Jamestown Canyon Virus Fact SheetRevised February, 2014
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What is Jamestown Canyon virus?
- Jamestown Canyon virus is an illness that is transmitted to people through the bite of an infected mosquito. The virus is a Bunyavirus within the California serogroup and is closely related to La Crosse encephalitis virus.
How serious is Jamestown Canyon virus?
- Symptoms may include:
- flu-like illness
- Severe cases involving the Central Nervous System (CNS) may include meningitis (inflammation of the membranes surrounding the brain) or encephalitis (inflammation of the brain).
- Treatment for Jamestown Canyon virus involves supportive care until the illness resolves.
Who is at risk for Jamestown Canyon virus?
- Persons at risk of disease include those exposed to infected mosquitoes. Jamestown Canyon virus is an illness that is rarely reported in Minnesota. Two cases have been reported in Minnesota residents since 2002 with single cases occurring in 2002 and 2013. Cases of Jamestown Canyon virus occur throughout the United States but are only reported sporadically. Since national reporting began in 2004, only a few cases have been reported to the Centers for Disease Control and Prevention (CDC) each year. Under-diagnosis and under-reporting of disease are likely as diagnostic testing for JCV is not widely available.
What kind of mosquito transmits Jamestown Canyon virus?
- In Minnesota we have approximately 50 species of mosquitoes but not all of these mosquitoes feed on human blood. Several species of mosquitoes are able to transmit Jamestown Canyon virus, including many that commonly bite people. Cases of human disease may occur anytime during the warmer months of Minnesota with the highest risk of disease from May through early September.
What can people do to prevent Jamestown Canyon virus?
- Avoid mosquito bites:
- Avoid outdoor activities at dusk and dawn, the peak feeding time for many mosquitoes.
- Wear long-sleeved shirts and long pants (light-colored clothing works best).
- Use repellents containing DEET according to label directions – less than 30% DEET is sufficient for adults and children. Other effective repellents include picaridin, IR3535, and oil of lemon eucalyptus.
- Remove standing water from your property:
- Remove or turn over any containers that could hold water (toys, cans, flower pot saucers, etc.) Check your property in the spring before plants have the chance to grow and hide these objects from you.
- Change the water in bird baths at least once a week to prevent mosquito breeding.
- Recycle old tires or store them where they can’t collect rainwater. If these aren’t options for you then cover them with a tight tarp or store them in direct sunlight.
- Check gutters and clean out leaves frequently to make sure they aren’t plugged.
- Fill water-holding tree holes with dirt or sand to prevent further mosquito breeding.