Powassan Virus

Powassan virus is a rare tick-borne viral infection. You can get it when an infected tick bites you. The ticks that can spread the virus are blacklegged (deer) ticks, groundhog ticks and squirrel ticks. Infections occur most often in the northeastern and Great Lakes regions of the U.S. Powassan is uncommon, but reported cases are on the rise.

If a tick bites you, it’s important to remove it as quickly as possible. That’s because ticks can transmit Powassan as soon as 15 minutes after they bite. Most people infected with the virus have mild or no symptoms. But sometimes, the virus can infect your brain or the tissues around it. This can lead to life-threatening complications, like brain swelling. In some cases, it can be fatal.

There’s no cure or specific treatment for Powassan virus. People with mild illness usually recover with supportive care at home. If you have a severe case, you need immediate treatment at a hospital.

Powassan virus symptoms

Many people with Powassan virus don’t develop symptoms. If you do get symptoms, they usually start one week to one month after an infected tick bites you. This is called the incubation period.

Initial symptoms of Powassan can include:

• Fever
• Headache
• Nausea and vomiting
• Extreme weakness

If the virus progresses, it can infect your brain and central nervous system. This can lead to severe complications, including:

• Encephalitis (inflammation of the brain)
• Meningitis (inflammation of the membranes surrounding the brain and spinal cord)

Severe Powassan symptoms can include:

• Confusion
• Seizures
• Difficulty speaking
• Loss of coordination

Powassan virus causes

Powassan virus is a flavivirus. This is an RNA virus that usually spreads through mosquitoes and ticks. You get Powassan virus from the bite of an infected Ixodes tick. There are three types:

• Ixodes scapularis (blacklegged or deer tick)
• Ixodes cookei (groundhog tick)
• Ixodes marxi (squirrel tick)

Blacklegged (deer) ticks are most likely to spread the virus to humans. Squirrel ticks rarely bite people.

Powassan virus doesn’t spread from person to person. You can only get it from the bite of an infected tick.

Risk factors

Powassan virus can affect anyone, but some people are at a higher risk, including:

• Adults age 65 and older
• Infants and children
• People with weakened immune systems
• People who spend time outdoors in wooded or brushy areas

How doctors diagnose this condition

A healthcare provider may suspect you have Powassan virus disease if you:

• Have symptoms of the condition
• Live in or have traveled to an area where Powassan virus spreads
• Could have been bitten by a tick (even if you don’t remember being bitten)

Your provider might do certain tests to help diagnose Powassan virus, including:

• Blood tests
• Spinal tap (lumbar puncture)
• Imaging tests, like CT scans or MRI

Powassan virus treatment

There aren’t any specific antiviral medications or vaccines for Powassan virus. Treatment involves supportive care, including:

• Managing symptoms with over-the-counter (OTC) medications
• Rehydrating with fluids
• Watching you closely for complications

If you’re severely ill, your provider might treat you in the hospital with:

• Antiseizure medication to manage seizures
• Supplemental oxygen or mechanical ventilation to help you breathe
• Intravenous (IV) fluids to keep you hydrated
• Corticosteroids to reduce swelling
• Tube feeding if you’re unable to feed yourself

When should I see my healthcare provider?

See a provider if:

• A tick has bitten you. There’s no treatment to prevent Powassan virus. But your provider can tell you if you need treatment for other tick-borne illnesses.
• You’ve been in an area with ticks and have symptoms of Powassan virus. Even if you don’t remember being bitten, it’s important to seek care.

When should I go to the emergency room?

Go to the nearest ER if you have signs of serious illness, including:

• Confusion or other mental changes
• Seizures
• Trouble speaking
• Paralysis

What questions should I ask my healthcare provider?

It might be helpful to ask your provider:

• How do I take care of myself at home?
• What new or worsening symptoms should I look out for?
• How soon should I feel better?
• When should I follow up with you?

What can I expect if I have Powassan virus?

Most mild symptoms of Powassan virus disease get better with at-home treatment.

But if you have encephalitis or another serious complication, your provider will need to monitor your condition in the hospital. You might need treatments or procedures to help you breathe or to reduce swelling.

Life expectancy

If Powassan virus infects your brain or spinal cord, it’s fatal about 10% of the time.

About half of the people with severe illness who survive experience long-lasting health effects. These can include:

• Memory problems
• Ongoing headaches
• Muscle weakness
• Trouble with balance or coordination

Can Powassan virus be prevented?

Avoiding tick bites is the best way to reduce your risk of Powassan virus. Ways to protect yourself from ticks include:

• Cutting your grass shorter than 5 inches
• Staying on clear paths if you’re in the woods
• Applying U.S. Environmental Protection Agency (EPA)-approved repellents that contain DEET or other ingredients that keep ticks away
• Covering up your skin as much as possible with light-colored clothing, long sleeves and pants
• Checking your body, clothing and pets for ticks after you’ve been outside
• Showering within two hours after coming indoors
• Asking a veterinarian the best way to protect your pets from ticks

Powassan virus can spread faster than other infections, like Lyme disease. So, removing a tick quickly is important. To safely remove a tick, use fine-tipped tweezers to grab its head. Then, gently pull it away from your skin with even, steady pressure.