A preemptive measure could be the difference between life and death.

South Carolina was the nation’s leader in 2013 in the number of horses diagnosed with Eastern equine encephalitis, with 48 of the 49 horses infected with the disease succumbing to its effects.

There were three horses diagnosed with the virus in Aiken County in 2013.

How is this virulent vector-borne virus spread?

What can be done to reduce the chance of your horse acquiring the virus, a contagion that is carried by the black-tailed mosquito?

“Vaccination is the most effective prevention,” said Adam Eichelberger, director of animal health programs at Clemson University. “Two to three days after becoming infected with the EEE virus, a mosquito becomes capable of transmitting the virus. Infected mosquitoes that feed on both birds and mammals can transmit the disease to horses and humans.”

Eichelberger also recommends spraying insect repellents, removing standing water that harbors larvae and reducing activity at times when mosquitoes may be most active.

“In South Carolina, we recommend EEE, West Nile virus, tetanus and rabies as core vaccines,” said Eichelberger. “Some horses may need influenza, rhino and strangles vaccinations, based on their activity and risk of exposure.”

Horse owners should be vigilant; if they observe their horse exhibiting any symptoms redolent of the disease, they should understand the consequences, Eichelberger said.

The symptoms will usually begin to manifest themselves two to five days after exposure, he said.

“Symptoms in horses include stumbling, circling, head pressing, depression or apprehension, weakness of legs, partial paralysis, the inability to stand, muscle twitching or death,” said Eichelberger. “Nine out of 10 horses infected with the EEE virus will die from the disease.”

According to state law, any livestock displaying neurological symptoms, tumbling, circling, head pressing, depression or apprehension, must be reported to the state veterinarian at 803-788-2260 within 48 hours, Eichelberger said.

Ben Baugh has been covering the equine industry and equestrian sport for the Aiken Standard since 2004.