Increasing Residential Proximity of Lyme Borreliosis Cases to High-Risk Habitats: A Retrospective Study in Central Bohemia, the Czech Republic, 1987-2010.

An analysis of historical data on Lyme borreliosis in Central Bohemia between 1987-2010 has revealed that the rate of peri-domestic exposure, the proximity of patients' residences to high-risk habitats, and the number of disease cases have been interdependent variables and that their common upturn can be dated back to the start of the 1990s or earlier. The data indicate that the disease rise is attributable to translocation of part of the at-risk population nearer to natural environments, rather than to mere intensification of people's peri-domestic exposure at existing residential locations, or changes in the natural environment itself.

The role of game (wild boar and roe deer) in the spread of tick-borne encephalitis in the Czech Republic.

In the Czech Republic, the incidence of human tick-borne encephalitis (TBE) has been increasing over the last two decades. At the same time, populations of game have also shown an upward trend. In this country, the ungulate game is the main host group of hosts for Ixodes ricinus female ticks. This study examined the potential contribution of two most widespread game species (roe deer [Capreolus capreolus] and wild boar [Sus scrofa]) to the high incidence of TBE in the Czech Republic, using the annual numbers of culls as a proxy for the game population. This was an ecological study, with annual figures for geographical areas-municipalities with extended competence (MEC)-used as units of analysis. Between 2003 and 2011, a total of 6213 TBE cases were reported, and 1062,308 roe deer and 989,222 wild boars were culled; the culls of roe deer did not demonstrate a clear temporal trend, but wild boar culls almost doubled (from 77,269 to 143,378 per year). Statistical analyses revealed a positive association between TBE incidence rate and the relative number of culled wild boars. In multivariate analyses, a change in the numbers of culled wild boars between the 25th and 75th percentile was associated with TBE incidence rate ratio of 1.23 (95% confidence interval 1.07-1.41, p=0.003). By contrast, the association of TBE with culled roe deer was not statistically significant (p=0.481). The results suggest that the size of the wild boar population may have contributed to the current high levels and the rising trend in incidence of TBE, whereas the regulated population of roe deer does not seem to be implicated in recent geographical or temporal variations in TBE in the Czech Republic.

Peri-urbanisation, counter-urbanisation, and an extension of residential exposure to ticks: a clue to the trends in Lyme borreliosis incidence in the Czech Republic?

The incidence of tick-borne human diseases (TBD) in the Czech Republic (CZ) is on the increase, driven by infections increasingly acquired in residential locations, earlier in spring and later in autumn, and among children and the elderly. To interpret these trends, data on Lyme borreliosis (LB) incidence between 1997 and 2010 were analysed in the context of population migration flows registered in the CZ during the same period. Analysis showed that a migration stream of families with children, and of the elderly, flowed from more urbanized and densely populated localities to those more rural and less populated, where the chance of acquiring LB in the home vicinity was greater than in the urban settings. By contrast, a stream of people in the life phase between early adulthood and family formation flowed reversely, corresponding to a prominent absence of this age category from the patient spectrum. The data further showed that the more the residential exposure became prevalent, the more people were in year-round (rather than in summertime only) contact with ticks, which accounts for an extension of the cases' seasonal distribution as well as for an overall increase in case numbers. Finally, the fact that majority of the urban-to-rural migrants could be categorised as wealthier people could explain the previously noticed lack of low-status people among TBD patients in the CZ.

Spatial distribution of a population at risk: an important factor for understanding the recent rise in tick-borne diseases (Lyme borreliosis and tick-borne encephalitis in the Czech Republic).

Recent rise in tick-borne diseases in many parts of Europe is a phenomenon in need of an explanation. We analyzed temporal trends in spatial distribution of a population at risk of Lyme borreliosis, tick-borne encephalitis, and as a control, also of a 'non-tick-borne disease' in the Czech Republic in 1997-2010. Analysis revealed that the population's exposure had been increasingly confined to the nearest surroundings of residences or in totally residential locations and that the incidence of the diseases depended in some causal way on how close to residences people exposed themselves to the risk. The rise in Lyme borreliosis and tick-borne encephalitis was solely due to infections acquired at or near patients' homes (<5 km), while the number of cases acquired further away was decreasing. The detected patterns in the data question some of the hypotheses which may be applicable in explaining the rise in disease incidences in the Czech Republic including the effect of climate change. Potentially causal factors are discussed.

