In general, exposure risks are related to those spending time in more rural regions where they may run the risk of being bitten by an infected tick. The tick which transmits tick borne encephalitis can be found all over Europe, though most cases are reported from Central and Western parts of the region. Reports are received each year from Finland to Greece, from Russia to France. Ireland and the UK are free of this disease. Due to the prevalence of the disease in Austria about 14% of the population are routinely vaccinated against this disease. This disease is found in the suburbs of Vienna and many hundreds of cases are reported in this region each year.
Most risk occurs during Spring and Summer in the forested regions of these countries. Scouts, those planning to camp or trek rurally, or those who will be living in high risk countries, especially children, should consider vaccination cover.
How is Tick Borne Encephalitis Spread?
The disease is transmitted through the bite of an infected hard back tick (Ixodes Ricinus). It is generally accepted that the tick needs to remain attached for about 24 hours before infection occurs. Careful removal of the tick at the earliest opportunity is clearly a wise precaution. Any ‘empty’ tick (no blood) will probably not have had sufficient time attached to cause infection though obviously medical advice should be sought. The typical incubation period is between 1 to 2 weeks following infection. A number of other diseases can be transmitted through infected ticks (Lyme Disease, Babesiosis, Ehrlichiosis, Typhus etc) and so, care should be taken at all times against these creatures. See our advice about preventing tick bites.
Symptoms of Tick Borne Encephalitis
The disease may range from a mild self-limiting illness to one of intense severity. It has been estimated that perhaps only 2% of all clinical infections are actually seen and there is a case fatality rate of between 1% to 2%. Common symptoms of tick borne encephalitis include fever, headache, muscular aches, and generalised influenza symptoms. In many cases the symptoms then lessen for a period (up to 1 or 2 weeks) before recurring with more severe symptoms. The encephalitis symptoms can be very prolonged and a number of those infected may develop neuropsychiatric problems.
Avoiding Infection of Tick Borne Encephalitis
As the infection is spread through the bite of an infected Tick it is obviously essential to avoid exposure when walking through the risk regions of the world. Wearing long trousers or slacks tucked into your socks and having the cuffs impregnated with permethrin will help repel the insects. It is also important to have a ‘tick hunt’ each evening to make sure no ticks escaped your best intentions during the day. Generally, most ticks will be found in skin folds throughout the body. Typically, this will be in the groin, the axilla and under the breast in a female.
Tick Borne Encephalitis Vaccination
An active vaccination against this disease is frequently used within some of the endemic countries as part of their childhood vaccination programme. For those travelling to these risk regions and who may be exposed to risk of infection (typically during the spring and summer months in the forested regions) a vaccine is sometimes recommended. This vaccine is available in Tropical Medical Bureau clinics across Ireland. The tick borne encephalitis vaccine is given on two occasions usually one month apart and then boosted between 5 to 12 months later to provide cover for about a three-year period. There is a paediatric vaccine for those from 1 to 15 years of age.