November 5, 2021

Eastern Equine Encephalitis and West Nile Virus detected in sentinel chickens

MOBILE, Ala. – Sentinel chickens used by the Mobile County Health Department (MCHD) to detect mosquito-borne diseases in the community have tested positive for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV). Both are a form of mosquito-borne encephalitis.

EEE has been confirmed by laboratory results, according to Dr. Bernard H. Eichold II, Health Officer for Mobile County. The coop was located in the 36582 ZIP Code.

WNV was confirmed in a coop located in the 36611 ZIP Code. Humans with WNV and other mosquito-borne diseases often have symptoms of high fever, severe headache, nausea, stiff neck, confusion, muscle weakness, paralysis, disorientation, and seizures that are severe enough to require medical attention, Eichold said.

“There are no health benefits to being bitten by a mosquito,” Eichold said. “Don’t let your guard down. EEE has a human mortality rate of between 50 to 75 percent, while West Nile Virus is between 3 to 15 percent. EEE is a very serious mosquito-borne illness.”

The risk of encephalitis spread by mosquitoes is highest from August through the first freeze in the fall, Dr. Eichold said. MCHD’s Vector Services will increase spraying and conduct door-to-door surveys in the immediate areas. Inspectors will also attempt to trap adult mosquitoes and test them for the presence of EEE and WNV.

Blood is drawn from the sentinel chickens every Monday by Vector Services, and the samples are sent to a lab in Tampa, Florida. The results of the tests are available later in the week.

Health officials warn that it is extremely important that people taking part in outdoor activities make every effort to reduce their exposure to mosquitoes. Recommendations include:
• Use an Environmental Protection Agency-registered repellent with DEET.
• Wear long-sleeved shirts and long pants.
• Stay and sleep in places with air conditioning or window and door screens.
• Remove standing water around your home.

EEE and WNV are transmitted from bird to mosquito to the bird. Mosquitoes can spread these viruses by feeding on the blood of infected birds and then biting another host animal or mammal such as a human or a horse.

Although humans and horses can become ill from the infection, the diseases cannot be spread from people or horses. The likelihood of transmission to humans and horses can be decreased by personal mosquito avoidance and the use of an EEE or WNV vaccine in horses. There is no vaccine available for humans.

For approximately 30 years, Vector Services has monitored encephalitis in sentinel poultry flocks strategically placed in 13 coops throughout the county to detect the presence of viruses carried by mosquitoes. Mosquitoes also are trapped and tested for WNV, EEE, and St. Louis Encephalitis.

To report an issue with mosquitoes, call Vector Services at 251-690-8124. To learn more, please visit https://mchd.org/vector-control.