EEE Detected in Sentinel Chickens in Each County


Eastern Equine Encephalitis (EEE), a potentially serious illness, has been detected in sentinel chickens monitored for mosquito-transmitted diseases in Delaware. The Delaware Division of Public Health Laboratory reported to DNREC’s Mosquito Section that four chickens recently tested positive for EEE from three of the 20 sentinel chicken stations monitored by Mosquito Control. The three stations are located in southwestern New Castle County, east-central Kent County, and southeastern Sussex County.  

In response to these recent EEE detections, the Mosquito Control Section will increase mosquito population surveillance in areas where the EEE detections have occurred, and take mosquito control actions as warranted to include possible aerial spraying and/or fogging with a spray truck.

Anyone in an area where the virus is present can be infected with EEE, with people who are exposed to high numbers of mosquito bites at the highest risk. The Mosquito Control Section encourages people to avoid mosquito bites and lessen their chances of contracting a mosquito-transmitted disease by:

  • Properly using insect repellent containing DEET or another EPA-recognized ingredient whenever outdoors
  • Covering up exposed skin as much as possible by wearing long-sleeved shirts and pants
  • Avoiding known high mosquito population areas or being outside during times of peak mosquito activity, typically dawn and dusk.

Eastern Equine Encephalitis is a rare, potentially fatal viral disease spread by mosquitoes that can affect both people and horses, and is considered one of the more serious mosquito-transmitted illnesses. While not as common as West Nile Virus (WNV), another mosquito-transmitted disease in Delaware affecting both people and horses, EEE is more virulent than WNV, with a higher fatality risk.  Although WNV is usually found before EEE in the summer in Delaware, no sentinel chickens or wild birds have tested positive for WNV yet this year. No human or equine cases of EEE or WNV have been reported to date this year in Delaware. Although EEE and WNV vaccines are available for horses, no such vaccines are available for people.

Many people infected with EEE have no apparent signs of illness, according to the Delaware Division of Public Health. Symptoms of EEE often appear four to 10 days after being bitten by an infected mosquito. Severe cases of EEE can involve encephalitis, an inflammation of the brain, beginning with the sudden onset of headache, high fever, chills, and vomiting. The illness may then progress into disorientation, seizures, or coma. Approximately 33 percent of EEE cases in people lead to death, and many of those who do survive can experience significant brain damage or other long-term effects. Those over age 50 and under age 15 appear to be at greatest risk for developing severe disease when infected with EEE. There is no specific treatment for EEE, with care based on symptoms. If you think you or a family member may have contracted EEE, it is important to consult your healthcare provider for proper diagnosis.

In addition to avoiding mosquito bites, the Mosquito Control Section advises residents to also reduce mosquito producing habitat on their individual properties and in communities and neighborhoods by draining or removing items that collect water, such as discarded buckets or containers, uncovered trash cans, stagnant birdbaths, unprotected rain barrels or cisterns, old tires, upright wheelbarrows, flower pot liners, depressions in tarps covering boats, clogged rain gutters, corrugated downspout extenders, and unused swimming pools.

The Mosquito Control Section also encourages residents to report intolerable numbers of biting mosquitoes by calling the numbers below between 8 a.m. and 4 p.m. Monday through Friday. Callers after business hours or during weekends or holidays should leave their name, phone number, address, and a brief message.

  • Glasgow Office, serving all of New Castle County and northern Kent County, including the Dover area: 302-836-2555
  • Milford Office, serving southern Kent County and all of Sussex County: 302-422-1512

The public can also call these numbers to report suspected WNV-stricken wild birds, with special emphasis on crows, blue jays, cardinals, robins, hawks, and owls.

For more information about:

  • Mosquito biology/ecology and control – Contact the Mosquito Control Section’s Dover office at 302-739-9917.
  • WNV or EEE in humans and related medical issues – Contact the Delaware Division of Public Health at 888-295-5156. 
  • Animal health questions – Contact the Delaware Department of Agriculture, Poultry and Animal Health Section, at 800-282-8685.

For more information about Eastern equine encephalitis or West Nile Virus, visit the CDC website,