Where is eastern equine encephalitis (EEE) most commonly found?

Eastern equine encephalitis (EEE) is most commonly found along the Gulf Coast and eastern U.S. coastline due to the specific habitats and ecological conditions present in these areas that are conducive to the breeding of the mosquitoes that carry the virus.

These regions often have climates and water sources that support the life cycles of the mosquitoes that act as vectors for EEE, particularly species such as Culiseta melanura, which thrive in freshwater swamps and marshes. The wetlands found along the Gulf Coast and the eastern seaboard provide ideal breeding grounds for these mosquitoes, increasing the likelihood of EEE transmission to both humans and equines.

In contrast, urban areas worldwide are generally less favorable for the specific vectors associated with EEE because urbanization often reduces the availability of natural habitats needed for mosquito breeding. Arid regions and high altitude environments typically lack the necessary water bodies and warmer temperatures that support the survival and reproduction of EEE-carrying mosquitoes, making these areas less likely sources of the virus. Thus, the specific geographic distribution of EEE is heavily influenced by the presence of suitable habitats for its mosquito vectors, predominantly located in the Gulf Coast and along the eastern U.S. coastline.