Vaccinate Horses for Sleeping Sickness and West Nile Virus Auburn, April 16, 2004 --- Mosquitoes will become a growing problem in Alabama as the weather continues to warm. For that reason, an animal scientist with the Alabama Cooperative Extension System said it's important that horse owners take precautions to protect their animals from a number of mosquito- borne diseases. Dr. Cindy McCall, an Extension equine specialist, said there is little reason for a horse to contract eastern equine encephalomyelitis, also known as sleeping sickness, or West Nile virus because vaccines are available. "Horse owners in Alabama should vaccinate their horses now for sleeping sickness and West Nile virus if they have not already done so," said McCall. "Horses should get a second vaccination for these diseases later in the year to boost their immunity." She added that the best time to revaccinate is mid to late summer, such as in August, when some cases of EEE typically are seen in Alabama. Revaccinating before this time will increase protection against the disease. EEE, a viral disease spread by certain kinds of mosquitoes, is almost always fatal in horses and is characterized by the progressive failure of the horse's central nervous system. Symptoms in horses include depression, high fever, hypersensitivity to sound and touch, apparent blindness, wandering and paralysis. "Horse owners should check with their vets about vaccination schedules," said McCall. "But I would revaccinate any horse whose last vaccination was more than four months earlier." Pregnant mares should be vaccinated before foaling. This allows the mare to pass her immunities to the nursing foal. Consult with a vet about first vaccinations for foals. WNV was first identified in the United States in 1999 in New York and has been spreading for the last five years. It is also a virus spread by mosquitoes that get the disease from infected birds. WNV generally does not have as high a mortality rate in horses as EEE, but some horses that contract WNV will die or have to be euthanized. Both EEE and WNV can affect people as well. McCall emphasized that humans cannot contract the disease directly from horses. "If a person contracts these diseases, it's from an exposure to the mosquitoes that carry the virus," said McCall. The horse is a terminal host for the virus. This means that an infected horse cannot infect another animal. Mosquito control measures such as using insect repellents on horses and emptying stagnant water pools may help slow the diseases’ spread. Horse owners may want to stable animals to limit their exposure to mosquitoes. People can limit their exposure potential by using insect repellents formulated for humans and avoiding outdoor activities when mosquitoes are most active such as late afternoon and early evening. ###