{"id":21942,"date":"2024-09-12T09:25:29","date_gmt":"2024-09-12T14:25:29","guid":{"rendered":"https:\/\/vetmed.tamu.edu\/news\/?p=21942"},"modified":"2025-12-25T22:50:50","modified_gmt":"2025-12-26T04:50:50","slug":"west-nile-virus-eastern-equine-encephalitis","status":"publish","type":"post","link":"https:\/\/vetmed.tamu.edu\/news\/pet-talk\/west-nile-virus-eastern-equine-encephalitis\/","title":{"rendered":"Say \u2018Neigh\u2019 To West Nile Virus, Eastern Equine Encephalitis"},"content":{"rendered":"
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As summer turns to fall, most of the U.S. officially enters peak mosquito season. And with peak mosquito season comes a rise in mosquito-borne illnesses, including West Nile Virus and Eastern Equine Encephalitis (EEE).<\/p>\n\n\n\n

Because these vector-borne diseases affect multiple species of animals, including humans, Dr. Amanda Trimble<\/a>, a clinical assistant professor of equine internal medicine at the Texas A&M College of Veterinary Medicine & Biomedical Sciences, explains how West Nile Virus and EEE affect horses and provides tips to owners for helping their equine companions prevent these diseases. <\/p>\n\n\n\n

What Are West Nile Virus And EEE?<\/h3>\n\n\n\n

While West Nile Virus and EEE are viral infections that most commonly affect horses, humans, and birds, neither is zoonotic (meaning you can\u2019t get it from your horse), according to Trimble. <\/p>\n\n\n\n

\u201cNeither disease is contagious directly to humans from horses and vice versa; however, cases seen in either species may indicate that the diseases are present in the local mosquito population,\u201d Trimble said. \u201cBoth viruses need mosquito vectors to be spread, meaning that a mosquito must collect blood from an infected carrier of the virus \u2014 typically a bird \u2014 and then bite a horse or human in order for the disease to spread.\u201d<\/p>\n\n\n\n

Because West Nile Virus and EEE depend on mosquitoes to spread, Trimble said it is important for horse owners to be mindful of mosquito season. <\/p>\n\n\n\n

\u201cPeak incidence follows mosquitoes \u2014 which typically peak between July and October for most of the United States,\u201d she shared. \u201cBut because Texas is always warm, mosquito season never really ends.\u201d<\/p>\n\n\n\n

As a result, Trimble recommends Texans help protect their horses from West Nile Virus and EEE year-round.<\/p>\n\n\n\n

How Do West Nile Virus And EEE Affect Horses?<\/h3>\n\n\n\n

Both viruses can be fatal for horses. <\/p>\n\n\n\n

\u201cAbout one-third of affected horses \u2014 typically those that are unvaccinated \u2014 may die from West Nile Virus, while more than 90% of unvaccinated horses die from an EEE infection,\u201d Trimble said. \u201cWith both, disease and clinical signs may still occur in horses that are vaccinated but are usually much less severe. However, horses that survive may have permanent neurological deficits.\u201d<\/p>\n\n\n\n

Trimble recommends owners contact a veterinarian if they suspect their horse has either virus based on the following symptoms:<\/p>\n\n\n\n

West Nile Virus Symptoms<\/p>\n\n\n\n