Tick-borne encephalitis is a viral infection spread primarily through tick bites. Most people have no symptoms, but some people develop flu-like symptoms or more severe disease.

Tick-borne encephalitis (TBE) is a virus that’s transmitted by bites from an infected tick. Rarely, it can also be spread through the consumption of raw milk.

Although most people don’t experience symptoms, some people may develop serious disease of their central nervous system.

TBE is found in parts of Europe and Asia, but not in the United States. Vaccination is recommended for people living in or visiting those regions.

Read on to learn more about TBE, including symptoms, risk factors, prevention, treatment, and the outlook for people with this infection.

TBE is a viral infection involving the central nervous system. People usually contract the virus when they’re bitten by an infected tick in woodland habitats.

About 70%–75% of people infected with TBE don’t develop any symptoms. In people who experience symptoms, the illness typically develops in two phases.

Common initial symptoms

The first phase involves flu-like symptoms that occur after an incubation period of 2–28 days. Flu-like symptoms can include:

  • headache
  • fatigue
  • fever
  • aches and pains
  • weakness
  • vomiting

More severe symptoms

Several days later, up to 30%–50% of people may develop more serious symptoms involving the central nervous system. This can include inflammation of the brain (encephalitis) or the tissues surrounding the brain and spinal cord (meningitis).

Serious symptoms can include:

  • stiff neck
  • severe headache
  • sensitivity to lights or sounds
  • drowsiness
  • altered mental status
  • confusion
  • slurred speech
  • seizures
  • tremors
  • loss of movement in part of the body

If you experience any of these symptoms, speak with a doctor or call your local emergency number right away. These symptoms can indicate serious disease that requires immediate medical attention.

TBE is found in many parts of Europe and Asia, including:

  • Western, Northern, and Eastern Europe
  • United Kingdom
  • Northern and Eastern Asia
  • Russia
  • China
  • Japan

The risk of contracting TBE is higher during warmer months, from April through November, when ticks are most active.

Ticks live in grassy, brushy, and wooded areas. People spending time outdoors in or near forests have a higher risk of being bitten by a tick infected with the virus.

Outdoor activities that increase the risk for TBE include:

  • hiking
  • camping
  • hunting
  • fishing
  • farming
  • forestry work

Also, many people encounter ticks in their own yard or neighborhood when gardening or hiking.

People of any age can contract TBE, but it’s more common in adults than in children.

In rare cases, people can get TBE by consuming raw (unpasteurized) milk or dairy products from animals infected with the virus, such as goats, sheep, and cows.

Is there tick-borne encephalitis in the United States?

No, TBE isn’t found in the United States.

But, people traveling from the United States to Europe or Asia may be at risk of TBE infection, especially from April through November.

If you’re planning to travel to these regions, speak with a doctor about getting the TBE vaccine. Vaccination is the best way to prevent TBE infection.

There are many effective ways you can reduce your risk of TBE.

The best way to protect yourself is to get the TBE vaccine. The Centers for Disease Control and Prevention (CDC) recommends the vaccine for anyone living in or traveling to areas where TBE occurs, especially if they’re planning outdoor activities.

Have a conversation with a doctor to learn more about the TBE vaccine if you’re planning to travel to high-risk regions in Europe or Asia. You’ll need to get the vaccine at least 1 month before traveling.

If you spend time outdoors in regions where TBE occurs, be sure to:

  • Avoid wooded and brushy areas with tall grass, including in your own yard or neighborhood.
  • Walk in the center of clearly marked trails.
  • Wear protective clothing, such as long-sleeve pants and closed footwear.
  • Use insect repellents containing DEET, picaridin, oil of lemon eucalyptus, or para-menthane-diol.

After being outdoors, make sure to:

  • Check your clothing and entire body for ticks.
  • Remove any ticks as soon as possible, using tweezers or a tick removal tool.
  • Examine pets as well as hiking or camping gear, such as backpacks, coats, and tents.
  • Take a shower within 2 hours of returning indoors.

It’s also important to eat only pasteurized milk and dairy products. This will ensure you avoid the rare chance of infection from unpasteurized products.

There’s no effective antiviral treatment for TBE infection. Therapy involves supportive care to manage symptoms and complications.

People experiencing flu-like symptoms may find relief by:

  • getting plenty of rest
  • drinking fluids and staying hydrated
  • taking over-the-counter (OTC) pain and cold medications

People who develop serious infection involving the central nervous system often require treatment in a hospital.

Treatments for people with severe encephalitis can include:

  • pain relief medication to reduce discomfort or fever
  • medication to reduce inflammation
  • medication to manage seizures or fits
  • fluids given by intravenous (IV) injection to prevent dehydration
  • oxygen to support breathing

Treatments for people with severe meningitis can include:

  • pain relief medication for severe headaches
  • medication and rehydration therapy to relieve nausea and vomiting

Most people with TBE will recover. But, up to one-third of people with TBE may experience long-term complications.

Long-term complications

Long-term complications can include:

  • cognitive disorders
  • memory and concentration disorders
  • vision, balance, and coordination disorders
  • hearing loss or tinnitus
  • paralysis

Long-term outlook

The long-term outlook for people with TBE depends on the subtype of TBE infection. According to research, the case-fatality rate (which is the proportion of people who die from a disease among all people with the disease) across subtypes is:

  • European subtype: less than 2%
  • Siberian subtype: 2%–3%
  • Far Eastern subtype: 20%–40%

The risk of incomplete recovery is higher for people with more severe disease during the initial phase of TBE. Also, research suggests adults older than 60 have a higher risk of more severe disease.

TBE is a viral infection primarily transmitted by ticks in wooded or brushy areas throughout Europe and Asia.

Vaccination is the best way to prevent infection if you’re planning outdoor activities in high-risk areas. Other effective strategies include avoiding high-risk areas, using insect repellant, and checking your body for ticks immediately after being outdoors.

Speak with a doctor about TBE vaccination if you plan to travel to high-risk areas.