Revealing environmental drivers influencing the abundance of the Rift Valley fever virus vector Culex mosquito

Rift Valley fever is a neglected mosquito-borne viral disease caused by the Rift Valley fever virus (RVFV). Rift Valley fever outbreaks result in illness in humans, as well as in high mortality and abortion rates among domestic animals, hence subsequently impacting humans' livelihoods leading to severe socio-economic losses and increased poverty, especially in already vulnerable communities. Rift Valley fever presence is affected by the presence of it's mosquito vectors, however the drivers of mosquito vector presence and abundance are complex. Environmental factors such as climate, soil properties and the anthropogenic influence on land use have been identified as varying drivers of the population dynamics of RVF vectors such as the Culex spp, subsequently impacting the disease spread and outbreaks. To decrease RVF epidemics and therefore reduce the burden of disease for human and animals lives and livelihoods further understanding of the complex environmental balance of Culex spp mosquito populations is necessary. In my proposed scientific exchange with Dr. Melinda Rostal and Dr. Whitney Bagge from EcoHealth Alliance, over three months, I aim to build on my previous experiences gained through my research on Rift Valley fever in Chad (manuscript currently in preparation) during my PhD and to investigate the relationship between environmental factors and the population dynamics and abundance of RVF-relevant mosquito species from the Culex genus in South Africa. Precisely, with the proposed scientific exchange my four main aims are; 1) to reveal environmental drivers of the RVF vector Culex genus mosquito population abundance, 2) to enhance my analytical and critical thinking skills in the interface of human, animal and environmental health, 3) to increase my credibility and visibility within the scientific community by co-authoring on a peer-reviewed international publications resulting from the proposed scientific exchange, and finally 4) to connect and collaborate with the international network of One Health researchers at the EHA and their partners. I will work on already collected data encompassing 30 distinguishing environmental factors on soil properties (mineral densities, humidity), vegetation, climate and weather (precipitation, wind direction and speed), as well as data on Culex abundance. Overall as first step I will conduct a literature review to reveal the most frequently investigated environmental factors for explaining Culex spp abundance thus far. Herewith I will gain a profound overview of already existing investigated associations between environmental factors and Culex abundance, which will help me prioritize my existing data for the analysis. I will further investigate the data quality, conduct data cleaning if necessary and determine data characteristics (i.e. distribution of data) of the environmental and Culex specific variables. Finally, I will investigate the statistical model that fits given variables and explains the Culex spp abundance best, depending on the data characteristics and literature review. Options for appropriate models include: zero-inflated negative binomial and Poisson's regression models. After deciding on the appropriate model methodology I will model the Culex abundance as a function of the combination of previously selected environmental varaibles. I hypothesize that environmental drivers such as climate, weather, soil property and vegetation are significant drivers of Culex mosquito abundance. I expect that the analyses of environmental factors impacting the abundance of the Culex spp will provide evidence for better understanding ecological drivers of the RVF disease outbreaks and hence support future predictions of epidemics. On a global view, my work through the proposed scientific exchange will be integrated into the other RVF vector work and together I believe they will provide valuable information to other researchers and policy makers working towards reducing human and animal illness and decreasing socio-economic losses caused by RVF in affected vulnerable communities. I further expect to immensely develop my analytical modelling skills in and knowledge on infectious disease research, to enlarge my scientific network and community through my inclusion within EHA's network and their external partners and to increase my visibility and credibility within the international scientific community by co-authoring on a peer-reviewed scientific publication.