State Health Department Working with Central New York Counties on Controlling Disease-Carrying Mosquitoes

ALBANY, N.Y. (August 16, 2011)  – Following a fatality caused by Eastern Equine Encephalitis (EEE) in Oswego County earlier this week, the New York State Department of Health (DOH) today outlined its multi-faceted program to control EEE and steps it is taking to address this mosquito-borne disease.

Although mosquitoes carrying disease can be found across the state, the highest risk areas for EEE are the Central New York counties of Onondaga, Oneida, Madison and Oswego located around Oneida Lake.

DOH has conducted a comprehensive program to study, understand and control EEE in Central New York for several decades. While personal protective measures remain a critical step to prevent EEE infection, DOH provides consultation to county health departments on control measures which can include methods to reduce mosquito larvae in the spring.

DOH also provides consultation on spraying pesticides to reduce adult mosquito populations. While spraying has been shown to reduce adult mosquito populations for about one week in the area sprayed, spraying does not eliminate the risk of EEE infection. In fact, last year, an EEE case occurred in an area that had been sprayed several weeks before.

The decision to undertake adult mosquito control measures is a local decision, while the state DOH can provide technical assistance and data to assist in targeting efforts. The decision to spray is influenced by a variety of complex factors including, surveillance data, mosquitoes population numbers and species of mosquito populations, the density and proximity of human populations, the time of year, weather conditions, and others.

Other components of the Department's comprehensive program include.

  • Mosquito surveillance: Working with the four county health departments, starting in early summer, DOH coordinates the weekly collection and identification of mosquitoes from traps located in key habitats for EEE. A DOH staff entomologist located in Central New York assists the county health departments in collecting and analyzing these data. Key information gathered includes the size of mosquito populations and the presence of sub-populations of bird-biting and mammal-biting species of mosquitoes that directly relate to the risk of EEE infection to people.
  • Mosquito testing: The DOH Wadsworth Laboratory tests these mosquitoes for EEE virus on a weekly basis. The information on EEE infection in the subpopulations of mammal-biting species of mosquitoes is key information in determining the risk of EEE infection to people.
  • Surveillance for horse (equine) illness: DOH and the four counties maintain surveillance of veterinarians for encephalitis in horses. Horses are very sensitive to EEE and infection is often fatal. Suspect cases are tested at the DOH Wadsworth Laboratory to confirm infection.
  • Surveillance for human illness: Encephalitis is a reportable condition in New York. Each summer, DOH send alerts to physicians to be aware of the symptoms of EEE, West Nile Virus and other forms of infectious encephalitis. Suspect cases are tested at the DOH Wadsworth Laboratory for a host of potential causes.

Personal protective measures that the Department recommends include:

  • When outdoors by using an effective mosquito repellent and wearing long pants and long sleeves. DOH and the federal Centers for Disease Control and Prevention (CDC) recommend applying insect repellent containing DEET, picaridin, or oil of lemon eucalyptus.
  • Insect repellants containing oil of lemon eucalyptus should not be used on children under 3, and products containing DEET should not be used on infants under two months. For children older than 2 months, the American Academy of Pediatrics recommends products containing 10 percent to 30 percent DEET. Ten percent DEET provides protection for about 2 hours and 30 percent protects for about 5 hours. Choose the lowest concentration that will provide the required length of coverage. It is important to always follow the label directions when using insect repellent.
  • When indoors, New Yorkers are advised to keep doors closed and ensure that window screens are in place to prevent mosquitoes from entering homes.

People are also advised to take steps to reduce the number of mosquitoes around a home or property, eliminate standing water in yards, and make sure all windows and doors have screens that are in good repair. In addition, New Yorkers are urged to:

  • Dispose of used tires, tin cans, plastic containers, ceramic pots or similar containers in which water collects.
  • Drill holes in the bottoms of recycling containers that are kept outdoors. Make sure roof gutters drain properly and clean clogged gutters in the spring and fall.
  • Turn over plastic wading pools and wheelbarrows when not in use, and change the water in bird baths twice a week.
  • Clean vegetation and debris from the edges of ponds. Clean and chlorinate swimming pools, outdoor saunas and hot tubs.
  • Drain water from pool covers.

More information on Eastern Equine Encephalitis is available at: