SEIR-Metapopulation model of potential spread of West Nile virus

In 2018, West Nile Virus (WNV) was detected for the first time in Germany. Since the first detection, 36 human cases and 175 cases in horses and birds are detected. The transmission cycle of West Nile Virus includes birds and mosquitoes and as dead-end hosts — humans and horses. Spatial dissemination of the disease is caused by the movements of birds and mosquitoes. It should be noted that the vector activity and the spread of WNV are not entirely intertwined but there is a greater scale of overlap between it. The dissemination process is rather complicated and it can not only be attributed to different weather driven factors like temperature but also other biological factors i.e. vector competency, habitat suitability etc. In our current study, we have restricted our modelling effort only to temperature dependent to simplify the modelling assumptions. While the activity and movement of mosquitoes are depending mainly on temperature, in the birds there is a complex movement pattern caused by local birds and long-range dispersal birds. To this end, we have developed a metapopulation-network model to delineate the potential spatial distribution and spread of WNV across Germany. Our model combines vector, local birds, and long-range dispersal birds contact networks. We have assumed different distance dispersal kernels models for the vector and avian populations with the intention to include short and long-range dispersal. The model includes spatial variation of mosquito abundance and the movements to resemble the reality.