State reports positive mosquitoes for eastern equine virus

The State Mosquito Management Program announced July 16 that mosquitoes trapped in Voluntown on July 10, 2013 have tested positive for eastern equine encephalitis virus (EEE). These results represent the first EEE-positive mosquitoes identified in the state by the Connecticut Agricultural Experiment Station (CAES) this year and the earliest since the trapping program began in 1997.

“While the EEE-infected mosquitoes were Culiseta melanura, a bird-feeding species, identification this early in the season is reason for concern,” said Dr. Theodore Andreadis, chief medical entomologist at the CAES. “Due to recent heavy rains, this species is particularly numerous now and will potentially have a longer season to spread the virus to birds and then mosquito species that feed on birds and people before the weather turns cold in the fall.”

To reduce the risk of being bitten by mosquitoes residents should:

• Minimize time spent outdoors between dusk and dawn when mosquitoes are most active.

• Be sure door and window screens are tight-fitting and in good repair.

• Wear shoes, socks, long pants, and a long-sleeved shirt when outdoors for long periods of time, or when mosquitoes are most active. Clothing should be light colored and made of tightly woven materials that keep mosquitoes away from the skin.

• Use mosquito netting when sleeping outdoors or in an unscreened structure and to protect small babies when outdoors.

• Consider the use of mosquito repellent, according to directions, when it is necessary to be outdoors.

Eastern Equine Encephalitis is a rare but serious disease in people. On average there are six cases each year in the United States. In Connecticut, outbreaks of EEE have occurred sporadically among horses and domestic pheasants since 1938, but no human cases have ever been confirmed. In humans, symptoms of EEE appear 3-10 days after being bitten by an infected mosquito. Most infected people do not develop illness. For those who become ill, inflammation of the brain, encephalitis, is the most dangerous result. The disease gets worse quickly and as many as one-third of people die. In 2012, EEE-positive mosquitoes (all Cs. melanura) were trapped in Chester from Aug. 8 to Sept. 18.

Monitoring and risk assessment for EEE emphasizes mosquito trapping and testing results. The CAES maintains a network of 91 mosquito-trapping stations in 72 municipalities, including Redding, throughout the state. Mosquito traps are set Monday through Thursday nights at each site every 10 days on a rotating basis. Mosquitoes are grouped (pooled) for testing according to species, collection site, and date. Each pool is tested for the presence of viruses of public health importance. Positive findings are reported to local health departments and on the CAES website at

For information on EEE and what you can do to prevent getting bitten by mosquitoes, visit the Connecticut Mosquito Management Program website at

Mosquito pools that test positive for EEE and WNV, as well as human cases of these illnesses, will also be posted on the Connecticut Mosquito Management Program website.