Molecular Identification of Schistosoma Species Associated with Atypical Urinary Eggs in Abuja (Nigeria): Evidence of Potential Zoonotic Transmission

Abstract

Schistosomiasis remains a major public health concern in Nigeria. We molecularly characterized Schistosoma eggs obtained from human urine to identify species and assess the presence of hybrid schistosomes in Abuja, Nigeria. Urine samples were collected from 1887 participants aged five years and above. Samples were examined for Schistosoma eggs using light microscopy. A total of 507 (26.9%) were positive for any form of Schistosoma while 91 (4.8%) had atypical Schistosoma eggs. DNA extracted from pooled ova was analyzed using metagenomic sequencing, read mapping, phylogenetic analysis, and BLASTn confirmation. Molecular analyses identified genetic signatures associated with both S. haematobium and S. bovis within pooled human urine samples, indicating the co-circulation of multiple schistosome species in the study area. Phylogenetic analyses based on trans-ITS and mitochondrial COX1 markers supported the presence of distinct nuclear and mitochondrial schistosome lineages. However, because sequencing was performed on pooled egg samples, the findings cannot distinguish between true recombinants and mixed infections involving co-circulating parental species. These findings highlight the potential complexity of schistosome transmission dynamics in endemic communities and underscore the need for enhanced molecular surveillance, especially single-parasite genomic approaches, and integrated One Health investigations to better understand schistosome transmission and its implications for control and elimination efforts in Nigeria.