Molecular epidemiology of urinary schistosomiasis and characterization of Human and Animal infective schistosome species in endemic areas, Ogun State, Nigeria

Introduction: Schistosomiasis is a neglected tropical disease that affects humans and animals in tropical and subtropical regions worldwide.In Nigeria, infection with S. haematobium is the most prevalent and often times sympatric with the other species in the S.haematobium group which comprises of nine species; S. bovis, S. curassoni, S. guineensis, S. kisumuensis, S. leiperi, S. margrebowiei S. mattheei (species affecting livestock), S. haematobium, and S. intercalatum (species affecting human) all of which are morphologically identical and develop in the same freshwater pulmonates of the genera Bulinus.As a result of the similarities in their morphology, intermediate host, coupled with the occurrence of hybrids amongst the group, examining the cercariae or infected snails as well as clinical samples for the estimation of transmission of S. haematobium is always confounded with other species.Over the years, identification of cercariae, snails and human infected with S. haematobium) was carried out by using primers designed from a repeated sequence, DraI, in a PCR assay.Methods: This study was evaluated the incidence of infection of human and animal infective schistosome in snail and human population from 9 communities in 3 local Government areas in Ogun State, using a pair of new primers, ShND-1/ShND-2, to amplify the target sequence of 1117 bp.A total of 701 participants were included in this study and 214 snails were collected.Results: The overall prevalence of infection was 243 (35.5%) in human and 63 (29.5%) in snail samples using DRAI gene.Using the SHND1/2 only a few samples (0.71%) gave the expected base pair size for S.haematobium while majority showed bands of various base pair size indicating the likelihood of coinfection/hybridization between S.haematobium and its related species.Discussion: Prevalence mapping showed that Obafemi-Owode had the highest prevalence (53.7%), while Remo-North had the least prevalence (6.8%).Snail identification using PCR-RFLP of their entire ITS region including the 5.8S ribosomal RNA (rRNA) gene of infected snails showed that three Bulinus species, namely B. globosus, B. forskalii and B. camerunensis were identified. Conclusion:The PCR assay was sensitive and was able to differentiate S. haematobium from its related species; however sequencing has to be done to confirm these speculations.The findings are discussed in the presentation