NewsDesk  @infectiousdiseasenews

South Carolina officials report the first case this year in the state of Eastern Equine Encephalitis (EEE) in Sumter County. According to State Veterinarian Michael J. Neault, the 18-year-old gelding was euthanized due to his deteriorating condition.


The animal’s vaccination status was unknown.

Neault reminded horse owners to work with their veterinarian to create an appropriate vaccination schedule to protect their animals from EEE, West Nile virus (WNV), and rabies.

Borne by mosquitoes, these diseases have a very high mortality rate in infected, unvaccinated horses – between 30 and 40 percent for West Nile and 90 percent for EEE. However, widespread vaccination has kept the number of cases comparatively low in South Carolina compared to nearby states.

Likewise, mosquito control is an important precaution. Both EEE and West Nile Virus are maintained in nature through a cycle involving the freshwater swamp mosquito, Culiseta melanura, commonly known as the black-tailed mosquito.

The EEE and WNV viruses are mosquito-borne and fast-acting. Symptoms of EEE in horses usually develop from two to five days after exposure. The symptoms include stumbling, circling, head pressing, depression or apprehension, weakness of legs, partial paralysis, the inability to stand, muscle twitching or death.