ELKHART — A new warning about the threat of mosquito-borne illnesses reflects a seasonal spike in such cases in humans and horses alike, health officials say.
The Elkhart County Health Department on Friday reissued a warning from earlier this year regarding the threat of mosquito-borne illnesses, which can be dangerous, even fatal, for both humans and horses.
West Nile virus has been found in numerous locations throughout Elkhart County, as has Eastern equine encephalitis.
Occurrences of West Nile Virus tend to be higher in early fall as well, while EEE increases in occurrence in the late summer.
“The disease is in birds normally. Later in the summer and early fall, they’ve had more time to get it,” said Carrie Brunson, environmental supervisor for the Elkhart County Health Department.
EEE, also known as “sleeping sickness,” is a zoonotic alphavirus and arbovirus with the capability of causing rare brain infections. Only a few cases are reported in the United States each year, but for those who contract it, the virus can be deadly.
The incubation period for Eastern equine encephalitis virus disease ranges from four to 10 days. There may or may not be symptoms.
“In humans, most people are asymptomatic,” Brunson said. “Most people don’t even know they have it.”
Those who wind up with systemic EEE find themselves with an abrupt onset of chills, fever, malaise, arthralgia and myalgia lasting for a week to two weeks.
Encephalitic patients also have swelling of the brain, with signs such as fever, headache, irritability, restlessness, drowsiness, anorexia, vomiting, diarrhea, cyanosis, convulsions and even coma, according to the Centers for Disease Control.
Approximately a third of humans who are exposed to EEE will die from the disease within two to 10 days following symptom onset. Those who do recover may be left with disabling and progressive mental and physical sequelae. Many patients with severe sequelae die within a few years and others suffer from personality disorders, learning impairments, seizures, paralysis and cranial nerve dysfunction.
So far, Michigan has experienced three human cases and six equine cases, officials said. Two deer were also believed to have contracted EEE.
While West Nile is a concern every year, so far only about 2.6 percent of the tested populations have tested positive, compared to over 5 percent in years past. Meanwhile, EEE is seeing the most activity since 2012, when there were eight cases, and equine deaths have already been reported in Southern Michigan, although the causes are yet unproven.
“It’s 90 percent deadly to horses,” Brunson said.
Luckily for horses and their owners, yearly vaccinations prevent the illness from spreading. All equine deaths have occurred only to unvaccinated horses.
Barbara O’Day, owner of former Danbar Farm Inc., Elkhart, is one of many horse owners in the area who use vaccines to keep their animals safe.
“They’ve had a lot of it in Southern Michigan since I moved here 37 years ago,” she said. “They had a lot of it down there (Florida) and I worked for a vet, so I’ve always known that if you immunize against it, you’ll keep their strength up.”
While not every species of mosquito can harbor life-threatening diseases, humans should protect themselves against all forms of mosquitoes to be safe, such as wearing repellent containing DEET when outside during the day and at night, especially while in the woods.
“It’s kind of a myth that mosquitoes only bite at night, especially if you’re in the woods or in the shade,” Brunson said.
Wearing long sleeves and long pants will also help to avoid mosquito bites, as will ensuring household screens and doors are properly attached and free from holes. Make sure grass and overgrown vegetation are cut down, gutters are unclogged and containers holding water remain empty.
“I think we get complacent this time of year, but we need to be aware,” Brunson said. “Mosquitoes are the deadliest animals on the planet.”