ART adherence, water source, and animal contact were correlated with infection status. Recent molecular studies from 2020 to 2024 document the predominance of C. hominis and C. parvum in Nigerian HIV-positive children, with C. hominis subtype IbA10G2 associated with severe diarrhoeal outcomes. This study generates the first Anambra-specific molecular dataset, filling a regional gap in Cryptosporidium genotyping research in HIV-positive Nigerian children. Keywords: Cryptosporidium, molecular genotyping, HIV-positive children, Anambra State, diarrhoea.