Climate is one of the factors that influences the distribution of vector-borne diseases. "Vectors” are living organisms that can transmit infectious diseases between humans or from animals to humans; for example, fleas, ticks, and mosquitoes can all spread pathogens that cause illness. The Disease Maps page hosted by the U.S. Geological Survey provides seasonal tracking of seven vector-borne diseases in the United States and territories: West Nile Virus, St. Louis Encephalitis, Eastern Equine Encephalitis, Western Equine Encephalitis, La Crosse Encephalitis, Powassan Virus, Dengue Fever (locally acquired), and Dengue Fever (imported).

From the landing page, users can navigate to maps showing current activity of each disease within the United States. These map pages also include background information about the disease, historical maps of activity in previous years, FAQs, and links to additional resources.