[Incidence of tick-borne encephalitis in the czech republic in 2001-2011 in different administrative regions and municipalities with extended power]. / Incidence onemocnení klístovou encefalitidou v Ceské republice v letech 2001-2011 v jednotlivých krajích a obcích s rozsírenou pusobností

AIM: Analysis of the incidence of tick-borne encephalitis (TBE) in the Czech Republic (CR) in 2001-2011 in different administrative regions and municipalities with extended power (MEPs). MATERIAL AND METHODS: Each TBE case reported to the EPIDAT system was matched to the respective MEP or Prague according to the place of residence. The annual TBE incidence was calculated per 100 000 permanent residents (mean) of each administrative region and MEP. The overall incidence, age-specific incidence, and average incidence by administrative region per year and per the eleven-year period were calculated. RESULTS: In the study period, the highest TBE incidence rates were found in the Plzen Region, South Bohemian Region, and Highlands Region, neighbouring with Germany and Austria. The overall TBE incidence in the CR had a slightly upward trend resulting from different subtrends in various administrative regions. The overall trend was most influenced by the most affected regions with opposite trends - the Highlands Region and the South Bohemian Region. The South Bohemian Region with the highest average incidence in the study period of 23.4/100 000 population also showed the maximum effect on the country-wide age-specific incidence due to the trend in the age--specific incidence, sharply rising to peak in the age group 60-64. As it had long been the region with the highest incidence in the Czech Republic, vaccination campaigns were organized repeatedly there, targeting high-risk areas and children. The vaccine coverage rate in school-age children in the last decade was about 50%. The analysis of age group trends showed no considerable increase in 0-14-year-olds in 2011, i.e. the year with the second highest TBE incidence ever reported in the CR, in contrast to 15 to 44-year-olds where the TBE incidence rates were three times as high. From this it can be inferred that the post-vaccination antibody level and its protective effect wane over years unless a booster dose is given. The incidence trend for TBE in 45-64-year-olds, i.e. the age group who lived life long inside or close to the most active TBE foci, suggests that the contact with the TBE virus does not induce protective herd immunity. The analysis of TBE incidence in the population of smaller administrative areas provides more detailed information. In six MEPs, the average TBE incidence over the 11-year period was more than 30/100 000, with a peak of 58/100 000. CONCLUSION: Although the most important epidemiological information for a disease with natural focality is the place of acquisition of infection, the long-term evaluation of TBE incidence according to the patients place of residence is also relevant. The data on TBE incidence in the population of 205 MEPs provide helpful information for campaigns to reduce the risk of TBE infection targeted to human behaviour in TBE natural foci and preventive measures, particularly vaccination. It cannot be excluded that residents of high-risk areas will continue risky behaviour even in the future.

[Differences in the incidence of viral hepatitis A and E in the Czech Republic]. / Odlisnosti výskytu virových hepatitid A a E v Ceské republice.

Although both viral hepatitis A (VHA) and E (VHE) are typically acquired by fecal-oral transmission, they differ in the incidence, particularly in the age-specific incidence, with VHA being reported most often in pre-school age and school age children but also in young adults while VHE often occurs in adults. VHA is common in persons from socially weak communities. Higher incidence has been reported in autumn months as a result of infection acquired during the holidays. VHE is typically acquired in cold months of the year and VHE cases are often associated with home slaughtering. To prevent both types of hepatitis it is necessary to drink safe water and to adhere to rules of personal and operational safety while preparing food. The prevention of VHA consists in active immunization, while that of VHE requires primarily that pork meat and offal should be heat processed and cross contamination between raw materials and final products should be avoided. For both types of hepatitis, epidemiological history and adequate diagnosis are prerequisites for the adoption of effective antiepidemic measures.

Rotavirus gastroenteritis in the Czech Republic before the start of vaccination.

BACKGROUND: The primary objective of our study was to investigate rotavirus gastroenteritis (RVGE) retrospectively in the Czech Republic (CzR) and try to estimate its significance in the most affected age groups in the prerotavirus vaccine era. METHODS: To analyze the epidemiological data on RVGE in the CzR, two databases were used retrospectively. The first database consisted of regular yearly reports from the laboratories diagnosing rotavirus infections from 1998 to 2006. The second database used was EPIDAT (the official notification system of the hygiene service). The data from 1998 to 2006 was analysed. RESULTS: From 1998 to 2006, the laboratories reported 1,430 to 4,815 cases of RVGE per year. By extrapolation--, in the CR in 2006, there were an estimated 4,076 rotavirus-related hospitalizations (696.7/100,000 in the age group < 5 years). The most commonly applied detection systems in 2006 were immunochromatography and latex agglutination. Of the RVGE cases recorded in the Epidat database between 1998-2006, 76.0-89.2% were for children aged less than five years. Seasonality was observed with the highest incidence rates between January and May with most cases usually occurring in March. Over nine years, there were six deaths linked directly to RVGE - three -deaths reported in children under two and three deaths reported in elderly people whose deaths were related to the epidemics in retirement homes. CONCLUSIONS: The estimated incidence rates of RVGE hospitalization in 2006 was higher in the CzR than that reported in other industrialized European countries. Our findings might verify the need for rotavirus vaccine implementation in the Czech Republic and reinforce the importance of rotavirus gastroenteritis surveillance.

