Jamestown Canyon Virus

What is Jamestown Canyon virus?

Jamestown Canyon virus (JCV) is a rare but emerging disease found throughout the U.S. It spreads to people who are bitten by mosquitoes infected with the virus.

JCV often doesn’t cause symptoms. Some people may experience fever, fatigue or headache. Jamestown Canyon virus can also lead to severe illness and hospitalization. The best way to avoid infection is to prevent mosquito bites.

Why is it named Jamestown Canyon virus?

Jamestown Canyon virus was first discovered in mosquitoes in 1961 in Jamestown, Colorado.

What type of disease is Jamestown Canyon virus?

Jamestown Canyon virus is an arbovirus. This type of virus is spread to people by insects (arthropods) like mosquitoes and ticks. Lyme disease, which is spread through tick bites, is a bacterial infection and not an arbovirus.

Other arboviral illnesses include:

• Chikungunya.
• Dengue fever.
• La Crosse encephalitis.
• Powassan virus.
• Rocky Mountain spotted fever (RMSF).
• Snowshoe hare virus.
• West Nile virus.
• Zika virus.

Is Jamestown Canyon virus rare?

Jamestown Canyon virus is rare, though the Centers for Disease Control and Prevention (CDC) has noted an increase in reported cases.

• Between 2012 and 2021, the CDC received 267 reports of the virus, most often in Wisconsin and Minnesota.
• In 2021, 32 cases of Jamestown Canyon virus were reported.

Researchers believe the disease is underdiagnosed and underreported due to a lack of awareness and testing. Symptoms of Jamestown Canyon virus may also be mistaken for other, more common infections.

Who might get Jamestown Canyon virus?

Anyone who gets a bite from an infected mosquito can get Jamestown Canyon virus. Most infections occur during the warmer months of April through September. Reported cases have occurred mostly among men and those assigned male at birth (AMAB).

How do I get infected by Jamestown Canyon virus?

You get Jamestown Canyon virus after an infected mosquito bites you. It’s not contagious, which means JCV can’t be passed (transmitted) from one person to another.

What are the symptoms of Jamestown Canyon virus?

Most people with Jamestown Canyon virus don’t develop symptoms. Or you may experience flu-like symptoms a few days to two weeks after your mosquito bite.

Common symptoms include:

• Fever.
• Fatigue.
• Headache.

You may also have:

• Chills.
• Cough.
• Dizziness.
• Muscle aches.
• Nausea or vomiting.
• Runny or stuffy nose (congestion).
• Sore throat (pharyngitis).

People who have weak immune systems or who are older may be more likely to develop severe disease from Jamestown Canyon virus. About 50% of people infected with JCV are hospitalized.

Severe symptoms may include:

• Confusion.
• Difficulty speaking or moving.
• Loss of coordination.
• Seizure.
• Sensitivity to light (photophobia).
• Stiff neck.

Go to the nearest emergency room or call 911 (or your local emergency services number) immediately if you or a loved one has one or more of these symptoms. You may have a central nervous system infection (neuroinvasive disease), such as encephalitis or meningitis, requiring emergency treatment.

What causes Jamestown Canyon virus?

Here’s how Jamestown Canyon virus spreads:

1. Small germs (microbes) infect mammals like deer or bison to produce more copies of itself.
2. Mosquitoes feed on infected animals, most often white-tailed deer.
3. The mosquitoes then bite people.
4. Infected saliva from mosquitoes enters your blood, infecting you.

What are the risk factors for Jamestown Canyon virus?

Your risk of developing JCV is higher the more you’re exposed to mosquitoes. Infection is more likely if you spend a lot of time outdoors or don’t take preventive measures to protect yourself from bites.

You may also be more likely to attract certain species of mosquitoes if you:

• Are larger and produce more carbon dioxide (CO2) and lactic acid.
• Have a certain blood type (a 2004 study suggested type O for some mosquito species).
• Move around or fidget a lot when mosquitoes are active (which also produces more CO2 and lactic acid).
• Produce a particular odor, including perfume or smelly feet.
• Wear dark clothing.

How is Jamestown Canyon virus diagnosed?

To diagnose Jamestown Canyon virus, your healthcare provider first asks about your symptoms. Tell your provider about any recent activities, including travel.

Your provider typically recommends blood tests, including an antibody test (virus-specific immunoglobulin test, or IgM test) to rule out other conditions and confirm a diagnosis. Your immune system produces antibodies against disease. If the blood tests show that you have antibodies, that means you have the virus because your body is defending itself against it.

You may need additional tests to confirm a diagnosis. Jamestown Canyon virus can be hard to tell apart from other similar diseases. Your provider may recommend:

• Spinal tap (lumbar puncture).
• MRI (magnetic resonance imaging).
• Plaque reduction neutralization test (PRNT).
• Reverse transcription-polymerase chain reaction (RT-PCR) test.

What is the treatment for Jamestown Canyon virus?

In most cases, you have no symptoms and don’t need treatment. For mild symptoms, your healthcare provider may recommend:

• Fluids to prevent dehydration.
• Over-the-counter (OTC) pain relievers to ease headache and fever.
• Rest.

If you develop severe symptoms, you may need to be hospitalized to receive IV fluids, medication and monitoring. No specific treatment for Jamestown Canyon virus is available.

Can Jamestown Canyon virus be prevented?

You can prevent infection by avoiding mosquito bites. Take precautions while you’re outdoors and follow safety guidelines when you travel.

To ward off mosquitoes and prevent bites:

• Avoid traveling to areas with active infections.
• Install screens in windows and doors and repair any holes or tears.
• Stay inside at peak mosquito hours, usually dusk and dawn.
• Remove sources of standing water to reduce mosquito breeding habitats.

When you’re outdoors:

• Cover exposed skin with appropriate outdoor clothing, including long-sleeve shirts and pants.
• Sleep inside or under protective netting.
• Treat outdoor gear, including clothing and camping supplies, with the insecticide permethrin.
• Use Environmental Protection Agency (EPA)-registered insect repellent, which generally includes DEET or picaridin, on skin and clothing.

What are the long-term effects of Jamestown Canyon virus?

Many people with Jamestown Canyon virus don’t experience any symptoms or lasting effects. If you develop severe illness, the long-term outlook depends on your symptoms and treatment plan. Your healthcare team works with you to support your recovery and steer you back to good health as quickly as possible.

When should I seek care for Jamestown Canyon virus?

Call your provider if you develop any unusual symptoms or reactions to mosquito bites, even if they occur days or weeks later. Also see your care team if you experience health issues after traveling to a place with mosquito-borne disease. Prompt diagnosis can lead to more effective therapy.

A note from Cleveland Clinic

Lots of people get mosquito bites, especially in warm weather. But it can be concerning when they do more than just make you itch. Jamestown Canyon virus is a rare but potentially serious infection. To prevent this illness, and other more common mosquito-borne diseases, take precautions when you and your loved ones work and play outdoors. Preventive steps can help you stay safe and healthy, all year long.