E Leger4; S Catalano4; A M Borlase4; C B Fall5; S D Diop1; L Yasenev4; B Webster3; A M Emery3; D Rollinson3; K Bâ2; N D Diouf6; M Sene6; J P Webster4;
1 IFSAR - Université de Thiès, Bambey, Senegal; 2 Institut de Recherche pour le Développement, Senegal; 3 Natural History Museum, UK; 4 Royal Veterinary College, University of London, UK; 5 Universite Cheikh Anta Diop de Dakar, Senegal; 6 Universite Gaston Berger de Saint Louis, Senegal
DiscussionSchistosomiasis is a neglected tropical disease caused by Schistosoma parasitic worms, which inflicts a significant burden on human and animal populations, particularly across sub-Saharan Africa. Anthropogenic land-use changes affect the distribution and availability of suitable definitive and intermediate hosts, increasing opportunities for hybridization between human and animal schistosomes with subsequent zoonotic transmission. This can have a substantial impact on the dynamics and distribution of schistosomiasis, with further challenges and constraints for effective control. Our aim was to elucidate the role of different definitive hosts as reservoirs of zoonotic Schistosoma single species and hybrids in a region of northern Senegal subject to important anthropogenic change. Extensive and systematic parasite sampling from human, livestock, and rodent definitive hosts, combined with snail intermediate hosts, were performed over three years across key transmission sites in northern Senegal. Multi-locus molecular analyses of all Schistosoma isolates, followed by Maximum Likelihood (ML) and Bayesian Inference (BI), were used to infer phylogenetic and transmission dynamics between the circulating zoonotic Schistosoma species/hybrids and their hosts. Molecular analyses confirmed the presence of widespread viable hybridization within and between Schistosoma species of humans and animals. Phylogenetic analyses indicated shared transmission of zoonotic Schistosoma species and hybrids between humans and animals (both wild and domestic), providing unique insights into the role of different host species in maintaining transmission. Our study emphasizes the need for a One Health multi-host framework for schistosomiasis control in both people and animals living in high zoonotic transmission zones of sub-Saharan Africa.