What is TBE?

Tick-borne encephalitis (TBE) is a viral disease that affects the central nervous system. As the name suggests, this infection occurs when an infected tick, mostly found in wooded areas, bites someone.

TBE Phases

The disease presents itself  often in two phases. The first phase is milder, with symptoms such as:

• fever
• headache
• fatigue
• nausea
• muscular aches

The first phase of TBE can feel similar to the flu, and its symptoms can last an average of 5 days. Following this phase is often a time with no symptoms that usually lasts 7 days, although it can range anywhere from 1 to 33 days.

Things become more serious with the second phase as the disease affects the neurological system. The disease may presents itself in the following two ways: meningitis and/or encephalitis.

Meningitis is an inflammation of the membrane surrounding the spinal cord and brain, and encephalitis is an inflammation of the brain itself. Both of these conditions can be very dangerous.

TBE Subtypes

There are three subtypes of TBE: European, Far Eastern, and Siberian.

The European subtype is transmitted by the Ixodes ricinus ticks. It is native to the rural and forested areas of eastern, central, and northern Europe. This subtype often presents as a milder disease, with only 20-30% of those infected entering the second phase.

The far eastern subtype is transmitted primarily by the Ixodes persulcatus tick. It is found in far-eastern Russia and forested regions of Japan and China. This subtype typically presents the most severe diseases, with a mortality rate of up to 35%.

Finally, the Siberian subtype is also transmitted by the Ixodes persulcatus tick, but it is primarily located in the Urals region, far-eastern Russia, and Siberia. It can also be found in some areas in north-eastern Europe. This is a less severe subtype, but patients tend to develop chronic or significantly prolonged infections.

TBE Treatment

Unfortunately, there is no antiviral treatment specific for TBE, and treatment instead focuses on supportive management. If it progresses to meningitis, meningomyelitis, or encephalitis, hospitalization is required where supportive care can then be managed based on syndrome severity.

What is Lyme Disease?

Other then the viral TBE, Lyme disease, otherwise known as Lyme borreliosis, a bacterial infection, transmitted by ticks. In most cases, Lyme disease is caused by the bacterium Borrelia burgdorferi, although in rare cases, the Borrelia mayonii bacteria can be its the source too. These bacteria are transmitted when bitten by an infected Ixodes ricinus tick.

Lyme Disease Symptoms

The symptoms of Lyme disease include:

• headache
• fatigue
• fever
• erythema migrans (a skin rash)

The skin rash of erythema migrans is the easiest way to detect Lyme disease. It is usually a circular red area that often clears in the middle, creating a bullseye. However, only around one of three people with Lyme disease will develop this rash, so it is not the only sign to look for to recognize Lyme disease.

Lyme Disease Treatment

If Lyme disease is left untreated, it can spread to the heart, joints, and also the nervous system, causing symptoms such as pain in the joints, numbness, memory or heart problems. However, most cases of Lyme disease can be successfully treated with a few weeks of antibiotics. Additionally, the sooner Lyme disease is diagnosed, the easier it is to treat.

Comparing TBE and Lyme Disease

Both of these diseases result from a tick bite, so how can you distinguish between the two?

Initially, both of these infections show similar flu-like symptoms. One in three people with Lyme disease will additionally develop the erythema migrans rash, which is an easy way to distinguish between these two infections.

If you feel sick after spending time in a wooded area or you were bit by a tick, it is best to visit a doctor to determine if an infection may have occured. Lyme disease has antibiotic treatment options, and while TBE does not have a specific antiviral therapy, supportive care is still available, especially for those who enter its second phase.

Protecting Yourself from TBE and Lyme Disease

For both tick-borne illnesses, the best form of prevention is through protection. If you are traveling somewhere that is wooded or at risk of tick-borne diseases, be sure to alter your habits to protect yourself.

There is no vaccine for Lyme disease, but a TBE vaccine is available in some areas at high risk of disease transmission. In Switzerland the vaccination is recommended for all citizens in most cantons, especially for those taking part in outdoor activities near forested areas such as camping, hiking, fishing, hunting, or birdwatching. Ticks are also more active during the warmer months, so if you plan on traveling during this time, it may be wise to inquire about the vaccine.

Other methods of disease prevention involve general ways of preventing tick bites, including wearing long clothing and using insect repellant. When in the woods, it is also best to avoid areas with high grass and leaf litter, and it is best to remain in the center of trails.

Uniquely Swiss

Reports have shown increasing cases of tick-borne disease in Switzerland, with cases of both Lyme disease and TBE rising. In Switzerland, tick season extends from March to November, and ticks can be found in all forests with lush undergrowth at altitudes up to 1,500m.

As with most tick-borne diseases, the exposure peaks in young adults and then declines with increasing age. This makes sense because ticks reside in wooded areas, and young adults are more likely to go hiking for fun.

However, there is a phenomenon that is uniquely Swiss when it comes to tick-borne diseases. Because tick-borne diseases are typically contracted through outdoor activities such as hiking, it is unusual for those in higher age groups, such as those over the age of 90, to become infected. In Switzerland, though, many older and retired individuals spend their time hiking, which then exposes them. This is why the risk of tick-borne diseases extends to later in life in Switzerland than in most other places in the world, and why proper protection at all ages is important.

References

1. Factsheet about tick-borne encephalitis (TBE). (2022). https://www.ecdc.europa.eu/en/tick-borne-encephalitis/facts/factsheet
2. Lyme Disease. (2022). https://www.cdc.gov/lyme/index.html