African zoonotic schistosomiasis: a paradigm shift

In Asia, Schistosoma japonicum infects humans and many animal species, making it a zoonotic disease. In Africa, the two major species infecting humans are Schistosoma mansoni and Schistosoma haematobium, which cause mesenteric and urogenital schistosomiasis, respectively. Despite the significance of these parasitic infections for human health, few studies have examined the zoonotic aspects of these parasites. In the initial section of this article, we examine the advancements made in analysing the zoonotic characteristics of S. japonicum, with a particular emphasis on the diverse scenarios observed in the field. We also review the role of rodents and non-human primates in transmitting S. mansoni and the emerging importance of cattle and rodents in hybrid schistosomiasis involving S. haematobium and Schistosoma bovis (a livestock and rodent parasite). Second, we examine the genetic diversity of these hybrid forms across their distribution in West Africa. Hybrid forms exhibit considerable diversity across all spatial levels, ranging from the transmission site to the national scale. Ultimately, we aim to explore the implications of zoonotic urogenital schistosomiasis in relation to the role of each host in its transmission, together with parasite gene flow, parasite diversity and parasite virulence. This article is part of the Royal Society Science+ meeting issue 'Parasite evolution and impact in action: exploring the importance and control of hybrid schistosomes in Africa and beyond'.