Levy County Mosquito Control

Independent Vector Information & Public Health Network

Home > Epidemiology & Tracking > Eastern Equine Encephalitis

Eastern Equine Encephalitis (EEE) Alerts

Eastern Equine Encephalitis (EEE) is one of the most severe mosquito-borne diseases in North America. While human cases are relatively rare, the mortality rate is exceptionally high. Because Levy County features a dense concentration of both freshwater hardwood swamps (the primary vector habitat) and equestrian agriculture, EEE represents a unique and persistent threat to our rural communities.

Critical Alert for Equine Owners

EEE is exceptionally lethal to horses, carrying a mortality rate of 70% to 90% in unvaccinated animals. Death usually occurs within 2 to 4 days of the onset of neurological symptoms (circling, head pressing, wandering, and seizures).

There is a highly effective vaccine available for horses, but there is NO vaccine for humans. The LCMN Advisory Board strongly urges all farm owners in the Williston and Bronson areas to maintain strict, up-to-date bi-annual equine vaccination schedules.

The Swamp Vector

The primary maintenance vector for EEE is the Culiseta melanura mosquito. Unlike mosquitoes that breed in backyard containers or urban drains, this species breeds almost exclusively in the hidden, water-filled crypts of hardwood swamps (such as the base of uprooted cypress or tupelo trees).

This mosquito primarily bites birds. However, when infected birds leave the swamp, “bridge vectors” (like Aedes or Coquillettidia mosquitoes) bite the infected bird and subsequently transmit the virus to mammals.

Human Risk & Symptoms

In humans, EEE has an incubation period of 4 to 10 days. The disease presents in two forms: systemic or encephalitic.

Encephalitic Infection: Symptoms include sudden high fever, chills, severe muscle pain, and rapid progression into disorientation, seizures, or coma.

Mortality: The human mortality rate for the encephalitic form is roughly 30%. Of those who recover, over half are left with permanent, severe neurological impairment.

Sentinel Tracking & Prevention

The LCMN utilizes Sentinel Chicken Flocks placed near Levy County’s major swamp borders to detect the presence of EEE before it bridges into human or equine populations. Because the primary vector lives deep in inaccessible swamps, traditional neighborhood chemical fogging is highly ineffective at stopping the root source of EEE.

Rural residents must rely on personal and architectural protection:

  • Avoid outdoor activities near wooded areas or swamps during peak biting times (dusk and dawn).
  • Utilize EPA-registered repellents containing DEET, Picaridin, or IR3535 when working outdoors.
  • Report sudden avian die-offs (especially crows or blue jays) immediately, as birds succumb rapidly to the virus.
Access the Dead Bird Reporting Portal

Levy County Mosquito Control Information Network

Dedicated to Public Health & Environmental Stewardship in the Gulf Coast Region.

Public Information Desk: 352-486-5127