Encyclopedia of Environmental Health (Second Edition): Vector Borne Disease and Climate Change

Recent years have seen major shifts in a number of vectorborne diseases with West Nile virus appearing in New York and then spreading through much of North America, Chikungunya virus causing an outbreak in Italy, and Bluetongue virus causing a livestock disease spreading through northern Europe. It is perhaps expected that climate change will be invoked as a major driving force for these epidemic shifts. Climate variables such as rainfall and temperature do have demonstrable effects on the epidemiology of this group of pathogens. However, the actual effect is highly site specific suggesting that other factors play an equally important role. Climate change could affect vectorborne diseases in a number of ways. However, the evidence that climate change is driving changing epidemiology is far from clear and often contradictory. Probably the clearest evidence comes from increased disease incidences seen in the aftermath of weather-related disasters such as floods and hurricanes. Certainly the epidemiology of both malaria and dengue fever is sensitive to local climate effects. However, attempts to definitively link long-term trends in particular diseases to climate change are problematic. This is likely to be because of failure to build models that consider the wide range of factors that influence disease epidemiology.