Officials from the Maine Department of Health and Services and the Maine Department of Agriculture Animal Health and Industry Division confirmed that five horses have died from Eastern equine encephalitis, and three more suspected cases are pending test results.
Veterinarians confirmed two EEE related deaths in Cumberland County and Waldo County last week. In July, two horses in Waldo County and one in Penobscot County died from the virus according to www.thehorse.com.
EEE, a viral disease originating in birds and transmitted by mosquitoes, causes illness in humans, horses and some bird species.
State Veterinarian Don Hoenig, DVM, noted that an annual vaccine can prevent most EEE cases. He said, “All horse owners should be sure their horses are current on their EEE vaccination, as this is a very effective vaccine.”
“In all confirmed positive cases thus far, the horses were not up to date on their EEE vaccine or had a questionable vaccination history,” he continued.
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EEE has a mortality rate approaching 100 percent in horses, making it one of the most serious mosquito-borne diseases. A lack of effective treatment causes most equine deaths within 48-72 hours of the first symptoms, which include unsteadiness, erratic behavior and a marked loss of coordination.
Humans infected with EEE often display no symptoms, or slight flu like symptoms within three to 10 days of an infected bite. There is no human vaccine, and the fatality rate is about one third of infected persons.
“These five dead horses with EEE indicate that there is a risk of people contracting the infection from mosquito bites,” said Mills, MD, MPH, and director of the Maine CDC. “Until we experience several deep frosts, it is important people take precautions to avoid getting bitten by mosquitoes.”
EEE rarely infects humans because the transmission cycle occurs in freshwater swamps and wetlands where human populations are low. Horses are not capable of transmitting the disease to humans or other horses.
