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
  • 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
  • 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
  • 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.

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.