Genetic Profile of Schistosomes from Malian hotspot Areas with Urogenital Schistosomiasis

Abstract

Background - Although schistosomiasis is a public health issue in Mali, little is known about the genetic profile. The purpose of this study was to analyze the genetic profile of the schistosomes of Schistosoma haematobium group in school aged children in various sites of Mali. Methods - Urine samples were collected from 07 to 21 November 2021 and subjected to a filtration method for the presence S. haematobium eggs. The study took place in two schistosomiasis endemic villages, qualified as hotspots according to the World Health Organization (WHO) definition Fangouné Bamanan and Diakalel in Kayes’ region. Molecular biology (Cox1 and ITS2/18S) was used as eggs taxonomic parameters. Results - A total of 789 miracidium were collected individually from 63 school aged children and stored on Whatman Find The Agent (FTA) cards for molecular analysis. After genotyping for species and hybrid identification using rapid diagnostic multiplex mitochondrial Cox1 Polymerase chain reaction (PCR) and Amplification-refractory mutation system -ARMS_PCR analysis of the nuclear Internal Transcribed spacer - ITS2 and 18S regions, 338 (42.8%) and 45) (57.2%) of miracidium revealed S. bovis and S. haematobium profiles for Cox1, respectively; 749 (94.9%) and 40 (5.1%) revealed S. haematobium and S. haematobium/S. curassoni profiles for ITS/18S genes, respectively. There was a significant difference in the Cox1 and ITS2/18S profiles distribution between the two villages (p<0.0001). Overall, there was 360 (45.6%) cases of hybrids of which 322 (72.0%) were from Fangouné Bamanan. Three hybrids profiles [(Sb_ShxSc) with 2.3%); (Sb_ShxSh with 40,9%) ; (Sh_ShxSc with 2.8%) and one pure profile [Sh_ShxSh with 54.5%) were identified. The hybrid Sb_ShxSh appeared to be more frequent in Fangouné Bamanan (68%) whereas Sh_Sh/Sc was lightly represented in Diakalel (5.8%). Conclusions - Our findings show for the first time the presence of introgressive hybridization between S. haematobium and S. bovis/S. curassoni in humans at a large scale. More studies are needed on population genetics of schistosomes at the human and animal interface to evaluate the parasite’s gene flow and its consequences on epidemiology of the disease as well as the transmission to humans.