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September 3, 2021
PO Box 330
Trenton, New Jersey 08625-0330

Jeff Wolfe
P: (609) 913-6559
C: (609) 433-1785


Second and Third Eastern Equine Encephalitis Cases for New Jersey in 2021

(TRENTON) – An 8-year-old mare and 7-year-old miniature horse stallion in Atlantic County are the second and third reported 2021 cases of Eastern Equine Encephalitis (EEE), a serious mosquito-borne illness in horses, in New Jersey.  The horses had not been vaccinated against EEE and both were humanely euthanized due to severity of the disease. One other EEE case was previously identified this year in Cumberland County.

“These new cases of Eastern Equine Encephalitis emphasize the importance of horse owners needing to vaccinate their animals to greatly reduce the chances of contracting EEE and West Nile Virus,” New Jersey Secretary of Agriculture Douglas H. Fisher said.  

EEE causes inflammation of the brain tissue and has a significantly higher risk of death in horses than West Nile Virus (WNV), a serious viral disease that affects a horse’s neurological system.  The diseases are transmitted by a mosquito bite.  The virus cycles between birds and mosquitoes with horses and humans being incidental hosts.  EEE infections in horses are not a significant risk factor for human infection because horses (like humans) are "dead-end" hosts for the virus.

For more information about EEE in horses, visit the New Jersey Department of Agriculture web site at:

In general, most regions in New Jersey have a reported mosquito population at or slightly above the 5-year averages ( The first EEE positive mosquito pool was detected in Gloucester County this year ( Livestock owners are strongly encouraged to vaccinate against WNV, EEE and other mosquito-borne diseases. Effective equine vaccines for EEE and WNV are available commercially.  Horse owners should contact their veterinarians to see if their horses are up to date on their vaccinations against both EEE and WNV. Reported WNV cases in New Jersey this year have been limited to wild avian species, three Cooper's hawks and one American crow.

EEE and WNV, like other viral diseases affecting a horse’s neurological system, must be reported to the state veterinarian at 609-671-6400 within 48 hours of diagnosis. The New Jersey Animal Health Diagnostic Laboratory is available to assist with EEE and WNV testing and can be reached at 609-406-6999 or via email at Learn more about the NJ Animal Health Diagnostic lab at


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