The title says it all. Here are the most recent maps from WormsAndGermsMap showing equine cases of West Nile virus and Eastern Equine Encephalitis (EEE) virus infection. As with any surveillance, the maps only capture a percentage of the true number of cases, but looking at the geographic distribution and trends in date-of-onset can still be informative.
West Nile cases in horses as of 28-Sep-2016
Eastern Equine Encephalitis (EEE) cases in horses as of 28-Sep-2016