EEE Virus Found in Central Square: Oswego County Will Conduct Aerial Spraying

CENTRAL SQUARE – The Oswego County Health Department was notified by the State Health Department late Tuesday, Sept. 4, that the Eastern equine encephalitis (EEE) virus was found in a sample of mosquitoes collected last week in the village of Central Square.

Jiancheng Huang, Oswego County public health director, said he has requested the New York State Department of Health to issue a declaration of “imminent threat to public health” in Oswego County with the intent to conduct aerial spraying of the Big Bay and Toad Harbor Swamp area as soon as possible.

“The new evidence of Eastern equine encephalitis, together with the West Nile virus activity already present in Oswego County, drove the decision to spray,” said Huang. “Although the number of mosquitoes collected in trapping sites continues to be much lower than in prior years, considering virus activity in recent weeks, the weather forecast, and as a precautionary measure against a repeat of last year’s unusually rapid emergence of EEE, we need to conduct aerial spraying to control mosquitoes. We have started the process needed to conduct aerial spraying, and we will announce the schedule to the public as soon as it is developed.”

Huang emphasized that the decision on when and where to conduct aerial spraying is based on data collected in surveillance and mosquito control guidelines.

“West Nile and Eastern equine encephalitis are different diseases caused by different viruses and transmitted by different mosquito species,” said Huang. The risk of contracting either virus runs from June through September, with peak activity late July to mid-August.

The Oswego County Health Department collects samples of mosquitoes throughout the summer to look for evidence of West Nile and Eastern equine encephalitis viruses. EEE is usually detected in bird-biting mosquitoes before it appears in mammal-biting mosquitoes. In Central Square, the virus was found in the type of mosquito that bites birds, not in a species that feeds on humans. Aerial spraying may help reduce the risk of EEE spreading to human-biting mosquitoes.

Samples of mosquitoes collected earlier this summer in New Haven, Central Square and West Monroe tested positive for West Nile virus. An Oswego child recovered earlier this summer from West Nile. West Nile virus activity is also present in Onondaga County and areas of western and southern New York State.

“Most people infected with the WNV do not show any indication of the disease,” Huang said. Those who develop minor symptoms may have fever, headache, stomach ache, body aches, joint pain, vomiting, diarrhea and occasionally a skin rash and swollen lymph glands. The person’s health usually improves after several days, but they may feel tired and weak for weeks.

EEE, which claimed the life of an Oswego County girl last summer, is much rarer and is more often fatal. In the last 12 years, New York State has reported 490 human cases and 37 fatalities from West Nile virus. There have been five reported human cases of EEE in the last 40 years in New York State; all of them were fatal.

EEE can affect humans, birds, horses and other mammals. Most people bitten by an infected mosquito will not develop any signs; however, of those who do, symptoms usually appear four to ten days later.

Signs of EEE infection begin with a sudden headache, high fever, chills and vomiting. The illness may then progress into disorientation, seizures, coma or inflammation of the brain (encephalitis). It causes death in most cases; however, some people will survive the infection and have mild to severe brain damage for life.

Children under age 15 and adults over age 50 are at greatest risk of contracting EEE.

The Oswego County Health Department plans to hire a contractor to apply a mosquito adulticide to approximately 10,000 acres in the Toad Harbor and Big Bay swamps north of Oneida Lake. The area is bordered by U.S. Route 11 in Central Square to the west, NYS Route 49 to the north, the village of Constantia to the east, and the shoreline of Oneida Lake to the south. Spraying will not take place over the waters of Oneida Lake.

Huang emphasized that aerial spraying is a temporary measure to attempt to reduce the spread of mosquito-borne viruses. The mosquito population typically rebounds about a week after spraying, but mosquito numbers will naturally decline as the weather becomes cooler.

“It is essential that people throughout Oswego County keep using insect repellents and continue to be proactive in protecting themselves and their families from mosquito bites,” said Huang. “In addition to insect repellents, effective actions people can take are to stay away from areas where mosquitoes concentrate and to limit outside activity between dusk and dawn when mosquitoes are most active. Everyone needs to keep using personal protection measures from mosquito bites, even after spraying.”

Other precautions include:

Wear shoes, socks, long pants with bottoms tucked into boots or socks, and a long sleeved shirt when outdoors for long periods of time and at dawn and dusk.
Use mosquito repellent over clothes.  Repellants containing DEET are the most effective, but should be used with caution and according to label instructions. Products containing picaridin and oil of lemon eucalyptus are also effective.
Repair or replace broken screens in doors and windows.

For more information, call the Oswego County Health Department at 315-349-3547 or 1-800-596-3200, ext.3547 between 8:30 a.m. and 4 p.m. or visit the New York State Department of Health Web site at:   or