Its high-pitched whine gives it away — that mosquito hovering near your ear. It’s maddening, that buzz. It portends of a future bite, one that will swell and itch. And although the chances are very slim in Maine, that mosquito could transmit a deadly virus.
“It’s still not common in our state at all, but we always tell people to make sure they protect themselves from mosquitoes,” James Dill, a pest management specialist with the University of Maine Cooperative Extension, said. “Now they’re much more than a nuisance, unfortunately.”
In recent years, two mosquito-borne illnesses have been reported in Maine: West Nile virus and Eastern equine encephalitis, which is commonly known as EEE.
To date, Maine has reported two residents with confirmed West Nile virus, one in 2012 and one in 2015, and two residents have contracted EEE, one in 2014 and one in 2015, according to the Maine Center for Disease Control and Prevention. One of the cases was fatal.
Know the risk
EEE is rare but deadly. In fact, because of the high mortality rate, it’s considered to be one of the most serious mosquito-borne illnesses in the country. From 2004-2013, an average of eight human cases of EEE were reported annually throughout the U.S., according to data collected by the CDC. In 40 percent of those cases, the disease was fatal.
Occurring in the eastern half of the U.S., EEE causes illness in humans, horses and some bird species. Many people infected with EEE will have no obvious symptoms, according to the CDC, but those who do develop illness experience a range of symptoms, including high fever, sore neck, headache, lack of energy and inflammation of the brain, which can lead to coma or death.
West Nile virus, which occurs throughout the U.S., is more common than EEE. Last year, 2,060 human cases of West Nile virus were reported nationwide, and about 6 percent of the cases were fatal, resulting in 119 deaths.
The majority of people infected with West Nile virus don’t show any symptoms. A mild West Nile virus infection can cause fever, headache and body aches, often with a skin rash and swollen lymph glands. In serious cases, the virus can manifest into neck stiffness, stupor, disorientation, coma, tremors, convulsions, paralysis and death, according to the CDC.
There are no vaccines for EEE or West Nile virus, and there is no specific treatment for either illness, according to the CDC.
Both illnesses are “best prevented by avoiding exposure to mosquitoes,” according to the Maine Division of Infectious Disease, which provides a wealth of information on mosquito-borne illnesses through the state website, maine.gov.
Mosquito season in Maine stretches from June to October, in theory, but these noisy pests can pop up during other times of the year. Overwintering female mosquitoes can appear during the spring, fall and occasionally during the winter, according to a fact sheet on mosquitos provided online by the University of Maine Cooperative Extension pest management office.
In Maine, there’s no escaping mosquitoes entirely. But there are plenty of ways to repel and evade them.
One method to avoid being bitten is simply covering your skin with thick clothing — for example, wearing pants instead of shorts. Or you can wear bug netting, which may be a more comfortable option for a hot summer day. Bug-net hats, jackets and pants are sold at outfitters throughout Maine.
Usually people who are planning to spend time outdoors during the summer in Maine will use insect repellent of some sort. There are many varieties on the market. Some insect repellent contains chemicals such as DEET, while others are made of entirely natural ingredients and must be applied more often in order to remain effective. Be sure to read the instructions for any insect repellent you purchase before use.
Also, beware of “novelty approaches to mosquito control,” such as bug zappers and noise makers, the University of Maine Cooperative of Extension warns. Some of these products are expensive and have little scientific evidence to support that they’re effective in repelling mosquitoes.
“If it sounds too good to be true, it probably is,” Dill said.
At home or camp, people often burn wicks containing pyrethrum or citronella candles to repel mosquitoes. These tools may provide some relief in limited areas, provided there’s no wind, according to the UMaine Cooperative Extension.
It’s also important to keep mosquitoes from sneaking indoors by installing and maintaining tight-fitting window and door screens and keeping outdoor lighting to a minimum. You can also treat screens and tents with certain pesticides, such as permethrin.
Maine is home to roughly 40 species of mosquitos, and less than half of those species bite humans. The other species opt to bite other types of animals, such as birds and reptiles.
Here’s another neat fact: Only female mosquitoes bite, and they’re capable of biting more than once. Mosquitoes — males and females — feed on nectar for sustenance, but females need the iron and protein in blood to produce eggs, according to the Prairie Research Institute.
Mosquitoes breed in standing water, while black flies — Maine’s other notorious pest — breed in flowing water.
“It doesn’t take much water. A couple tablespoons of water can grow some mosquitoes,” Dill said. “The best thing you can do — we tell people all the time — is to make sure you disrupt any standing water. Make sure your gutters aren’t clogged up, that the bucket sitting beside your shed isn’t full of rain water.”
Bird baths are other hot spots for mosquito breeding. To prevent this, simply rinse out your bird bathes once per week, Dill said.
Also, spread the word to your neighbors, he added. If you’re the only one in your neighborhood eliminating mosquito breeding areas, it won’t make much of a difference.
A new threat
Earlier this year, the World Health Organization declared a Public Health Emergency of International Concern because of the mosquito-borne Zika virus, which typically causes a mild illness including fever, rash, joint pain and conjunctivitis, but if contracted during pregnancy it can cause a serious birth defect called microcephaly, as well as other severe fetal brain defects.
Zika isn’t new. Since the 1950s, outbreaks of Zika have been reported in Africa, Southeast Asia and the Pacific Islands. But now, it appears to be spreading, according to the CDC.
In May 2015, the first case of Zika virus infection was confirmed in Brazil. Since then, local transmission has been reported in several other countries and territories, including Puerto Rico, the U.S. Virgin Islands and American Samoa.
“Everyone is concerned about the Zika virus and the mosquito’s transmission of it,” Dill said. “Right at the moment, two species [of mosquitoes] are known to be vectors of the virus, and we do not have either one of them established in Maine.”
So far, no locally transmitted Zika cases have been reported in the continental United States, but 618 cases have been reported in returning travelers, according to the CDC. Earlier this month, the CDC confirmed the first case of a baby being born with Zika-related birth defects in the continental United States, according to a June 2 Washington Post story.
“We don’t believe it’s here [in Maine], but it never hurts to look,” Dill said. “You never know what’s moving northward and where you’ll find it.”
To learn more about protecting yourself from mosquitoes and mosquito-borne illnesses, visit the Maine Division of Infectious Disease website at maine.gov/dhhs/mecdc/infectious-disease/epi/vector-borne/.