West Nile is not the only mosquito-born virus that poses a threat to Maryland and the Atlantic states—the Eastern Equine Encephalitis (EEE) that killed a Massachusetts woman during the the weekend has been posing a rare but serious threat to the region for years.
The difficulty is predicting where and when there will be an outbreak. But when it does strike, the fatality rate is deadlier than West Nile. Around 30 percent of people who get encephalitis from mosquitoes carrying the EEE virus die, compared to West Nile victims who have a less than 5 percent fatality rate, according to Dr. Diane Griffin with Johns Hopkins Bloomberg School of Public Health.
There have been 147 fatalities out of the 3,545 cases of West Nile virus reported in the United States this year as of Sept. 25, according to the latest statistics from the Centers for Disease Control and Prevention (CDC), Reuters reports in the Huffington Post.
But with Triple E, the percentage is higher, "EEE is one of the most severe mosquito-transmitted diseases in the United States with approximately 33% mortality and significant brain damage in most survivors," according to the CDC.
It's a more virulent virus, Griffin said.
“Summer may be over but the threat of mosquito-borne illness is not — we can expect to continue seeing mosquito activity until the first hard overnight frost,” said Dr. Al DeMaria, state epidemiologist for Massachusetts, where seven cases of EEE have been reported and two deaths, Mansfield Patch reported.
For those who live, problems can persist. Some survivors experience paralysis and seizures, and some children are left with mental retardation, according to Griffin. Even some who appear to recover—report memory loss or trouble sleeping, she added.
Despite the perils posed by EEE, an outbreak in Massachusetts does not indicate there will be an outbreak in Maryland, according to Griffin.
Still the death in Massachusetts from Triple E is is not a rarity for an Atlantic state, according to Griffin.
Triple E is endemic all along the East Coast, Great Lakes and Gulf Coast, but mainly in mosquitoes and birds, she said. Unlike the mosquitoes that carry West Nile, the species that carry EEE are pickier and prefer birds, according to Griffin.
"Some mosquitoes are really picky, others aren't," she said. "The ones that carry West Nile will feed on many different vertebrates, basically both birds and mammals."
Problems arise for people when the mosquitoes that aren't picky get infected with Triple E. Periodically it gets into the populations of mosquitoes that do feed on people; when this happens, EEE usually appears in horses before people, according to Griffin. Thus the equine in its name.
The rhyme or reason behind when it strikes people is not a simple puzzle. But high concentrations of mosquitoes are never a good sign, according to Griffin.
The virus is always around but there are very few cases, according to Griffin. "Nevertheless avoiding mosquito bites is a good thing," she said.
Just as with West Nile, the only protection available is protection against mosquito bites, according to Griffin. "Keep the mosquitoes away from you," she said.
The state monitors the mosquito population and when it looks like there might be a problem they usually spray, she said. They're spraying now for mosquitoes around Baltimore because of West Nile virus, she reported Tuesday.
Mosquitoes carrying West Nile or Triple E are more commonly out in morning and evening, she said and recommended people protect themselves from being bitten by using insect repellent or wearing long sleeves.