What is the most frequently occurring mosquito-borne disease in the United States?

West Nile Virus is the most frequently occurring mosquito-borne disease in the United States. This virus was first identified in the U.S. in 1999 and has since become widespread across the country. It is primarily transmitted to humans through the bite of infected mosquitoes, particularly species that thrive in urban areas and are commonly found around human habitation.

In contrast, while Eastern equine encephalitis, Malaria, and Zika Virus are all significant mosquito-borne diseases, they do not occur with the same frequency or spread as West Nile Virus. Eastern equine encephalitis is relatively rare, and while it can have severe consequences when contracted, it typically affects a much smaller number of individuals. Malaria is not endemic to the U.S., although rare cases do happen, usually related to travelers returning from areas where malaria is common. The Zika Virus garnered attention due to its association with severe birth defects when contracted during pregnancy; however, its transmission rates in the broader U.S. population have been lower compared to West Nile Virus since the 2016 outbreak.

Therefore, West Nile Virus stands out due to its established presence and transmission patterns in the U.S., making it the most commonly reported mosquito-borne illness.