Risk of infection with West Nile virus in Germany

WNV is a flavivirus and is transmitted by mosquitoes between wild birds. Mosquitoes infected by birds can also transmit the virus to humans. Outbreaks have been occurring in southern Europe in summer for a long time. So far, summer temperatures in Germany have not been warm enough throughout the day and night for transmission by the widespread common mosquito. However, human cases of infection have also been reported in Germany since 2019. West Nile fever usually heals without complications. However, late effects are common in patients who have developed inflammation of the brain, and people with pre-existing conditions or older people can die due to the West Nile virus penetrating the nervous tissue.

Oliver Chinonso Mbaoma, Dr. Stephanie Thomas and Prof. Dr. Carl Beierkuhnlein from the Department of Biogeography at the University of Bayreuth have developed a model that can be used to simulate the spatial and temporal risk of infection with WNV in Germany. The model is based on environmental data such as daily temperature and precipitation as well as epidemiological data and was tested using human and animal WNV cases from the last five years. In addition, the research team included characteristics of mosquitoes and bird species that are particularly important for the transmission of WNV in the calculations.

The model results provide a good representation of previous areas with WNV cases and show further areas in the west of North Rhine-Westphalia, the Upper and Middle Rhine and individual districts in Bavaria where transmission would be possible from July to the end of October from a climatic perspective.

“Our results lay the foundation for an early warning system for infectious diseases whose transmission is favored by rising temperatures. The model can help the public health service to take preventive measures. In addition, the medical profession can adapt differential diagnostics based on the risk situation,” says Thomas.

The research work was funded by the Bavarian State Ministry of the Environment and Consumer Protection and the Bavarian State Ministry of Health and Care via the BayByeMos project (AP-2411-PN 21-14-V3-D22827/2022) as part of the joint project “Climate Change and Health II” (VKG II).