Tick-Borne Encephalitis (TBE)

What is tick-borne encephalitis (TBE)?

Tick-borne encephalitis (TBE) is a viral illness spread by ticks. Most people have no symptoms or flu-like symptoms, but some develop neurological conditions that can cause severe complications, like weakness and paralysis. A vaccine is available for people at higher risk.

TBE virus exists in parts of Asia and Europe. There are three subtypes based on where they’re found: European, Far Eastern and Siberian. Ticks in the U.S. don’t carry the tick-borne encephalitis virus.

What are the symptoms of tick-borne encephalitis?

Symptoms of TBE can happen in two phases. Initial symptoms start within about a week of getting bitten by a tick. They include:

• Fever.
• Headache.
• Body aches.
• Fatigue.
• Nausea.
• Loss of appetite.

A few days to a week later — and sometimes, weeks after the initial symptoms get better — some people develop neurological symptoms, including:

• Fever.
• Vomiting.
• Sensitivity to light (photophobia).
• Confusion or altered mental state.
• Muscle weakness.
• Stiff neck.
• Facial paralysis.
• Seizures.

What causes TBE?

Tick-borne encephalitis is caused by a virus (TBEV, a member of the genus Flavirus and family Flaviridae). It has three subtypes:

• European. Ixodes ricinus (castor bean) ticks spread European TBE (also known as Western TBE) in parts of eastern, central and northern Europe. It’s most common in Estonia, Latvia and Lithuania.
• Far Eastern. Ixodes persulcatus (taiga) ticks spread Far Eastern TBE (also known as Russian spring-summer encephalitis) in parts of eastern Russia, China and Japan.
• Siberian. Ixodes persulcatus (taiga) ticks spread Siberian TBE in parts of Russia, including Siberia and the Urals region, and some parts of northeastern Europe.

How does TBE spread?

Tick-borne encephalitis virus spreads through the bite of infected ticks. The ticks that carry it live in forested areas in Europe and Asia. You can also get it from drinking unpasteurized milk and human milk (through breastfeeding/chestfeeding).

What are the complications of TBE?

The main complications of TBE are swelling of your brain (encephalitis) and the membrane around your brain and spinal cord (meningitis). These cause the second stage of TBE symptoms and can lead to permanent:

• Paralysis.
• Memory loss.
• Balance and coordination issues.
• Speech and language issues.

How is TBE diagnosed?

Healthcare providers consider your symptoms and recent travel history to diagnose TBE. For example, they may ask if you’re returning from a trip to Asia or Europe where TBEV-carrying ticks are common. You may need a blood test or lumbar puncture (spinal tap) to confirm a diagnosis.

Make sure to let your provider know if you’ve traveled or been to an area with ticks recently, even if you don’t remember being bitten.

How is TBE treated?

There’s no specific treatment for tick-borne encephalitis. Drinking plenty of fluids, resting and taking over-the-counter pain relievers might help your symptoms. If you’re severely ill, healthcare providers will monitor you in the hospital. Some people need mechanical ventilation to help them breathe.

Can TBE be prevented?

Getting vaccinated against tick-borne encephalitis is the best way to prevent infection. People at higher risk for infection, like those taking part in outdoor activities in areas with ticks that carry TBEV, are eligible for the vaccine.

You can also reduce your risk for tick bites by:

• Wearing long pants, socks and long-sleeved shirts when outside in areas where there could be ticks.
• Wearing bug repellent with DEET.
• Checking your body and your pets for ticks when you come in from outdoors. Have someone else check areas you can’t see, like your scalp, neck and back.
• Talking to your veterinarian about how to protect pets that go outdoors from ticks.
• Keeping your grass cut short.

Finally, don't drink unpasteurized milk or milk products (like ice cream or cheese), which can also carry TBEV.

What can I expect if I have TBE?

What you can expect if you have TBE might depend on the subtype you have. European and Siberian subtypes are less likely to lead to neurological complications compared to the Far Eastern subtype. But Siberian subtypes can sometimes cause long-lasting or chronic illness.

If you’ve been diagnosed with TBE, you could develop neurological symptoms as many as 20 days after your initial symptoms get better.

What’s the mortality rate of tick-borne encephalitis?

The mortality (death) rate of European and Siberian TBE is less than 3%. For Far Eastern TBE, it’s as high as 35%.

When should I see my healthcare provider?

Talk to a healthcare provider if you’ve been in an area where you could’ve been bitten by a tick and you develop flu-like symptoms. They can let you know how to take care of yourself at home and what serious symptoms to look out for.

When should I go to the ER?

Go to the emergency room if you have symptoms of severe illness, including:

• High fever (over 103 degrees Fahrenheit/40 degrees Celsius).
• Severe headache.
• Confusion or altered mental state.
• Difficulty breathing.
• Extreme weakness.
• Paralysis.
• Seizures.

What questions should I ask my doctor?

It might be helpful to ask your healthcare provider:

• How do I get vaccinated if I’m traveling somewhere that TBE spreads?
• How do I take care of myself at home?
• Am I at risk for severe symptoms?
• What symptoms should I look out for?

What’s the difference between TBE and Lyme disease?

TBE and Lyme disease are both spread by ticks, but they’re different illnesses. A virus causes TBE and there are no specific treatments for it. Bacteria cause Lyme disease and it’s treatable with antibiotics. Lyme disease spreads in some of the same areas that TBE does in Europe and Asia, but ticks don’t spread TBE in the U.S.