Symptoms, Diagnosis, and Treatment

Symptoms

• 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.

Diagnosis

• Healthcare providers diagnose Powassan virus infection based on:
  • Signs and symptoms
  • History of possible exposure to the ticks that can carry Powassan virus
  • Laboratory testing of blood or spinal fluid
• More information on diagnostic testing is available here.

Treatment

• There is no medication to treat Powassan virus infection.
• People with severe disease often need to be hospitalized to receive support for breathing, staying hydrated, or reducing swelling in the brain.
• If you think you or a family member might have Powassan virus disease, see your healthcare provider.
• To learn more about treatment, visit our Healthcare Provider page.