Climate Change and the Risk of Highly Pathogenic Avian Influenza Outbreaks in Birds

In this paper, we examine the association between climate change and outbreak probability of Highly Pathogenic Avian Influenza A virus (HPAI H5N1) in birds. Climate change is a potential factor for the recent spread of H5N1 outbreaks because it can directly alter the conditions involved in persistence of the virus and disease transmission. Also it can contribute indirectly by changing wild bird migration patterns. Econometric analyses using a dynamic Probit model over monthly data from January 2004 to December 2008 found that a 1% rise in winter total precipitation increases the risk of HPAI H5N1 outbreaks by 0.26%. Spring mean temperature was also found to have positive and significant impacts. Our findings are robust across different model specifications and under out-of-sample tests. Using historical data we find the realized climate change of the last 20 years partly explains the recent expansion in outbreaks. Under future climate change projections, we find that countries having higher projected spring temperature or more winter precipitation or both, such as Japan and Romania, will have large increases in outbreak probabilities. This suggests that climate change may play an even greater role in the future, although magnitudes will vary across countries and climate projections. From a policy perspective, future climate conditions may give rise to a need for different disease control and prevention strategies.