West Nile virus: when will an outbreak occur and how can we prevent it?

Emerging infectious diseases are a concern for wildlife and human health. To understand, prevent, and control infectious diseases, it can be helpful to use mathematical models. West Nile virus is a new infectious disease in North America. The virus is transmitted back and forth continually between mosquitoes and birds, and occasionally is transmitted from mosquitoes to humans. We developed a mathematical model to represent the West Nile virus outbreak in North America. We then used the model to determine whether it would be more effective to remove mosquitoes or remove birds to prevent disease outbreaks. Our model showed that reducing mosquito abundances would help prevent an outbreak. Reducing bird abundances, however, would have the opposite effect, increasing the chance of an outbreak.