A surge in a deadly mosquito-borne virus among horses in South Carolina has been reported by the state veterinarian.
Dr Boyd Parr said 25 cases of Eastern Equine Encephalitis (EEE) had occurred, the first for the year being on June 28.
There have been no cases of West Nile Virus (WNV), another mosquito-borne virus.
Parr urged horse owners to talk to their vets about vaccination.
“These diagnoses are a vivid reminder of the threat that mosquito-borne diseases represent to horses in our state,” Parr said.
“Maintaining protection by vaccinating horses is very important this year.”
During 2012, there were 14 confirmed cases of EEE and seven of WNV in South Carolina.
The EEE virus is maintained in nature through a cycle involving the freshwater swamp mosquito Culiseta melanura, commonly known as the blacktailed mosquito.
Two to three days after becoming infected with 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.
Symptoms usually develop in horses from two to five days after exposure. Symptoms of EEE virus in horses include stumbling, circling, head pressing, depression or apprehension, weakness of legs, partial paralysis, the inability to stand, muscle twitching or death. Nine of every 10 horses infected with EEE virus die from the disease.
Any livestock, including horses, that display neurologic signs must be reported to the state veterinarian at 803-788-2260 within 48 hours, according to the state law.