Preventative measures are the best way to protect a vulnerable equine inventory.
There have been 30 confirmed positives, and two suspected cases, of Eastern equine encephalitis this summer in the state of South Carolina.
The number of cases of EEE continues to be prevalent, as there were seven cases diagnosed during the five day period from Aug. 5 to 9, and five more during the past week, said Dr. Adam Eichelberger, Clemson University director of animal health programs. The first positive confirmed case of West Nile Virus was diagnosed this past week in Lancaster County. There haven't been any confirmed positive cases of either EEE or WNV in Aiken County.
However, there are ways horse owners can preclude their horse from being diagnosed with the vector-borne pathogen, which is usually 90-95 percent fatal.
Vaccinations and booster shots are critical in maintaining the best protection, said Eichelberger.
“Preventative vaccines are very effective,” said Eichelberger. “Horses that have never been vaccinated or have an unknown vaccine history will have to be boostered four to six weeks after the first vaccine. The series of injections is required to be effective and protective. In South Carolina, we recommend that horses are vaccinated twice yearly (every six months) for Eastern-Western equine encephalomyelitis and West Nile virus. These vaccines usually come in single doses or multiple combinations known at EWT, EWT/WN or EWT/FR. The 'T' in the abbreviation is short for tetanus, which is also a very important vaccine for horses.”
Mosquito prevention plays a critical role in preventing the disease, said Eichelberger. Eastern equine encephalitis is spread by infected mosquitoes.
“Horses that are sick with EEE, don't get sick from other horses that have EEE,” said Eichelbeger. “They get sick from mosquitoes that are infected with EEE.”
If a horse owner suspects their horse may be infected with Eastern equine encephalitis, they should contact their local veterinarian and make an appointment for evaluation and treatment, said Eichelberger.
There are clinical signs horse owners should be aware of, if they suspect their horse may be infected with the virus. Symptoms can include a change in the way a horse presents itself, loss of appetite, depression, lethargy, severe fever, acting out of the ordinary, incoordination, inability to swallow and drooling, said Eichelberger.
The incubation of the disease can be as short as one week but as long as three weeks.
“Encephalitis means inflammation in the central nervous system, basically the horse's brain is inflamed,” said Eichelberger. “Inflammation of the brain leads to the horse becoming neurologic. Horses initially febrile (elevated temperature) often becoming depressed or sluggish. Another name for EEE is sleeping sickness.”
Horses infected with the virus should be isolated, said Eichelberger.
“Horses should be approached with extreme caution because of concerns of large unstable animals falling on people, animals or structures,” said Eichelberger.
Ben Baugh has been covering the equine industry and equestrian sport for the Aiken Standard since 2004.