Health officials in Central Florida are advising the public to take extra precautions against mosquitoes after a potentially deadly mosquito-borne virus was detected.
Several sentinel chickens recently tested positive for the Eastern equine encephalitis virus (EEEV), which can cause brain infections and swelling, the Florida Department of Health in Orange County announced Thursday.
“The risk of transmission to humans has increased,” the department said. “DOH-Orange and mosquito control agencies will continue surveillance and prevention efforts.”
Orange County includes the cities of Orlando, Lake Buena Vista and Apopka.
EEEV is quite rare, with only three cases reported so far this year and just six last year. This is primarily because the virus is usually transmitted in and around swampy areas that are sparsely populated, according to the U.S. Centers for Disease Control and Prevention.
About a third of all people who contract EEEV die, however, and many of those who survive it are left with disabling and progressive mental and physical conditions. This can range from minimal brain dysfunction to severe intellectual impairment, personality disorders, seizures, paralysis and cranial nerve dysfunction, the CDC’s website states.
Its symptoms include fever, headache, irritability, restlessness, drowsiness, anorexia, vomiting, diarrhea, cyanosis, convulsions and coma.
Out of precaution, sentinel chickens are placed in areas where disease outbreaks can begin and are regularly tested for the virus ― as well as other mosquito-borne viruses like West Nile ― to alert health officials about its potential spread. This is because a species of mosquito that’s known for initiating the virus’ cycle of transmission, called Culiseta melanura, feeds almost exclusively on birds like chickens, the CDC’s website explains.
This mosquito species infects its avian hosts with the virus. After this, other mosquito species that are capable of transmitting the virus between birds and mammals ― including the Aedes, Coquillettidia, and Culex species ― will then carry it from infected avian hosts to uninfected mammals, such as humans and horses.
Unlike humans, the chickens don’t get sick from the diseases, according to the website American Veterinarian and Australia’s University of Melbourne, where sentinel chickens are similarly used.
Health officials advise using insect repellent and wearing long-sleeved shirts and long pants to prevent mosquito bites. They also encourage draining standing water, which can collect in things like flower pots, saucers, bottles, tires, buckets and roof gutters, to remove environments where the insects breed.
“As little as one teaspoon or bottle cap of water standing for more than one week is enough for mosquitoes to breed and multiply,” Florida’s DOH-Orange warns in an infographic shared on Twitter.