Morris County Horse Dies Of Rare Disease Affecting Brain

An 8-year-old Morris County mare was euthanized on August 13 after the horse tested positive for Eastern Equine Encephalitis, according to the New Jersey Department of Agriculture. EEEV is a virus that can ravage the neurological systems of humans, horses, and some birds.

The Morris County case is the first reported in New Jersey for the year, but other states have reported cases of EEEV, including South Carolina, with at least 14, according to The Horse magazine. The disease is most common on the eastern side of the United States at about this time, peaking from late July through early October. In fact, the majority of EEEV cases have been reported in Florida, Georgia, Massachusetts, and New Jersey.

EEEV is a virus that is spread by the bite of an infected mosquito, like many other diseases including West Nile and Zika. According to the CDC, the virus multiplies and survives through a cycle between Culiseta melanura mosquitoes and various avian hosts in freshwater hardwood swamps.

When an infected mosquito then bites a horse, or a human, the virus multiplies, disables, and sometimes kills the new host. Both horses and humans are dead ends for the virus, meaning these species cannot spread the disease to others of their kind, nor spread the virus through other uninfected vectors.

The virus attacks the central nervous system, causing symptoms like fever, depression, facial paralysis, lack of appetite, gait abnormalities, blindness, and behavioral issues like aggression. The virus can sometimes be fatal for horses, but in cases where horses survive, there are usually long-term impairments. A vaccine for horses, available commercially, can usually prevent a horse from developing the disease. The mare euthanized in Morris County had not been vaccinated.

“Horse owners need to be vigilant in vaccinating their animals against diseases spread by mosquitoes,” said New Jersey Secretary of Agriculture Douglas H. Fisher. “Vaccinated animals are much less likely to contract deadly diseases such as EEE and West Nile Virus.”

Image used via gustavobelemmi, Morguefile, used under Creative Commons.