Infectious diseases you’ve probably never heard of Part III: TICK-BORNE ENCEPHALITIS
We’ve all heard of malaria, dengue fever, typhoid fever and hepatitis. These are all common infectious diseases we hear about while traveling, especially in developing countries. But what about the lesser known infectious diseases? Like tick-borne encephalitis, which is often found in more developed countries. Are you at risk?
What is tick-borne encephalitis?
Tickborne encephalitis (TBE) is a virus that affects the central nervous system and is spread through the bite of an infected tick. Ticks will bite humans and may stay attached for several days but it only takes seconds after being bitten for the virus to be transmitted. TBE is more rarely spread when ingesting unpasteurized dairy products from infected goats, sheep or cows. It cannot be spread from person to person. Most cases occur in rural areas during the highest tick-biting period between April to November.
Are you at risk?
The disease occurs in many parts of Europe, the former Soviet Union and Asia. The highest number of cases are in the Baltic states (Estonia, Latvia, and Lithuania), Russia, and Slovenia. Other high-risk countries include Albania, Austria, Belarus, Bosnia, Bulgaria, China, Croatia, Denmark, Finland, Germany, Greece, Hungary, Italy, Mongolia, Norway, Poland, Korea, Romania, Serbia, Slovakia, Sweden, Switzerland, Turkey and Ukraine.
The risk for travellers is highest when camping and hiking in forested areas of countries at risk, especially from April to November. Hunters and farmers are also potentially at increased risk. Ticks infected with TBE have also been found in wooded suburbs and urban parks in Europe, Scandinavia, the Baltic States, Russia, and China. Approximately 5,000 to 13,000 cases of TBE are reported every year, but this number is likely largely underestimated. The risk to travellers is about 1-10 per 100,000 travellers per month of travel.
What are the symptoms?
Most TBE infections do not cause any symptoms. When symptoms occur, they usually begin 4-28 days after infection (median 8 days). Symptoms of the disease usually occur in two phases. The first phase causes general flu-like symptoms including fever, headache, fatigue and muscle pain, lasting for a few days. Usually two thirds of people will recover following these symptoms. The other one third will experience a second phase causing high fever, neurological symptoms, and muscle paralysis. The disease is often more severe in adults ≥50 years of age.
Is there treatment?
There is no treatment for TBE. Travellers who develop illness or a local reaction within 2-3 weeks after a tick bite should seek medical attention. The ticks that transmit TBE can also spread Lyme disease and other infections.
Preventing tick-borne encephalitis
The TBE vaccine is not available in Canada or the U.S but there are two types of TBE vaccines available in Europe, FSME-IMMUN and Encepur. Both vaccine series consists of 3 doses given over ≥ 6 months. A rapid series is also available for each vaccine. Travellers who will be at high risk for TBE can arrange to receive the vaccine on arrival to their destination. However, protective antibodies do not develop until 4 weeks after the vaccine series is started, so for many travellers avoiding tick bites may be more practical than receiving the vaccine.
TBE can be avoided by:
- Avoiding consumption of unpasteurized dairy products
- Wearing long pants tucked into socks or boots
- Wearing closed shoes instead of sandals
- Minimizing exposed skin when walking through brushy vegetation
- Wearing light coloured clothing so ticks can more easily be seen
- Applying repellants with ≥20% DEET to exposed skin
- Sleeping in screened tents when camping
- Performing a full-body tick check daily when staying in areas where TBE is a risk
- Removing ticks as soon as possible with forceps
So now you’ve learned about tick borne encephalitis, a lesser known infectious disease. You don’t always need to be travelling to developing countries to be at risk of disease!
TravelSafe Clinical Educator – Kristin Cain, RN, BSc, MSc(A)