Florida: 2nd Eastern Equine Encephalitis case reported in Holmes County, 14th case in horse in 2024
The Florida Department of Agriculture and Consumer Services (FDACS) reported an additional Eastern Equine Encephalitis (EEE) in a horse in Holmes County in Florida’s Panhandle.
According to officials, the animal was an unvaccinated 4-year-old Gypsy Vanner stallion from a private facility in the county who presented with symptoms of apprehension, depression, elevated temperature, incoordination, weakness in hind limbs and an inability to stand on June 19.
The stallion was euthanized.
This is the second EEE case reported in Holmes County and the 14th case in Florida in the first six months of 2024- Holmes (2), Marion (2), Osceola (2), and one each in Alachua, Columbia, Duval, Highlands, Jackson, Levy, Polk and Suwannee counties.
To date in Florida, positive samples have been reported from 31 sentinel chickens, 14 horses, two emus, and one emu flock from 20 counties.
Eastern Equine Encephalitis is a viral disease that causes inflammation of the brain and spinal cord. It is transmitted by mosquitoes.
In North America, Eastern Equine Encephalitis virus (EEEV) is normally maintained in wild bird populations. Culiseta melanura, a mosquito that preferentially feeds on birds, is the most important vector in this sylvatic cycle (the portion of a pathogen's natural transmission cycle that involves wild animals and insects). Other, mosquito species that feed on both birds and mammals (“bridge vectors”) may transmit EEEV to humans and domesticated mammals.
It causes disease in equids (horses, mules, burros, donkeys and zebras) and humans in the North America.
EEE has been detected in eastern Canada, all U.S. states east of the Mississippi, and some additional states such as Arkansas, Minnesota, South Dakota and Texas.
A number of other animals such as pigs, llamas, bats, reptiles, amphibians, and rodents can also be infected. Birds are reservoirs for the virus, often being infected without signs of disease. Some birds (e.g., pheasants, emus, whooping cranes, partridges) can have illness or death once infected with EEE or other equine encephalitis viruses (Western Equine Encephalitis and Venezuelan Equine Encephalitis).
Clinical signs and symptoms of EEE include the following: Depression and anorexia; initially without a fever when initially infected, Moderate to high fever, Lack of appetite, Lethargy/drowsiness and Neurologic signs— onset of neurologic disease is frequently sudden and progressive
Periods of hyperexcitability, apprehension and/or drowsiness
Fine tremors and fasciculations of the face and neck muscles
Convulsions
Cranial nerve paralysis-facial paralysis and weakness of the tongue are very common
Head tilt, droopy lip, muzzle deviation
Weakness, ataxia, and incoordination
Complete paralysis of one or more limbs
Colic
Recumbency
Death—EEE is a life-threatening disease in equids, with a case fatality rate as high as 90% in horses with encephalitis. Many surviving animals have severe residual neurological signs.
Diagnosis is made by a veterinarian by measuring titers in serum (a component of whole blood) using an ELISA (enzyme-linked immunosorbent assay) or, less commonly, with PCR or CSF (cerebrospinal fluid).
There is no cure for Eastern Equine Encephalitis. Supportive care is administered in horses which show clinical signs.
Vaccination for EEE is highly effective and is recommended as a core vaccination.
In humans, EEE is rare with only a few cases are reported in the United States each year. Most cases occur in eastern or Gulf Coast states.
While rare, eastern equine encephalitis is very serious. Approximately 30% of people with eastern equine encephalitis die, and many survivors have ongoing neurologic problems. Symptoms of eastern equine encephalitis can include fever, headache, vomiting, diarrhea, seizures, behavioral changes, and drowsiness.
There are no vaccines to prevent or medicines to treat eastern equine encephalitis.
You can reduce your risk of infection with eastern equine encephalitis virus by preventing mosquito bites.