Bunyavirus and Paramyxovirus infections at the interface between wildlife, livestock and humans in Nigeria and Cameroon

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In Nigeria and Cameroon, there are overlapping areas of wildlife and livestock animals and humans, which poses an increased transmission risk for zoonotic pathogens. These include urban areas with livestock markets and backyard holdings and urban breeding and resting-grounds of fruit bats, which are hunted and sold as bushmeat. These risks are increased by poor municipal infrastructures and the lack of hygienic knowledge among the population. Therefore the potential reservoir functions of fruit bats, rodents, rats, shrews, frogs, toads and lizards for zoonotic bunya- and paramyxoviruses in general, and for Rift Valley fever virus (RVFV) and Henipa-like viruses (HNLV) in particular will be assessed. In a first step, using a One Health approach, seroprevalence rates will be determined in small ruminants (RVFV) and pigs (HNLV) to reveal potential hot spots for arboviral and bat-associated infections. Data for the RVFV incidence in Cameroon are already available, while the RVFV situation in Nigeria and the presence of HNLV infections will have to be determined. In potentially high infection risk areas samples from the above species will be collected and tested to reveal persistent or overcome bunya- and paramyxoviruses infections using molecular diagnostics and serological methods. In addition, samples from humans with contacts to these potential reservoir species (as determined by a questionnaire) will be examined using the same molecular diagnostic and serological methods. In a second part of the proposed project cell lines derived from the above potential reservoir hosts will be infected in vitro with RVFV isolates and by using HNLV transcription and replication competent virus like particles (trVLPs) to obtain evidence for a susceptibility of these species. Cell lines from bat (Rousettus aegyptiacus, Eptesicus serotinus) and various rodent and other species (e.g. Myodes glareolus, Apodemus agrarius, Rattus norvegicus) are available at the Friedrich-Loeffler-Institut (FLI) and more fruit bat and rodent cell lines can be supplied by cooperation partners (Prof. Drosten , Bonn, Dr. Essbauer, Munich). In vivo challenge studies of fruit bats (Rousettus aegyptiacus), rats (Rattus rattus) and voles as well as frogs (Xenopus laevis) with RVFV will be carried out to determine the susceptibility, pathogenesis, the course of infection and virus shedding of these species. This work will be carried out in close collaboration between the FLI and seven African partners (including five universities) which includes training of five African and two German PhD/doctoral students using integrated curricula, annual workshops on project-related issues in partner countries and two 6-month long research visits of African PhD students at the FLI. Progress will steadily be monitored internally by a Steering group to ensure also the constant flow of information and assay data, and distribution of protocols and of samples/reagents.