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Mosquito Control

  • Eastern equine encephalitis virus is a member of the family Togaviridae, genus Alphavirus.
  • Closely related to Western equine encephalitis virus and Venezuelan equine encephalitis virus
  • Many persons infected with EEEV have no apparent illness. In those persons who do develop illness, symptoms range from mild flu-like illness to EEE (inflammation of the brain), coma and death.
  • The mortality rate from EEE is approximately one-third, making it one of the most deadly mosquito-borne diseases in the United States.
  • There is no specific treatment for EEE; optimal medical care includes hospitalization and supportive care (for example, expert nursing care, respiratory support, prevention of secondary bacterial infections, and physical therapy, depending on the situation).
  • Approximately half of those persons who survive EEE will have mild to severe permanent neurologic damage.
  • Approximately 220 confirmed cases in the US 1964-2004
  • Average of 5 cases/year, with a range from 0-15 cases
  • States with largest number of cases are Florida, Georgia, Massachusetts, and New Jersey.
  • EEEV transmission is most common in and around freshwater hardwood swamps in the Atlantic and Gulf Coast states and the Great Lakes region.
  • Human cases occur relatively infrequently, largely because the primary transmission cycle takes place in and around swampy areas where human populations tend to be limited.
  • Residents of and visitors to endemic areas (areas with an established presence of the virus)
  • People who engage in outdoor work and recreational activities in endemic areas
  • Persons over age 50 and younger than age 15 seem to be at greatest risk for developing severe EEE when infected with the virus.
  • A vaccine is available to protect equines.
  • People should avoid mosquito bites by employing personal and household protection measures, such as using an EPA-registered repellent according to manufacturers’ instructions, wearing protective clothing, avoiding outdoor activity when mosquitoes are active (some bridge vectors of EEEV are aggressive day-biters), and removing standing water that can provide mosquito breeding sites. For more information about preventing mosquito-borne disease see Preventing West Nile Virus.
  • The cornerstone of laboratory diagnosis of EEEV infection is serology, especially IgM testing of serum and cerebrospinal fluid (CSF), and neutralizing antibody testing of acute- and convalescent-phase serum.
  • In fatal cases, however, PCR, histopathology with immunohistochemistry, and virus culture of autopsy tissues continue to be useful. Only a few state laboratories or other specialized laboratories, including those at CDC, are capable of doing this specialized testing.

EEEV infection is thought to confer life-long immunity against reinfection with EEEV. It does not confer any significant cross-immunity against other alphaviruses (e.g., Western equine encephalitis virus), and it confers no cross-immunity against flaviviruses (e.g., West Nile virus) or bunyaviruses (e.g., La Crosse virus)

  • Human EEE cases are reportable by state health departments to CDC via ArboNET. Reports of infected horses, mosquitoes, and birds are also collected by ArboNET
  • National human EEE case report data for 1964-2004 are posted on this website, by state, as is a map of reported human cases from 1964-2004

Risk of exposure to EEEV-infected mosquitoes may increase as the human population expands into natural areas where the virus circulates (e.g., near hardwood, freshwater swamps in the eastern and north-central United States).

  • No human EEEV vaccine is currently licensed and it is unlikely that one will be available in the foreseeable future.
  • No specific drug treatment for EEE is available.
  • Control measures for EEEV are challenging and expensive. For example, laws for the protection of wetlands limit efforts to eliminate some swamps or to treat them with mosquito larvicides or aerial insecticides; in some regions, there is a lack of public support for use of insecticides to reduce populations of mosquitoes that transmit EEEV or other mosquito-borne viruses.
*** WEST NILE VIRUS ALERT ***
  • West Nile virus is spread by the bite of an infected mosquito, and can infect people, horses, many types of birds, and some other animals.
  • Most people who become infected with West Nile Virus will have either no symptoms or only mild ones.
  • On rare occasions, West Nile virus infection can result in a severe and sometimes fatal illness known as West Nile encephalitis (an inflammation of the brain).   The risk of severe disease is higher for those with compromised or weak immune systems, young children and persons 50 years of age and older.
HOW TO RID YOUR YARD OF HIDDEN MOSQUITOES

Get rid of stagnant water.  Mosquitoes live and breed in places with lots of standing water—and they don’t fly very far.  So check your home and yard for places where water can collect, including:

–         Gutters:  They can easily become clogged with leaves and debris

–         Birdbaths:  Drain and refill your birdbaths once a week

–         Flower pots:  Look for water in the platters underneath the pots

–         Swimming pools and hot tubs:  Drain any unused pools, and drain the water     off the covers regularly

–         Wading pools:  Drain them, and turn them over when not in use

–         Look for and discard any other potentially wet places where mosquitoes can congregate, such as old tires, tin cans, and empty pots.

Avoid the outdoors during high-risk times.  Mosquitoes that carry West Nile Virus are most active at dawn, dusk, and early evening.

Keep mosquitoes outside.  Make sure that all of the windows and doors in your home have tight-fitting screens.  Repair or replace those screens that are torn or have holes.

Do not rely on ultrasonic devices, backyard bug zappers, or bird/bat houses in the backyard to rid your home and yard of mosquitoes.
5. Obstructions in culverts, blocking the flow of water through the drainage ditch.