What type of hosts typically sustain the transmission cycles of EEE?

The transmission cycles of Eastern equine encephalitis (EEE) are primarily sustained by wild birds. These avian species, particularly certain types of songbirds, serve as the main hosts for the EEE virus, allowing the virus to replicate and be transmitted to mosquitoes. Mosquitoes, especially those in the genus Culiseta, then feed on these infected birds, facilitating the transmission of the virus to other hosts, including mammals and humans.

While horses are considered an important indicator of EEE activity in the environment and can become infected—leading to severe disease and often death—they do not play a significant role in maintaining the virus within its natural transmission cycle. Instead, they are incidental hosts, meaning they do not contribute to the propagation of the virus in mosquito populations, but rather become infected due to bites from mosquitoes that have fed on infected birds.

On the other hand, humans and small mammals are also considered incidental hosts for EEE, as they can become infected if bitten by infected mosquitoes but, like horses, do not support the virus's lifecycle. The natural reservoir hosts for EEE remain predominantly the wild birds, which highlights their critical role in the ecology of the virus. Thus, identifying wild birds as the primary hosts through which E