Ticks hike to hitherto unknown heights

Experts of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE) have long been warning of the dangers of tick-borne encephalitis (TBE) – now mountain hikers are among those in danger. Because ticks, too, have been climbing higher.

(Vienna, 29 January 2009) – Climate change and global warming have also had an influence on the geographical distribution of ticks. Not only have ticks infected with the TBE virus spread to previously unaffected regions, the year 2008 also marked the first time these infected ticks have been detected at more than 1,500 meters above sea level. As a result, hikers, trekkers, and mountain bikers now face the danger of contracting TBE. The ISW-TBE has been calling for vaccination against TBE to become a standard preventive measure for everybody traveling to endemic regions. TBE is an infection of the central nervous system. According to estimates of the World Health Organization (WHO), between 35–58% of TBE patients are left with long-term neurological sequelae, such as paralysis, and some 2% of patients die of the disease. Every year, about 10,000 persons contract the infection through the bite of an infected tick.

TBE – transmitted through goat cheese
In 2008, an exceptional case of TBE hit the Austrian media: A family from Austria’s westernmost province of Vorarlberg contracted TBE, the virus having been transmitted through the milk of one of their goats, which had been infected. The case occurred at more than 1,500 above sea level. “This is one of the relatively rare Austrian cases of the virus being transmitted through the food chain. Had the family been vaccinated, this case of TBE could have been prevented,” comments Professor Franz Xaver Heinz, Institute of Virology, Medical University of Vienna.

Increased mobility – increased risk
Changes in lifestyle have lead to increased mobility – a positive trend, which, however, has also increased the risk of spreading infectious diseases. Even though the TBE virus is not transmitted from human to human, travelers to endemic regions failing to undergo vaccination may suffer far-reaching consequences when bitten by a tick. “Based on statistical modeling, it has been estimated that the likelihood for an unvaccinated tourist to acquire TBE in a highly endemic region – mainly Central Europe – is similar to the risk of acquiring typhoid fever in India. Travelers to India are generally recommended to undergo vaccination against typhus, whereas travelers to Central Europe are only rarely made aware of the importance of TBE vaccination,” says DDr Martin Haditsch, Institute for Hygiene, Microbiology, and Tropical Medicine, Krankenhaus der Elisabethinen, Linz.

Professor Pier Luigi Lopalco from the European Centre for Disease Prevention and Control (ECDC) has been working to close this gap. The ECDC is an agency of the European Union whose mission is to help strengthen Europe’s defenses against infectious diseases. “Even though TBE is not yet on the list of notifiable diseases at a European level,” says Professor Pier Luigi Lopalco from the European Centre for Disease Prevention and Control (ECDC), “we have been working to raise awareness of its dangers to motivate people to get vaccinated.” Once infected with the virus, there is still no causal treatment available to halt infection. “The neurological risks associated with TBE are immense,” emphasizes neurologist and psychiatrist Primarius Dr Ulf Baumhackl, St. Pölten, “and patients often require intensive care.”

Epidemiology of TBE
TBE is a notifiable disease in 16 European countries (Austria, the Czech Republic, Estonia, Finland, Germany, Greece, Hungary, Latvia, Lithuania, Norway, Poland, Russia, Slovakia, Slovenia, Sweden, and Switzerland). “Since 1990, over 157,500 cases of TBE have been registered in Europe, corresponding to 8,755 cases annually. Its climatic conditions make Austria a high-risk country for TBE. However, because vaccination coverage is exceptionally high, the number of cases has come down from 677 in 1979 to 86 in 2008,” explains Professor Jochen Süss, Friedrich-Löffler-Institute, Jena. From 2007 to 2008, the number of cases increased slightly, as trend seen throughout Central Europe. Men are more often affected by TBE than women. “These figures speak a clear language, emphasizing how important it is to adequately inform the public and take targeted public-health measures,” concludes Süss.

Patient Advocacy Group also warns of the dangers of TBE
The TBE Patient Advocacy Group “Tick Victim” was founded in 1986 and has since been active at raising awareness of TBE at both a national and international level. One of the missions of the group is for tick victims to pass on their experiences to the public to make the danger of TBE visible. Many of the members of the advocacy group are themselves sufferers of the after-effects of TBE, such as concentration difficulties, reduced performance, depressive mood, and other forms of neurological or psychological impairment. Christine Freund, chairwoman of the Austrian TBE Patient Advocacy Group, stresses once more that “TBE is a 99% preventable disease. Many of our most severely affected members would gladly turn back the wheel of time and get vaccinated.” The message from those affected by TBE to those not yet vaccinated is clear: “The only way to guard against TBE is preventive vaccination.”

ISW-TBE: Ten Year Anniversary
For more than 10 years, the international working group ISW-TBE has been devoted to the fight against the potentially life-threatening TBE virus. The group comprises internationally recognized experts from endemic regions. “At a high scientific level, we have intensively and successfully worked to enhance awareness of the dangers of TBE among both public-health institutions and individuals,” says Professor Michael Kunze, chairman of the ISW-TBE and head of the Institute for Social Medicine, Medical University of Vienna.

On the occasion of its 10-year anniversary, the ISW-TBE has published a celebration brochure providing a comprehensive historical review of the activities and achievements of the organization. Experts and journalists can order the brochure free of charge by contacting Public Health PR.

For more information, please go to:
www.ISW-TBE.info, www.TBE-prevention.info, and www.tick-victims.info.

Kunze, Baumhackl, Süss, Freund, Lopalco, Haditsch, Heinz

See www.publichealth.at for more photos of the press workshop.