Tick-borne encephalitis in Slovakia – epidemiology and history

Abstract

Tick-borne encephalitis (TBE) is still the serious health problem despite seventy years beeing the object of many studies in natural focuses, available vaccine and large amount of knowledge about its epidemiology and prevention. TBE is in Slovakia the most important arboviral infection. History of complex study of basic principles and causes of TBE occurrence by investigation of biology of ticks, sourc-es of infection and ecologic relations (biotop, biocenosis, climatic and natural factors) together with discovery of its natural focuses started in the former Czechoslovakia after the large outbreak in Rožňava (east Slovakia) in 1951, when 660 individuals contracted infection by drinking unpasteurized goat´s milk. Analysis of this epidemic initiated research of focuses in Slovakia by epidemiological and virological investigations of ticks, reservoirs (rodents, insec-tivores), antibody prevalence in inhabitants and possibilities of alimentary transmission in experiment and focuses. During the last decade an increase of TBE morbidity was notified in EU/EEA, in 2020 3734 cases (incidence 0.89 / 100 000) were reported. Similar trend was observed in Slovakia, in 2020 incidence was 3.39 / 100 000, 185 people were ill. There was also recorded the rise of infections caused by consumption of unpasteurized cheese and raw goat’s, sheep’s and cow’s milk. In the years 2010–2020 27 food-borne outbreaks were reported in the regions (Trenčín, Banská Bystrica, Žilina, Košice) mostly in June and July. The largest epidemic was in Košice suburbia in 2016. Two cases among 0–1 years old children were reported, one caused by tick attack and another one by breast--feeding. Therefore prevention must be concentrated on education, control of milk products in small diary farmings, personal and professional protection against ticks and vaccination against TBE.