The virus is transmitted via deer ticks. Noel Hendrickson/Getty Images
  • Powassan virus is carried by deer ticks and can be transmitted to humans through tick bites.
  • While Powassan virus disease is rare, a few cases have made headlines in recent weeks.
  • Most people who contract the virus don’t have symptoms, but in rare cases, it can cause encephalitis and meningitis.

Headlines were made recently about two Connecticut residents with Powassan virus disease. While coronavirus has been making headlines for over a year, you may be wondering what exactly the lesser-known Powassan virus is and if there is reason to panic.

Experts say you probably don’t need to be concerned.

And you definitely don’t need to spend your summer indoors. Powassan virus can cause an extremely rare deer tick-borne infection that, for the most part, does not cause serious harm. 

However, in rare cases, the virus can cause encephalitis (an infection of the brain) or meningitis (infection of the membranes around the brain and spinal cord). In the last 10 years, there have been fewer than 200 cases of neuroinvasive disease from the Powassan virus.

Still, it’s best to avoid contracting the virus if you can. Here’s what you need to know.

What is the Powassan virus?

Powassan virus is carried by deer ticks and can be transmitted to humans when they’re bitten by these ticks. While the disease caused by the virus is rare, the number of cases has gone up in recent years. Most people who contract the virus are unaffected, but in rare cases, it can cause encephalitis and meningitis.

How is it different from Lyme disease?

Powassan virus and Lyme disease are both carried by deer ticks, but the comparison stops there.

“Powassan virus is a virus as the name implies. Lyme disease is [caused by] bacteria,” said Dr. David Goldberg, an infectious disease specialist at New York-Presbyterian. “They are completely different organisms. The [other] main difference is that Powassan is extremely rare.”

Lyme disease is much more prevalent. According to the CDC, there were 23,453 confirmed cases of Lyme disease in 2019 alone, compared to the fewer than 200 cases of Powassan virus disease in the last decade.

Since Lyme disease is a bacterial infection, there are antibiotic options to treat it. There is currently no way to treat Powassan virus disease and there is no vaccine.

Where and when is Powassan virus most prevalent?

The majority of Powassan virus cases are found in the parts of the country where deer are most abundant. This includes the Northeast and the Great Lakes regions, typically from spring through fall. 

What are the symptoms of Powassan virus disease?

The incubation period for Powassan virus can range from 1 week to 1 month. Those who show symptoms may feel:

  • fever
  • headache
  • vomiting
  • weakness

In extreme cases where people develop encephalitis or meningitis, symptoms can include:

  • confusion
  • loss of coordination
  • difficulty speaking
  • seizures 

“Sometimes post-encephalitis, people can have lingering neurologic symptoms, which can be variable. Some can be memory loss, persistent confusion, loss of balance, hearing loss,” said Dr. Nima Majlesi, director of medical toxicology at Staten Island University Hospital. 

“If someone has signs of encephalitis and it is the right time of year and in the right part of the country, you can test the blood and spinal fluid for evidence of the virus, but really, there is no other way to tell. There probably are many more cases that we don’t know about that are milder,” said Goldberg.

If you see a tick embedded in your skin and you are unsure how long it’s been there, or you are unable to fully remove it yourself, call a healthcare professional to see what they recommend.

Who is at risk for Powassan virus disease?

Anyone who has been exposed to a tick bite in the parts of the country where Powassan virus occurs is at risk.

If your job or daily life has you outside in wooded areas often, you may be at a higher risk. There is no demographic that is more at risk than others.

How can I avoid Powassan virus?

Don’t worry — there is no need to stay inside this summer. You can practice the same precautionary measures that you do with all tick bites to prevent exposure to Powassan virus. 

“Prevention is about surveillance,” said Majlesi. “There are a lot of ways to prevent tick bites. It’s multi-factorial.” Some prevention measures include:

  • wearing long pants in wooded areas
  • spraying your body or clothes with permethrin
  • showering immediately after being outdoors
  • doing a full body check after coming in from outdoors

One of the most important things to remember is that Powassan virus disease is very rare. So while it is always good to be cautious and take preventive measures, it does not mean that you need to spend your summer inside.

“Avoid the over-fear,” said Majlesi. “We’re talking about a disease that is extremely rare. If you take these preventive measures, you have a very low likelihood [of contracting the virus]. Enjoy yourself. Be outside, be active, and be educated.”

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