Second horse with West Nile has recovered

DOVER — A second Delaware horse has tested positive for West Nile Virus, but has recovered, the Department of Agriculture announced today.

The two-year-old filly from Sussex County is the state’s second confirmed case of West Nile Virus since 2003, said Delaware State Veterinarian Dr. Heather Hirst, who heads the Department of Agriculture’s Poultry and Animal Health Section. Delaware’s first equine case of West Nile Virus this year was diagnosed in Kent County in August; that horse has also recovered.

The Department is urging equine owners to vaccinate their horses against West Nile and other mosquito-borne diseases, such as Eastern Equine Encephalitis. EEE was recently detected in a sentinel chicken flock in Sussex County.

Unvaccinated horses are at greatest risk of developing clinical signs from both West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE), which are spread by mosquitoes and can be fatal. Both horses and humans can contract WNV and EEE if bitten by a mosquito carrying the virus, but it is important to note that the viruses are not transmitted between horses or from horses to people. The viruses normally exist in a cycle between mosquitoes and birds, but occasionally EEE can be transmitted from mosquitoes to mammals. Prior to this year, Delaware’s last confirmed equine case of WNV was in 2003, and the last case of equine EEE was in 2005.

Hirst said horse owners should contact their veterinarian immediately if they suspect their horse may be showing signs of WNV or EEE. Symptoms of EEE in horses include fever (102.5-104.5°F), loss of appetite, head pressing, depression or personality change, wobbling or staggering, weakness, blindness, convulsions, muscle tremors in the head and neck, and hind-limb weakness. These signs are also consistent with WNV, although a fever may or may not be present with WNV.

Owners should consult with their veterinarians about best WNV and EEE vaccination programs, Hirst said.

To reduce mosquito breeding, the Department of Natural Resources and Environmental Control advises people to drain or remove items that collect water, such as discarded buckets or containers, uncovered trash cans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in tarps covering boats, clogged rain gutters, downspout extenders, and unused swimming pools.

For more information about:

• Mosquito biology/ecology and control – Contact the Mosquito Control Section’s Dover office at 302-739-9917.

• WNV in humans and related medical issues – Contact the Delaware Division of Public Health at 888-295-5156.

• WNV or EEE in horses and equine vaccines – Contact the Department of Agriculture’s Poultry and Animal Health Section at 302-698-4500 or 800-282-8685 (Delaware only).

• West Nile virus – visit the CDC website,

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Dan Shortridge
Chief of Community Relations
Delaware Department of Agriculture