Effectiveness of primary vaccination against tick-borne encephalitis in employees of the armed forces.

OBJECTIVE: The aim of our study is to evaluate immune response after receiving the primary vaccination against tick-borne encephalitis (TBE), and to establish a link between seropositivity and selected factors in soldiers. METHODS: Blood samples, questionnaires and vaccination records were obtained. TBE antibodies were detected using both ELISA and a neutralization test (NT). We used logistic regression for statistical analysis. RESULTS: Overall, seropositivity (presence of IgG) was detected in 88% of participants. The proportion of seropositive subjects in relation to the number of doses of vaccine was 69% (2 doses) and 91% (3 doses). A statistically significant relationship was found between seropositivity and the number of vaccine doses. No statistical significance was identified in relation to age and sex. There was no statistical significance of seropositivity, depending on the time of the last dose of the vaccine. CONCLUSIONS: TBE immunisation should be targeted at individuals in the most affected locations and those at highest risk of exposure according to lifestyle and occupation.

Milk outbreaks of tick-borne encephalitis in Slovakia, 2012-2016.

OBJECTIVE: Tick-borne encephalitis virus (TBEV) is most commonly transmitted to humans via the bite of an infected tick. Alimentary infection through the consumption of TBEV-contaminated dairy products is also well-documented and is responsible for some diseases in endemic areas. The aim of the study was to emphasize the risk of contracting tick-borne encephalitis (TBE) by consuming raw milk and dairy products and to describe TBE epidemics in Slovakia for the period 2012-2016. METHODS: The data on epidemics were obtained from the Annual Reports for the period 2012-2016 available on the website of the Public Health Authority of the Slovak Republic. Medical records of patients hospitalized during epidemics were provided by the Department of Infectology and Travel Medicine, Faculty of Medicine, Pavol Jozef Safárik University in Kosice, and the Louis Pasteur University Hospital in Kosice. RESULTS: During the period 2012-2016, 13 smaller or larger TBE epidemic outbreaks were recorded in the Slovak Republic. The two outbreaks of TBE reported in 2012 were associated with the consumption of raw goat's milk and dairy products. The first case was an outbreak involving 12 infected people in the Lucenec District. The second case was a family outbreak in the Zilina District, where 3 persons out of 4 family members were infected. In 2013, one epidemic was reported involving 5 persons following the consumption of sheep's cheese from a farm in the Presov District. One outbreak with 11 cases was reported in 2014. The investigation confirmed its association with the consumption of sheep's cheese in a restaurant located in the Ruzomberok District. In 2015, 4 epidemics were described related to the consumption of goat's/sheep's milk and cheese (Zilina District, Krupina District, Kysucké Nové Mesto District, Trencín District). In 2016, there were 5 TBE epidemics related to the consumption of milk and dairy products. The largest TBE epidemic outbreak in the last 5 years occurred in the Kosice District. In this outbreak approximately 500 people were exposed, and 44 contracted the disease. Infected persons confirmed consumption of sheep's cheese from a farm. CONCLUSIONS: Consumption of milk and dairy products made only from pasteurized milk, as well as the immunization of humans and animals are the most effective preventive measures against TBE.