Tickborne encephalitis

Tickborne encephalitis (TBE) also known as spring-summer encephalitis, is a viral infection of the central nervous system transmitted by bites of certain vector ticks. The disease occurs in Scandinavia, Western and Central Europe and countries that comprise the former Soviet Union.

Risk of acquiring the disease is greatest from April through August when Ixodes ricinus, the principal tick vector, is most active. TBE is common in Austria, the Czech Republic, Slovakia, Germany, Hungary, Poland, Switzerland, Russia, Ukraine, Belarus, and northern Yugoslavia. It occurs at a lower frequency in Bulgaria, Romania, Denmark, France, the Aland Islands and neighboring Finnish coastline, and along the coastline of southern Sweden, from Uppsala to Karlshamn. Serologic evidence for TBE infection or sporadic cases have been reported from Albania, Greece, Italy, Norway, and Turkey. A closely related disease, Russian spring-summer encephalitis, transmitted by Ix. persulcatus ticks, occurs in China, Korea, and eastern areas of Russia.

The severity of disease, incidence of sequelae, and case-fatality rates are higher in the Far East and eastern regions of Russia than in western and central Europe.

Human infections follow bites of infected ticks, usually in persons who visit or work in forests, fields or pastures. Infection also may be acquired by consuming unpasteurized dairy products from infected cows, goats, or sheep.

The risk to travelers who do not visit forested areas or consume unpasteurized dairy products is low. Travelers should be advised to avoid tick infested areas and to protect themselves from tick bites by dressing appropriately and using repellents.

The repellent N,N-diethyl-metatoluamide (DEET) can be applied either to clothing or directly on the skin. Compounds containing permethrin have an acaricidal and repellent effect and should be used on clothing and camping gear.

Although effective vaccines may be obtained in Europe from Immuno, Vienna, Austria, and Behring, Germany, available data do not support a recommendation for its use in travelers.

Diseases