TBE (Tick-Borne-Encephalitis)Tick-borne encephalitis (TBE) is an important cause of viral infections of the central nervous system. The vast majority of infections with the virus result from infected ticks, which often remain firmly attached to the skin for days. (source)
- The TBE virus is transmitted to humans through the bite of an infected tick.(1,2) TBE can also be acquired by ingesting unpasteurized dairy products (such as milk and cheese) from infected goats, sheep, or cows.(1,2) Direct person-to-person spread of TBE virus occurs only rarely.(1,2)
- A safe and effective vaccine against the TBE virus exists and is recommended for people who live or work in, or travel to TBE risk areas.(3)
- Austria is a high-risk area for TBE. No region is free of TBE and therefore a vaccination is recommend to all Austrian citizens.(5,6)
- Most cases occur from April to November, with peaks in early and late summer when ticks are active.(2)
- Immunization offers the most effective protection against TBE and furthermore the risk of tick-borne infections is reduced by avoiding tick bites.(3)
- There is no specific antiviral treatment for TBE.(2) Most patients with TBE encephalitis will recover but up to one third will suffer long-term complications of the disease.(3)
What is TBE?
- TBE is an infectious disease caused by the TBE virus.(1,2) It is mainly transmitted through the bite of an infected tick.(1,2) In addition, the virus can also be transmitted by the consumption of raw milk products (e.g. goat or sheep milk).(1,2)
- Transmission from person to person only occurs very rarely, through blood transfusion, solid organ transplantation, or breastfeeding.(1,2)
- Ticks live on the ground and climb 20-70 cm onto grasses and bushes where they wait for hosts. The tick bite is painless and it is often impossible to sense a tick moving on the skin.(3)
- Ticks can also transmit the Lyme disease.(2) While TBE is caused by a virus, Lyme disease is caused by bacteria and cannot be prevented by the TBE vaccination.(2,6)
Where does TBE occur?
- TBE is endemic to focal areas of Europe and Asia, extending from eastern France to northern Japan and from northern Russia to Albania.(2)
- Approximately 5,000–13,000 TBE cases are reported each year, with large annual fluctuations.(2)
- Russia has the largest number of reported cases.(2)
The highest disease incidence has been reported from western Siberia, Slovenia, and the Baltic States (Estonia, Latvia, Lithuania).(2)
- Austria is a high-risk area for TBE.(6) No region is free of TBE.(6)
Who is at risk of contracting TBE?
- Most TBE virus infections result from tick bites acquired in forested areas through activities such as camping, hiking, fishing, bicycling, collecting mushrooms, berries, or flowers, and outdoor occupations such as forestry or military training.(2)
- In disease endemic areas, people with recreational or occupational exposure to rural or outdoor settings (e.g., hunters, campers, forest workers, farmers) are potentially at risk for infection by contact with the infected ticks.(1) Furthermore, as tourism expands, travel to areas of endemicity broadens the definition of who is at risk for TBE infection.(1)
What are the symptoms and lasting effects of TBE?
The incubation period of TBE is usually between 7 and 14 days and is asymptomatic.(1) Symptoms during the first phase of clinical TBE are nonspecific and may include fever, malaise, anorexia, muscle aches, headache, nausea, and/or vomiting.(1) After about 8 days of remission, a second phase of disease occurs in 20% to 30% of patients.(1) These patients may experience a clinical illness that involves the central nervous system with symptoms of meningitis (e.g., fever, headache, and a stiff neck), encephalitis (e.g., drowsiness, confusion, sensory disturbances, and/or motor abnormalities such as paralysis), or meningoencephalitis.(1) Although mortality is rare, the convalescent or recovery period can be long and the incidence of sequelae may vary between 30% and 60%, with long-term or even permanent neurologic symptoms.(1) Neuropsychiatric sequelae have been reported in 10-20% of patients.(1)
How can TBE be treated?
There is no specific antiviral treatment for TBE and therapy consists of supportive care and management of complications.(1,2)
How to reduce the risk of being infected?
Safe and effective vaccines against the TBE virus exist and are recommended for people who live or work in, or travel to, TBE risk areas.(3)
The risk of tick-borne infections is reduced by avoiding tick bites (e.g. using insect repellent on skin and clothing when being in risk areas and wearing protective clothing with long sleeves, and long trousers tucked into socks or boot)(3)
As infected dairy animals can shed the TBE virus in their milk, the consumption of unpasteurised milk or dairy products in TBE risk areas is not recommended.(3)
Check your entire body if exposed to ticks and promptly removing attached ticks.(3) When checking the skin for ticks, particular attention should be paid to skin folds as ticks seek the more humid parts of the body, such as the groins, the armpits, the waistband area, under the breasts and behind the knees.(3) In young children, the head (including the scalp) and the neck area should also be checked carefully as tick bites are relatively more common at these sites in this age group. Before entering homes, clothing, bags and other belongings should be examined thoroughly for ticks.(3)
An attached tick should be removed using tweezers or fine pointed forceps, grasping it as closely as possible to where it is attached to the skin and pulling it gently upwards, trying not to break off the mouthparts. A skin disinfectant should be applied after removal of the tick to prevent infection.(3)
- Centers for Disease Control and Prevention. Factsheet TBE. Online available: https://www.cdc.gov/vhf/tbe/pdf/factsheet.pdf (Letzter Zugriff Dezember 2021)
- Centers for Disease Control and Prevention. Yellow Book 2020. Chapter 4 Travel-Related Infectious Diseases. Tickborne Encephalitis. Online available: https://wwwnc.cdc.gov/travel/yellowbook/2020/travel-related-infectious-diseases/tickborne-encephalitis (Last accessed December 2021)
- WHO. Fact Sheet Tick-Borne Encephalitis in Europe. Online available: https://www.euro.who.int/__data/assets/pdf_file/0010/246169/Fact-sheet-Tick-borne-encephalitis-Eng.pdf (Last accessed December 2021)
- Centers for Disease Control and Prevention. Yellow Book 2020. Chapter 3 Environmental Hazards & Other Noninfectious Health Risks. Mosquitoes, Ticks & Other Arthropods. Online available: https://wwwnc.cdc.gov/travel/yellowbook/2020/noninfectious-health-risks/mosquitoes-ticks-and-other-arthropods (Last accessed December 2021)
- Heinz FX et al. Emergence of tick-borne encephalitis in new endemic areas in Austria: 42 years of surveillance. Euro Surveill 2015;20(13):9–16.
- Bundesministerium Soziales, Gesundheit, Pflege und Konsumentenschutz; Impfplan Österreich 2021. Online available: https://www.sozialministerium.at/Themen/Gesundheit/Impfen/Impfplan-Österreich.html. (Last accessed December 2021)
- WHO. Fact Sheet Lyme Borereliosis. Online available: https://www.euro.who.int/__data/assets/pdf_file/0008/246167/Fact-sheet-Lyme-borreliosis-Eng.pdf. (Last accessed December 2021)