Va. Horse Owners Urged to Vaccinate for EEE, WNV, Rabies

Va. Horse Owners Urged to Vaccinate for EEE, WNV, Rabies

Vaccines have been shown to drastically reduce the incidence of EEE, WNV, and rabies in horses.

Photo: Anne M. Eberhardt/The Horse

The Virginia Department of Agriculture and Consumer Services (VDACS) is urging all horse owners to check with their veterinarians for West Nile virus (WNV), Eastern equine encephalitis (EEE), and rabies vaccination recommendations for their animals. Virginia only had one confirmed case of WNV and one of EEE in 2013, although the number of horses affected in other states was much higher.

State officials are concerned that horse owners could be lulled into inaction by the lack of disease activity last year and neglect vaccination this year.

“Timely vaccination has been shown to decrease WNV and EEE disease incidence,” said Charles Broaddus, DVM, program manager for VDACS Office of Veterinary Services. “Without vaccination, we would expect to see many more infected horses, so we still urge horse owners to consider EEE and WNV vaccination. We believe that in most cases, private veterinarians will recommend them for their clients.”

Vaccines have been shown to drastically reduce the incidence of WNV and EEE in horses. They are effective for six to twelve months, so horses should be revaccinated at least annually. In areas where the disease occurs frequently, most veterinarians recommend vaccination every six months. For the vaccine to be effective it must be handled and administered properly and be given at least two weeks before the horse is exposed to the virus. Additionally, to stimulate full immunity, horses must be vaccinated twice, about 30 days apart, the first year they are vaccinated. Other prevention methods include destroying standing water breeding sites for mosquitoes, using insect repellents, and removing animals from mosquito-infested areas during peak biting times, usually dusk to dawn.

Broaddus also suggests that owners consider rabies vaccinations for their horses. The number of rabies cases in horses has grown in the past few years. In fact, recently rabies cases have exceeded cases of WNV or EEE.

Rabies vaccines are also very effective and vaccinating horses annually can prevent rabies in both horses and humans. In addition to taking measures to decrease the likelihood that horses will be exposed to rabies, routine rabies vaccination is a very important aspect of disease prevention. Virginia did not report any horses positive for rabies in 2013, but had four positive in 2012.

All three of these diseases—EEE, WNV, and rabies—cause neurologic signs in horses, such as staggering, circling, depression, loss of appetite, and sometimes fever and blindness. There is no cure for these diseases, which can kill anywhere from 30% (WNV) to 90% (EEE) to 100% (rabies) of infected horses. Humans can become infected with rabies by handling a rabid horse but cannot become infected with EEE or WNV by handling an infected horse, nor can a horse acquire the virus from another infected horse. The presence of an infected horse in the area indicates that mosquitoes carrying EEE or WNV are present and those insects pose a threat to both humans and horses.

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