One health; Parasitology; Social-ecological systems; Geographical information system; Phylogeography; Cattle; Epidemiology; Risk profiling; Schistosoma spp.; Land use; Transdisciplinarity; Human; Hydrology; Population genetics; Fasciola spp.
Kouadio Jules N., Giovanoli Evack Jennifer, Achi Louise Y., Fritsche Dominik, Ouattara Mamadou, Silué Kigbafori D., Bonfoh Bassirou, Hattendorf Jan, Utzinger Jürg, Zinsstag Jakob, Balmer Oliver, N’Goran Eliézer K. (2020), Prevalence and distribution of livestock schistosomiasis and fascioliasis in Côte d’Ivoire: results from a cross-sectional survey, in BMC Veterinary Research
, 16(1), 446-446.
Giovanoli Evack Jennifer, Kouadio Jules N., Achi Louise, Balmer Oliver, Hattendorf Jan, Bonfoh Bassirou, Zinsstag Jakob, N’Goran Eliézer K., Utzinger Jürg (2020), Accuracy of the sedimentation and filtration methods for the diagnosis of schistosomiasis in cattle, in Parasitology Research
, 119(5), 1707-1712.
Giovanoli Evack Jennifer, Schmidt Remo S., Boltryk Sylwia D., Voss Till S., Batil Annour A., Ngandolo Bongo N., Greter Helena, Utzinger Jürg, Zinsstag Jakob, Balmer Oliver (2020), Molecular Confirmation of a Fasciola Gigantica × Fasciola Hepatica Hybrid in a Chadian Bovine, in Journal of Parasitology
, 106(2), 316-316.
Angora Etienne K., Allienne Jean-François, Rey Olivier, Menan Hervé, Touré André O., Coulibaly Jean T., Raso Giovanna, Yavo William, N'Goran Eliézer K., Utzinger Jürg, Balmer Oliver, Boissier Jérôme (2020), High prevalence of Schistosoma haematobium × Schistosoma bovis hybrids in schoolchildren in Côte d'Ivoire, in Parasitology
, 147(3), 287-294.
Angora Etienne K., Boissier Jérôme, Menan Hervé, Rey Olivier, Tuo Karim, Touré Andre O., Coulibaly Jean T., Méité Aboulaye, Raso Giovanna, N’Goran Eliézer K., Utzinger Jürg, Balmer Oliver (2019), Prevalence and Risk Factors for Schistosomiasis among Schoolchildren in two Settings of Côte d’Ivoire, in Tropical Medicine and Infectious Disease
, 4(3), 110-110.
Schistosoma and Fasciola species are trematode parasites that are of considerable public health importance and cause significant livestock disease and economic losses. In a recently completed project funded by the Swiss National Science Foundation, we demonstrated the presence of Schistosoma haematobium in humans and Schistosoma bovis and Fasciola gigantica in different livestock species in Côte d’Ivoire and Chad. We further showed that infection patterns in humans and livestock are intimately linked, and governed by ethnicity and life-styles. However, species distinction using standard diagnostic methods is unreliable, so there is still uncertainty about the exact species present. The co-location of multiple human and animal trematodes in the same geographical areas suggests the possibility of hybrid species. Indeed, this phenomenon has been observed for both Schistosoma and Fasciola; yet, it remains to be investigated for Côte d’Ivoire and Chad. Hybridization has been demonstrated to modify parasite characteristics including host ranges. Hybridization may thus alter transmission dynamics and challenges the validity and efficiency of existing diagnostic approaches and control strategies. The appearance of hybrids between human and animal-infective species in both Schistosoma and Fasciola, as well as their largely overlapping ecologies, call for investigating these two genera and the diseases they cause together using a One Health approach.The goal of this project is to gain a deeper understanding of trematode transmission dynamics and the role of hybrids in sub-Saharan Africa. We address this goal by pursuing five research questions. First, which Schistosoma and Fasciola species are present in Côte d’Ivoire? Second, what is the frequency of different hybrids and does their distribution or other parameters differ from those of the parent species? Third, how are the parasite populations differentiated or linked between different host species (humans, cattle, sheep, goats and snails) and are there host-specific genotypes? Fourth, how does transhumance (i.e. the annual cross-border migration of mobile pastoralists with their herds from Mali) affect parasite dynamics and hybridization in Côte d’Ivoire? Fifth, how strong is re-infection pressure after treatment of cattle with triclabendazole, the current treatment of choice against Fasciola infection?We will generate complete mitochondrial genomes and partial whole-genome sequences of multiple local genotypes to optimize the available molecular methods for West African trematode genotypes. We will employ molecular methods to identify species and hybrids. Population genetic analyses of circulating genotypes in each host species will complement epidemiological studies. Schistosoma bovis will be investigated in greater detail because its hybridization appears to be common and thus may generate human-infective parasites with a livestock reservoir. Cohorts of Fasciola-infected cattle will be treated with triclabendazole and their reinfection status followed over time to investigate infection pressures. Finally, data from the current and the preceding project will contribute to a deterministic model of trematode transmission.The proposed research will quantify trematode diversity and transmission and clarify whether transhumance affects local trematode population dynamics indicating zones of increased risk for emergence of new parasites and zoonotic disease. The results will elucidate to what extent hybridization changes parasite host ranges and transmission, and the validity of current diagnosis and control approaches. The model of trematode transmission will allow us to investigate the effectiveness of competing control strategies for reducing human disease burden and improving livestock production. The locally adapted molecular methods and the training of African students and technicians will contribute to capacity building in partner institutions in sub-Saharan Africa.