Tick-borne encephalitis (or TBE, Tick-borne Encephalitis) is a diseaseof viral origin, in which the virus is transmitted to humans in two main ways:
Most people infected with tick-borne encephalitis do not feel sick. When they do occur, symptoms may include fever, aches, loss of appetite, headache, nausea and vomiting, while in some cases swelling of the brain and/or spinal cord, confusion and sensory disturbances develop. Tick-borne encephalitis can even go so far as to cause death.
Travelers in many parts of Europe and Asia may be at risk of infection.
Russia has the largest number of reported cases, while the highest incidence of the disease has been reported in Western Siberia, Slovenia, and the Baltic states (Estonia, Latvia, Lithuania).
Other European countries with reported cases or known endemic areas include Albania, Austria, Belarus, Bosnia, Croatia, Czech Republic, Denmark, Finland, France, Germany, Hungary, Italy, the Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Sweden, Switzerland, and Ukraine. Asian countries with reported TBE cases or viral activity include China, Japan, Kazakhstan, Kyrgyzstan, Mongolia and South Korea.
Activities that increase a traveler's chances of contracting tick-borne encephalitis include camping, hiking and hunting. Travelers are more likely to be infected with tick-borne encephalitis when they travel to affected areas from April to November, which is the time when ticks are most active.
The first and most immediate form of defense is the use of insect repellents. Travelers can then protect themselves from tick-borne encephalitis by taking the following precautions:
Prevent tick bites:
It is important to examine your clothing carefully:, ticks can be carried indoors on clothing. When you return, it is good precaution to dry them in the dryer for ten minutes to kill ticks on dry clothing (if they are damp, however, it may take longer). In case the clothes requirewashing first, hot water is recommended: water at low or medium temperatures is not enough to kill ticks.
Tools, coats, backpacks and pets must also be examined: which are another vector by which ticks can enter the home, to attach to a person later.
Another useful step upon returning home is to take a shower. Showering within two hours of entering the home has been shown to reduce the risk of contracting tick-borne diseases: in addition to being a good opportunity to get checked out, it can help wash away unattached ticks.
No TBE vaccine is licensed or available in the United States. Two TBE vaccines derived from inactivated cell cultures are available in Europe in adult and pediatric formulations: FSME-IMMUN (Pfizer, France, also marketed as TicoVac) and Encepur (GSK, Germany). Two inactivated TBE vaccines are available in Russia: TBE-Moscow (Chumakov Institute) and EnceVir (Microgen). SenTaiBao (Changchun Institute of Biological Products in China) also produces an inactivated TBE vaccine. Studies on immunogenicity (the ability to elicit an immune response) suggest that the European and Russian vaccines provide cross-protection against all 3subtypes of TBE virus.
Although formal efficacy studies of these vaccines have not been conducted, immunogenicity data and postlicensure efficacy studies suggest that their efficacy is >95%. Rare vaccine failures have been reported, particularly in people over 50 years of age.
Because the routine primary vaccination series takes more than six months to complete, most travelers to TBE endemic areas will find it more practical to avoid tick bites than vaccination. However, a rapid vaccination schedule for both European vaccines has been studied, and seroconversion rates are similar to those observed with standard vaccination schedules.
Travelers who plan to be in high-risk settings for extended periods, for example working or campingin forested areas or farmland, or living in countries endemic to TBE,should in any case consider vaccinating in Europe.