Epidemiology of tick-borne encephalitis in the Czech Republic 1970-2008.

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.

[Congenital rubella syndrome - case report]. / Vrozený zardenkový syndrom - kazuistika.

The goal of this case report is not only to describe a case of congenital rubella syndrome that is currently rarely seen in the Czech Republic but also to emphasize the importance of vaccination against rubella. Rubella usually occurs in susceptible children as a mild illness with rush. Its association with abortions and severe congenital disabilities was noticed in the 1940s. Since that time, efforts have been made to develop a vaccine against rubella to prevent congenital rubella syndrome.

Spatio-temporal variation of tick-borne encephalitis (TBE) incidence in the Czech Republic: is the current explanation of the disease's rise satisfactory?

A marked increase in tick-borne encephalitis (TBE) incidence has been observed in Europe during the last 2 decades. Hypothetical causes include global climatic fluctuations, human-induced environmental changes, and socio-economic changes. These factors are thought to be disproportionately relevant in different geographical areas. To date, epidemiological studies of this phenomenon were based primarily on aggregated data, and little is known about TBE dynamics on the detailed geographical scale. This study is aimed at the subregional variations of incidence of TBE in the Czech Republic. The methodology of spatial statistics was applied. Over 13,000 cases of TBE, registered 1971-2007, were pinpointed on a GIS map and analysed for density variations in both time and space. Selected areas were studied in detail, using time series analysis. These analyses revealed that the incidence of TBE was highly variable both across the country and over the study period. Although the aggregate total of reported cases were generally increasing, local trends were divergent. A detailed study of one endemic area (that one with the highest case density level) showed that heterogeneities are detectable, even on a very fine geographical scale. There was no evident spatial coherence of the TBE trends; and some adjacent areas showed quite differing trends. However, countrywide coherence was demonstrated for quasi-octennial fluctuations in the TBE series, associable with the North Atlantic oscillation. The possible influences of both various climatic and population covariates upon TBE occurrence are discussed. However, the geographical heterogeneity of the disease trends, at such a fine spatial scale, cannot be explained satisfactorily by fluctuations in climatic or socio-economic conditions.

Influence of climate warming on tickborne encephalitis expansion to higher altitudes over the last decade (1997-2006) in the Highland Region (Czech Republic).

The steep rise in the incidence of tick-borne encephalitis (TBE) in the 1990s and its subsequent high level in the Czech Republic are not even over the whole territory. It is manifested markedly in the Czech-Moravian Highland region. In the decades of 1971 through 1992, TBE incidence in the Highland Region did not reach the countrywide average. The rise has been noted only since 1997; in the year 2006 TBE incidence in that administrative region was more than double the countrywide average. Analysis of the situation have not found any socio-economic shifts or land-use changes, or in the numbers of game animals, that could have had an effect on TBE incidence. The rise of infections in localities 500 m above sea level (a.s.l.) and more was markedly steeper than that below that altitudinal limit. At those altitudes there has been found an increase in average monthly temperatures exceeding countrywide averages namely in the period of maximum Ixodes ricinus activity (May-August). Detailed analysis of meteorological conditions and comparison with a long-term study of the influence of modifications of the mountain climate in the Krkonose Mts. on I. ricinus tick distribution and the pathogens transmitted by them, have led to the conclusion that likewise in the Czech-Moravian Highland a marked warming had influenced the local population of the vector I. ricinus, caused an activation of foci of TBE, increased contacts of humans with the vector, consequently giving rise to an apparent increase in the incidence of human cases of TBE.

[The effect of routine vaccination in the Czech Republic on the incidence of invasive diseases caused by Haemophilus influenzae b].

OBJECTIVES: The paper is an analysis of the results of a five-year surveillance programme in the Czech Republic (1999-2003); it evaluates the efficacy of routine Hib vaccination that started in July 2001. MATERIAL AND METHODS: Morbidity due to Hib was explored in a surveillance programme, which since 2002 also included the investigation of Hib vaccine failure. Hib identification was carried out with standard methods, serotypes were verified using PCR, biotyping was carried out in all strains and in selected strains also multilocus sequential typing. RESULTS: In the years 1999-2003 invasive Hib disease presented mostly as meningitis, followed by epiglottitis. Mortality due to an invasive Hib disease was in the years 1999-2003 2.3 %. Among the Hib strains isolated in invasive disorders predominated the biotype I and the sequence type ST-6. CONCLUSIONS: Following the introduction of routine Hib vaccination in the Czech Republic there was an overall drop in morbidity due to Hib invasive disorders. This was most obvious in a decrease in the morbidity of Hib meningitis and in the vaccinated age group. Two years after the introduction of routine Hib vaccination morbidity dropped by 81 % in children aged 0 to 1 year. In higher age groups there was no change in the number of invasive Hib disease. Neither was there an increase in "non-b" haemophilus invasive disorders. Failure of Hib vaccination is a rare occurence.