Woman in Wisconsin dies of rare, mosquito-borne brain infection. Here's what you need to know

WHEELING, IL - JUNE 20:  Lab assistant Amy Sebo drops mosquitoes into test tubes as she prepares them to be tested with the VecTest procedure for West Nile Virus, Saint Louis Encephalitis, Eastern Equine Encephalitis and Antigen Panel Assay June 20, 2003 at the Northwest Mosquito Abatement District headquarters in Wheeling, Illinois. Illinois reported 884 cases and 64 deaths from the West Nile Virus last year, the highest amount in the nation. (Photo by Tim Boyle/Getty Images)
Wisconsin health officials are warning about the dangers of a rare, mosquito-borne illness called eastern equine encephalitis (EEE) after a woman in her 60s died of the infection. (Tim Boyle/Getty Images)

Health officials in Wisconsin are warning about the dangers of a rare, mosquito-borne illness called eastern equine encephalitis (EEE) after a local woman died of the infection.

The woman, who has not been publicly identified, was in her 60s, according to the Wisconsin Department of Health Services (DHS). “This is the second confirmed case of EEE in our state this year, and the seriousness of this infection cannot be overstated,” interim State Health Officer Stephanie Smiley warned in a news release. “Since mosquitoes continue to be active in Wisconsin, we are urging people to continue to take steps to protect themselves from mosquito bites.”

There have also been nine cases of EEE in horses in Wisconsin this year, according to the DHS. “These cases in animals and now in two residents of our community represent unusually high levels of EEE activity in the state,” the release said.

EEE isn’t an infection most people are familiar with, and it’s understandable to have questions about it. Here’s what you need to know, plus why doctors say you shouldn’t panic.

What is EEE?

The EEE virus is a rare cause of a brain infection called encephalitis, according to the Centers for Disease Control and Prevention. The EEE virus can cause a systemic illness (meaning it can affect the entire body) or a neurological disease that can lead to meningitis, an infection of the membranes that surround the brain and spinal cord, or encephalitis, an infection of the brain, the CDC says. Some people may experience the systemic form before the encephalitic form.

About 30 percent of people who contract EEE die, often within 10 days of developing symptoms, the CDC says. Many of those who survive suffer from brain dysfunction.

What are the symptoms of EEE?

The symptoms of the EEE virus vary depending on the form the infection takes. The CDC lists the following as symptoms of a systemic infection: fever, chills, malaise, joint pain and muscle pain.

Symptoms of the neurologic disease, meanwhile, may include fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness or coma.

How common is it?

EEE cases are not common in the U.S., where typically 11 or fewer instances occur in people each year, according to data from the CDC. However, there were 38 infections documented by the CDC last year. “It’s a rare infection,” Dr. Richard Watkins, an infectious disease specialist in Akron, Ohio, and a professor of internal medicine at Northeast Ohio Medical University, tells Yahoo Life.

According to the CDC, five cases of the disease have been reported in 2020 so far.

How do people get infected with EEE?

The EEE virus is maintained in a cycle between birds and mosquitoes that typically bite them, the CDC explains. However, when select mosquito species — such as Aedes, Coquillettidia or Culex — are infected, they can also infect humans and horses, both considered “dead-end” hosts for the virus. That’s because the concentration of it in their bloodstreams is usually not sufficient enough to keep the cycle going and infect mosquitoes, the CDC says. Horses are also not thought to be a risk factor for spreading the infection to humans, the CDC says.

While EEE isn’t common anywhere in the U.S., cases have been reported most often in Massachusetts, Florida and Wisconsin, with a smattering in other states, largely on the East Coast.

How is EEE treated?

While there is a vaccine for EEE in horses, there is none for humans, the CDC says. There also is no antiviral treatment for EEE. “Supportive care can help you through it, but we really can’t do anything to alter the progression of the disease,” Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life. “It’s all in prevention.”

Prevention involves using insect repellent that is registered with the Environmental Protection Agency (EPA), wearing long-sleeved shirts and pants, and taking steps to control mosquitoes around your home, including keeping windows and doors closed and using air-conditioning, if possible, the CDC says. “Policing your area is important,” Schaffner says. “Go around your dwelling and look for any standing water, including in small objects. Birdbaths and toys, if they get water in them, can be breeding grounds for mosquitoes.”

How worried about this should people be?

If you live in an area that has recently seen a case of EEE, Schaffner recommends paying attention to the guidelines issued by local health authorities. But the general public, he says, should simply be aware that EEE exists and do their best to prevent mosquito bites. “Don’t panic,” he stresses. “The risk is very, very low.”

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