Identification of virus transmission networks to control key arboviral diseases in Kenya

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The recent unprecedent epidemics caused by chikungunya virus, Zika virus and dengue virus have exemplified that infections caused by arthropod-borne viruses (arboviruses) are a major global health problem. While arboviroses often originate in Sub-Saharan Africa, there is little knowledge on the spectrum of causative viruses, their prevalence, and their social impact in these regions. There is an urgent need to better understand the ecology of arbovirus transmission and maintenance, in order to develop control measures that limit key arboviral diseases in the seeding regions and worldwide. The major goal of this collaborative project is a holistic understanding of key arboviral diseases in Kenya, including sources of outbreaks, infection-related impacts on humans, as well as societal conditions and consequences of arbovirus incidence. A strong focus in all stages of research is on training and capacity building for future independent research in an African academic environment.During the first funding period we detected four previously unknown phleboviruses in sandflies in Baringo County, Kenya. Phylogenetic analyses based on complete genome sequences showed that one virus, named Ntepes virus, is related to viruses of the Karimabad serocomplex, whereas the other three viruses established a novel highly diverged clade in sister relationship to the sandfly fever Sicilian serocomplex, which is associated with febrile illness in humans. We could show that infection of new-born mice with Ntepes virus caused fatal illness and we detected neutralizing antibodies against this virus in human serum samples. Sandfly-borne phleboviruses have so far not been detected in Kenya. While the 1st funding period gave us a broader understanding of abundance patterns of several arboviruses in vectors, peri-domestic rodents, livestock and humans, the 2nd funding period will focus on amplification and transmission dynamics of key arboviruses identified in the 1st period. Furthermore, we gained insight into the awareness, incidence and economic impact of arboviral diseases during the 1st funding period. We will now use this knowledge to test suited intervention strategies to develop sustainable community-based vector control strategies. The key objectives are:(i) to study transmission dynamics in vectors and hosts for selected key arboviruses,(ii) to assess the impact of arboviral infections on human health and local society,(iii) to assess the effect of education and health information on behavioural change towards acceptance of well-targeted sustainable vector control intervention strategies in different socio-economic settings,(iv) to provide education, training, and capacity building in the fields of disease ecology, virology, and social sciences.Overall, the project aims to reduce arbovirus disease outbreaks locally and also globally by preventing geographic spread from seeding regions.