The Virginia Department of Agriculture and Consumer Services announced on Aug. 27 that another horse from the Hampton Roads area had contracted Eastern Equine Encephalitis via the bite of an infected mosquito and has been euthanized.
The animal, an American Quarter Horse stabled in Chesapeake, is the second to be diagnosed with EEE and the second fatality from the disease in August. Earlier in August a Quarter Horse mare stabled in the Suffolk area also succumbed to the illness, which has a fatality rate of 80-90 percent.
According to the VDACS, both of the horses had an “incomplete vaccination history.”
For full effectiveness horses must receive the initial vaccination and a booster, then be re-vaccinated every six to 12 months, said Elaine Lidholm, communications director for VDACS.
Sometimes called sleeping sickness, Lidholm said EEE is a mosquito-borne illness that causes inflammation or swelling of the brain and spinal cord. Symptoms include impaired vision, aimless wandering, head pressing, circling, inability to swallow, irregular staggering gait, paralysis, convulsions and death.
Once a horse has been bitten by an infected mosquito, it may take three to 10 days for signs of the disease to appear.
VDACS also reported on Aug. 15 that a 9-year-old pony in Fauquire County had tested positive for the West Nile virus. That horse, Lidholm said, was not vaccinated for West Nile but has recovered. Symptoms include a loss of control of bodily movements and partial paralysis in the hind limbs, a dazed appearance and lack of ability to stand.
West Nile has a 30 percent fatality rate in horses.
Dr. Joe Garvin, head of VDACS’ Office of Laboratory Services, said horse owners should check with their veterinarians about vaccinating their animals for West Nile.
“West Nile is a mosquito-borne disease and we generally start seeing our first cases in August and September,” he said. “The disease is usually preventable by vaccination, as is Eastern Equine Encephalitis, so many veterinarians recommend vaccination at least yearly, and in mosquito-prone areas, every six months.”
He added that following the vaccination it takes about six weeks to reach full immunity.
Besides vaccination, recommended prevention methods include eliminating standing water that can provide breeding sites for mosquitoes, the use of insect repellents, and removing animals from mosquito-infested areas during peak biting times, usually dusk to dawn.
Garvin said horse owners should consult their veterinarians if an animal exhibits any neurological symptoms such as a stumbling gait, going down, facial paralysis, drooping or disinterest in their surroundings.