Epidemiology of Tick-Borne Encephalitis in the Czech Republic 1970–2008

Abstract

This article presents major epidemiologic features of tick-borne encephalitis (TBE) in the Czech Republic, using data of laboratory-confirmed cases since 1970. A total of 17,053 cases of TBE were reported in the Czech Republic (population 10 million) in 1970-2008. The data show several important features. First, the pattern of TBE incidence changed over time. Until the end of the 1970s, TBE was characterized by periods of alternately higher and lower incidence (between 180 and 595 cases per year); the 1980s were a period of low incidence with minimum variability; since the beginning of the 1990 s, there has been a steep rise in incidence, with marked year-to-year variation (e.g., 745 cases were registered in 1995, and a maximum of 1029 cases were registered in 2006). Second, the age distribution of TBE incidence has changed. Until the end of 1990 s, incidence peaked among those 15-19 years of age, with a gradual decline with age. In the 2000s, however, TBE incidence has been rising in those aged 60-64 years, with a sharp decline in those older than 65 years. Third, the seasonal pattern of TBE has changed markedly over time. In the earlier period, incidence had a clear peak in July/August; since the 1990 s, more cases have occurred in earlier and later months of the year. The proportion of cases occurring in April, May, October, and November increased from 9% in the 1970s to 23% in 2000-2008. Fourth, the geographical distribution of TBE also changed over time, with TBE increasingly occurring in the mountainous districts at higher altitudes. These changes in incidence patterns appear to be linked with changes in climatic and meteorological conditions. The link between climate change and TBE incidence is plausible, since TBE is a recreation-related infection associated with outdoor activities, and since climatic changes affect the life cycle of the vector.

Tick-borne encephalitis in Europe, 2007 to 2009

“…Since we have not defined the term cluster in our questionnaire, we assume that contact points have interpreted this differently. Alimentary infection is well known leading to such clusters and three countries reported such events during the observation period [17][18][19]. The other clusters may also relate to an undiscovered alimentary source or may relate to a natural focus with high prevalence of TBE virus in ticks and a high local transmission (e.g.…”

“…In addition, co-feeding of infected and non-infected ticks on the same host as well as trans-stadial and trans-ovarial transmission of the virus, play a major role in virus transmission [13]. While most TBE virus infections of humans occur following the bite of an infected tick, alimentary routes of TBE virus transmis-sion by raw milk consumption have also been described [14][15][16][17][18][19].…”

Scientific Opinion on the public health risks related to the consumption of raw drinking milk

“…In the Czech Republic, between 1997 and 2008, there were 7 288 cases of TBEV infection reported, of which 64 (0.9 %) were considered to be food-borne. These were mostly family outbreaks and included the involvement of unpasteurised goat's milk (Kriz et al, 2009). Kerbo et al (2005) reported an outbreak from Estonia in 2005 linked to raw goat's milk.…”

Tick-borne encephalitis in Slovenia (1953-2013): the 60th anniversary

“…Parez pri tej obliki niso opazili. Ozdravljenje je popolno, brez trajnih posledic (31)(32). Virus prizadene tudi miokard, jetra in druge organe.…”