What Is Powassan Virus? This Tick-borne Illness Can Cause Fatal Swelling of the Brain
The disease is still very rare, but about 10% of people who get it die.
When you think about ticks and the illnesses they can carry, you probably think of Lyme disease—for good reason. Lyme disease is certainly the most common and widespread tick-borne illness, and it’s been reported in all 50 states.
But it’s not the only one: In recent years, scientists have been warning about another, less common but very dangerous disease carried by these tiny bugs. It’s called the Powassan virus, and it takes just minutes to be transmitted from tick to human. Here’s everything you need to know about this new threat to outdoor summer safety.
What is the Powassan virus?
Like Lyme disease, Powassan virus is contracted through the bite of an infected tick, says Alan Taege, MD, an infectious disease specialist at Cleveland Clinic. But unlike Lyme disease, a tick doesn’t have to be attached for 24 to 48 hours to transmit the Powassan virus; animal studies suggest that humans can become infected in just 15 minutes.
“This is a rare, uncommon condition that we are only beginning to learn about and understand,” says Dr. Taege. According to the CDC, the first two cases of the Powassan virus in the United States were reported in 2008. Since then, the number of US annual cases of Powassan virus have ranged from 2 to 33.
Powassan virus has been predominantly found in the northeastern and north central United States. According to the CDC’s Powassan virus map, the largest number of cases have been reported in Minnesota, Wisconsin, and New York.
Powassan virus symptoms
Symptoms of the Powassan virus can vary: Some people infected with the virus will experience no effects at all, while others can become seriously ill or even die.
According to the CDC, the incubation period for Powassan virus—the time from tick bite to onset of illness—ranges from about 1 week to 1 month. Symptoms can begin anytime after this point.
The Powassan virus can impact the central nervous system, and can cause encephalitis (inflammation of the brain) and meningitis (inflammation of the membranes that surround the brain and spinal cord). It can also cause symptoms such as fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties, and seizures.
Of those who contract the Powassan virus, 50% will have permanent symptoms, such as recurrent headaches, muscle wasting, and memory problems. The Powassan virus can also be fatal: About 10% of cases result in death.
Treatment for Powassan virus
“If your doctor suspects you have the Powassan virus, the diagnosis is made by these symptoms and blood tests,” says Dr. Taege. Unfortunately, there is no specific treatment; only supportive care. There is currently no vaccine for it, either.
People who are diagnosed with Powassan disease and have severe symptoms will likely need to be hospitalized, according to the CDC. They may receive breathing support, IV fluids, and drugs to reduce swelling around their brain and spinal cord.
If you are being treated for another tick-borne illness, you may also want to be checked for the Powassan virus. “Ticks can be multiply infected, so if a tick is infected with Lyme (or another virus), it could also be infected with the Powassan virus,” Sorana Segal-Maurer, MD, director of the Dr. James J. Rahal Jr. Division of Infectious Diseases at NewYork-Presbyterian Queens, tells Health.
How to prevent Powassan virus
When it comes to prevention, reducing exposure to ticks is the best defense. “The goal is to not get bitten,” says Dr. Segal-Maurer. “Wear long pants, with socks pulled up over them, long sleeves, and light colors so you can see if ticks are on your clothing. Common places ticks may be include ankles or the back of knees.”
You should also apply insect repellent when you’ll be spending time in tick-infested areas. “Always use DEET,” says Dr. Segal-Maurer. People get nervous about DEET, but the benefits can outweigh the risk.”
Always perform a tick check on yourself and your pets when you get back inside after spending time outdoors in areas where ticks are prevalent. If you discover a tick that’s attached to your skin, remove it with fine-tipped tweezers and call your doctor for advice on what to do next.
To get our top stories delivered to your inbox, sign up for the Healthy Living newsletter