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West Nile virus found in Delaware chickens infected by mosquitoes

Charles MegginsonHeadlines, Health

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West Nile virus has been found in Delaware chickens, infected by mosquitoes.


West Nile virus has popped up in sentinel chickens, the Delaware Department of Natural Resources and Environmental Control announced Tuesday.

The state routinely tests some chickens for mosquito-borne illnesses including West Nile virus and  Eastern Equine Encephalitis. Both can make people sick and, in a few cases, kill humans.

West Nile virus is most commonly spread to people by the bite of an infected mosquito. The virus can cause a brain infection in people, horses and other animals.

There are no vaccines to prevent or medications to treat West Nile in people. 

“Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness,” the CDC says.

Sentinel chickens are housed in 20 monitoring stations statewide. DNREC’s mosquito control section collects blood samples from the chickens weekly, which are then tested for West Nile and Equine Encephalitis antibodies by the Delaware Public Health Laboratory.

Sentinel chickens can become infected if bitten by infected mosquitoes, but don’t develop symptoms.  They do develop antibodies within a week of infection.

DNREC recommends Delawareans take common-sense precautions to avoid mosquito bites, including wearing long-sleeved shirts and long pants when outdoors in mosquito-prone areas, applying insect repellent containing 10 to 30% diethyl toluamide (DEET) in accordance with label instructions and avoiding mosquito-infested areas and times of peak mosquito activity around dusk, dawn and at night.

The public is also advised to drain or remove outdoor items that collect water, such as discarded buckets or containers, uncovered trashcans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flowerpot liners, depressions in boat tarps, clogged rain gutters, corrugated downspout extenders and unused swimming pools.

The Department of Agriculture’s state veterinarian urges horse owners to contact their veterinarians as soon as possible to have horses and other equines vaccinated against both illnesses.  Neither  has a specific drug treatment, and infections in horses are fatal in 70% to 90% of  Equine Encephalitis and in 30% of West Nile cases.

More information about mosquitos and mosquito-borne diseases is available from these resources:

  • For mosquito biology/ecology and control, contact the DNREC Mosquito Control section office in Dover at (302) 739-9917.
  • For requests for mosquito relief in upstate areas from Dover north, contact Mosquito Control’s Glasgow field office at (302) 836-2555.
  • For requests for mosquito relief in downstate areas south of Dover, contact Mosquito Control’s Milford field office at (302) 422-1512.
  • For animal health questions, contact the Delaware Department of Agriculture’s Poultry and Animal Health Section, at (302) 698-4500.
  • To report suspected cases of human WNV, call the Division of Public Health Office of Infectious Disease Epidemiology toll-free at (888) 295-5156.
  • For more information on West Nile virus or Eastern Equine encephalitis, go to www.cdc.gov/ncidod/dvbid/westnile/index.htm


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