07/25/06 — Horse owners on lookout for mosquito-borne illness

View Archive

Horse owners on lookout for mosquito-borne illness

By Andrew Bell
Published in News on July 25, 2006 1:55 PM

Horse owners are being reminded to have their animals vaccinated against mosquito-borne diseases that pose a threat during the hot months of summer.

The state Department of Agriculture and Consumer Services reported the first case of eastern equine encephalomyelitis last week. A 3-year-old Tennessee Walking Horse in Columbus County contracted the disease and had to be euthanized.

Eileen Coite, livestock agent for the Wayne County Cooperative Extension Service, said encephalomyelitis is a neurological disease that affects a horse's brain and central nervous system. The disease is transmitted through insect bites, mostly from mosquitoes.

Equine encephalomyelitis has three strains: eastern, western and Venezuelan. Although it is possible for a horse to contract the western and Venezuelan strains, the eastern strain is more prevalent in this area, Ms. Coite said.

When a horse is infected, it will usually begin to eat less and have trouble with its coordination and steadiness on its legs, she said. In extreme cases, the horse falls down and can't get up.

Once a horse contracts the disease, veterinarians do not have any kind of "real treatment protocol" to fight it, Mrs. Coite said.

"They usually have to do what we call supportive care. All that can do is minimize the symptoms, but there's no magic drug to treat the disease," Ms. Coite said.

Although it is possible for a horse to survive a bout of encephalomyelitis, Ms. Coite said it is rare for a horse to survive if it contracts the eastern strain of the disease.

The disease is similar to West Nile Virus, a related disease which humans can contract from mosquitoes. When a human contracts West Nile Virus, doctors provide the patient with drugs that ease the symptoms and hope for the person's immune system to fight the disease. That is pretty much the only option a veterinarian has with a horse that has encephalomyelitis.

Although a horse cannot transmit the disease to a person, a mosquito can spread encephalomyelitis to humans, Dr. Robert Rigsby of Golds-boro Veterinary Hospital said.

Much like other neurological viruses, human symptoms of encephalomyelitis include showing odd behavior, such as aggression or depression, Dr. Brian Stuber of the Berkeley Veterinary Clinic said.

A 9-year-old girl in Buncombe County was treated for La Cross encephalitis last week. It was the first case reported this year.

Equine encephalomyelitis cases are more prevalent when the area experiences heavier amounts of rain, which provides a breeding ground for mosquitoes. North Carolina experienced a large outbreak of eastern equine enceph-alomyelitis in 2003, when the region was inundated almost daily by thunderstorms.

Dr. Stuber said an enceph-alomyelitis vaccination is essential for a horse.

"It's as basic for a horse as a rabies vaccination is for a dog or cat," Dr. Stuber said.

Although county officials haven't seen an epidemic of the disease in many years, Ms. Coite said area livestock owners should not take the risk of failing to have their horses vaccinated twice a year.

"We suggest a fall and spring vaccination to carry them through the year," Ms. Coite said.