Methods

Based on the previous project BayVirMos, the epidemiological model for West Nile virus transmission was significantly expanded and validated. The spatial resolution of daily forecasts for mosquito-borne infectious diseases in cities was also improved. The model was adjusted to the current situation in Germany by modifying parameters and adding compartments (resident birds, migratory birds, humans).

To validate the warning system, it was extended to outbreak areas in Germany and compared with past West Nile virus infections, especially in eastern Germany. This improves risk assessment for Bavaria as well. Additionally, the epidemiological models for West Nile fever and Chikungunya will be adapted for urban areas. Incorporating modeled temperature data, station data, and remote sensing data increases the spatial resolution. A populationbased model was developed for the common house mosquito (Culex pipiens), and an existing model for the Asian tiger mosquito (Aedes albopictus) was applied.

Evaluation

A target group-specific evaluation of the early warning system (including with doctors and experts) is carried out. This takes place in two steps: First, doctors and experts will be interviewed in qualitative guided interviews. On this basis, their needs when using the online application can be identified and optimization suggestions for revising the platform can be derived. In a second step, the adapted version of the warning system will be subjected to a quantitative evaluation, which will include representatives of vulnerable target groups and other multipliers in addition to people from the fields of human and veterinary medicine. The warning system can thus be tested for user-friendliness. For example, acceptance as well as inhibiting and supporting factors for the day-to-day operation of the online platform will be examined and concrete solution strategies for the future design of the warning system will be developed. The aim is to establish it as a central point of contact for emerging new diseases.

Epidemiological model

In BayByeMos, a process-based, mechanistic epidemic model was developed using environmental and epidemiological data. Before this epidemic model, a population biology model of the disease-transmitting mosquitoes (Culex pipiens) was created. Birds are important hosts that can amplify the virus, while humans and horses can get sick but cannot amplify the virus.

Specific characteristics of the relevant mosquito and bird species were used to parameterize the model. Air temperature, rainfall, and relative humidity are used as input data. Disease case numbers in humans and birds allow for model validation. Spatial and temporal maps of the basic reproduction number (R0) indicate when and where WNV transmission can occur.

The basic reproduction rate indicates how many birds/people, on average, are infected by an infected bird/people in the absence of immunity and without any measures to contain the disease.