Suspected Equine Case of West Nile Virus in Connecticut

The State of Connecticut Mosquito Management Program announced Aug. 24 that a horse in West Granby has exhibited clinical signs consistent with West Nile virus (WNV) infection and preliminary laboratory results indicate a recent exposure to the virus. Additional testing is underway to confirm the diagnosis. Consistent with the State West Nile Virus Surveillance and Response Plan, the State is not spraying, but is recommending the public take the necessary personal precautionary measures to reduce mosquito bites, and reduce their animals’ exposure to mosquitoes.

West Nile virus is spread by the bite of an infected mosquito. It is not transmitted directly to people from animals, birds or other people. The same mosquitoes that can transmit WNV to a horse can also transmit the virus to a person. Horses with WNV infection pose no threat to people or other horses. A sick horse should be evaluated by a veterinarian to rule out other possible diseases, such as rabies.

The Connecticut Department of Agriculture has submitted additional samples from the horse to the National Veterinary Services Laboratory (NVSL) in Ames, Iowa, for confirmation of the presence of WNV. The Connecticut Agricultural Experiment Station set up additional mosquito traps on Monday, Aug. 27 in the area of the sick horse with test results within 10 days.

On Aug. 16, the owner recognized the horse, a 22-year old mare, as having decreased appetite, acting lethargic and being unsteady. The horse is responding to veterinary treatment and is improving. To date, twelve horses and one cat have been tested for WNV infection through Connecticut’s Domestic Animal and Poultry Surveillance program. Eleven horses and the one cat have tested negative for WNV. In 2000, Connecticut had seven confirmed cases of WNV infection in horses, three horses died and four horses recovered.

While the State of Connecticut is not spraying, some municipalities have made the decision to spray in their towns as part of their efforts to reduce nuisance mosquito numbers. The State is asking the public to continue eliminating mosquito breeding habitats and protecting themselves against mosquito bites. The State is asking the public to continue reporting sightings of dead birds throughout the summer and fall to their local health departments. Results of wild bird testing, dead bird reporting, mosquito trapping and testing, and domestic animal and human cases identified are summarized weekly and distributed by DEP on Wednesdays.

DEP reports important WNV-related information to the public through press releases, and posting to an enhanced web site and information line:

* DEP’s Web site at

* 24-hour (toll-free in Connecticut) recorded mosquito information line 866/WNV-LINE (1-866-968-5463) or 860/424-4184.

For local WNV information or to report dead birds:

Granby: Farmington Valley Health District 860/676-1953.

The State of Connecticut Mosquito Management Program is an interagency program consisting of the Department of Environmental Protection (program administrator), The Connecticut Agricultural Experiment Station, the Department of Public Health, the Department of Agriculture, and the University of Connecticut Department of Pathobiology and Veterinary Science.

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