Symptoms, Diagnosis, & Treatment


Many people infected with Jamestown Canyon virus do not have symptoms. For people with symptoms, the time from mosquito bite to feeling sick (incubation period) ranges from a few days to 2 weeks.

  • Initial symptoms can include fever, fatigue, and headache.
    • Some people also have respiratory symptoms such as cough, sore throat, or runny nose.
  • Jamestown Canyon 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 can include stiff neck, confusion, loss of coordination, difficulty speaking, or seizures.
    • About half of patients reported with Jamestown Canyon virus disease are hospitalized.
    • Deaths associated with Jamestown Canyon virus infection are rare.


If you think you or a family member might be infected with Jamestown Canyon virus, talk with your healthcare provider.

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

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


  • There are no specific medicines to prevent or treat Jamestown Canyon virus infection. Antibiotics do not treat viruses.
  • Rest, fluids, and over-the-counter pain medications may relieve some symptoms.
  • In severe cases, patients may need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.

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