Symptoms, Diagnosis, and Treatment


Many people infected with Powassan virus do not have symptoms. For people with symptoms, the time from tick bite to feeling sick ranges from 1 week to 1 month.

  • Initial symptoms can include fever, headache, vomiting, and weakness.
  • Powassan virus can cause severe disease, including infection of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis).
    • Symptoms of severe disease include confusion, loss of coordination, difficulty speaking, and seizures.
    • Approximately 1 out of 10 people with severe disease die.
    • Approximately half of the people who survive severe disease have long-term health problems such as recurring headaches, loss of muscle mass and strength, and memory problems.


If you think you or a family member might have Powassan virus disease, talk to your healthcare provider.

  • Healthcare providers diagnose Powassan virus infection based on:
    • Signs and symptoms
    • History of living in or traveling to an area where Powassan virus is known to circulate
    • History of possible exposure to the ticks that can carry Powassan virus
    • Laboratory testing of blood or spinal fluid
  • Your healthcare provider can order tests to look for Powassan virus infection or other infections that can cause similar symptoms.

To learn more about testing, visit our Healthcare Providers page.


  • There are no medications to prevent or treat Powassan virus infection. Antibiotics do not treat viruses.
  • Rest, fluids, and over-the-counter pain medications may relieve some symptoms.
  • People with severe disease often need to be hospitalized to receive support for breathing, staying hydrated, or reducing swelling in the brain.

To learn more about treatment, visit our Healthcare Provider page.