Does COVID-19 Infection during Pregnancy Increase the Appearance of Congenital Gastrointestinal Malformations in Neonates?

BACKGROUND: COVID-19 was an infection that was capable of bringing the entire world to a standstill position within a period of days to months. Despite the advancements in the medical sector, the contagion was difficult to control and costed the lives of millions of people worldwide. Many short- and long-term effects are witnessed even to date in people that contracted the disease. Pregnant females had to suffer not only the devastating effects of the virus, but also the psycho-social impact of the lockdown. The impact of COVID-19 infection during pregnancy causing decreased antenatal care or hypoxemic episodes due to severe respiratory distress and whether it could lead to the appearance of congenital gastrointestinal malformation in neonates is still unclear. The aim of our study was to analyze if COVID-19 infection during pregnancy could increase the incidence of gastric malformations in neonates born from these women. MATERIALS AND METHODS: We sifted the files of all neonates admitted into our hospital between January 2022 and December 2022, and based on inclusion and exclusion criteria, we included the cases having gastrointestinal congenital malformations during the COVID-19 pandemic. We performed a single-center, retrospective, observational descriptive study. We further divided the patients based on the anatomical location of the malformation. We also took down details of the evolution of pregnancy and whether the mother had contracted a SARS-CoV-2 infection during the pregnancy. Details regarding the Apgar score, days of intensive care admission, sex, and nutrition were the key findings studied. RESULTS: A total of 47 neonates were found to have digestive anomalies, among which, based on the anatomical locations, the number of malformation cases found at the level of the esophagus were 15, while 16 occurred at the level of the pylorus; we found 12 cases of malformation of the duodenum, and four cases had malformation of the rectum. Out of these 47 neonates, 38.3% were females and 61.7% were males. A total of 58% were preemies, among which 9% had intra-uterine growth retardation (IUGR), and 42% were full-term newborns, among which 4% had intra-uterine growth retardation (IUGR). A total of 45% of the births were primiparous pregnancies and 55% were from multiparous females. A total of 14 mothers were found to have tested positive for COVID-19 during the course of pregnancy (p-value = 0.23); many had mild symptoms but were not tested. CONCLUSIONS: COVID-19 can affect the wellbeing of the pregnant female and their fetus. Larger studies can help gain extensive knowledge as to whether COVID-19 also has the potential to result in congenital gastrointestinal anomalies in children born from COVID-19 positive mothers. In our study, only a few infants born with this pathology were found to be born from COVID-19 positive mothers. Hence, it is difficult to conclude or exclude a direct correlation between the infection and the congenital malformations.

Increased Relative Risk of Tick-Borne Encephalitis in Warmer Weather.

Tick-borne encephalitis (TBE) is a serious acute neuroinfection of humans caused by a tick-borne flavivirus. The disease is typically seasonal, linked to the host-seeking activity of Ixodes ricinus (predominantly nymphs), the principal European tick vector species. To address the need for accurate risk predictions of contracting TBE, data on 4,044 TBE cases reported in the Czech Republic during 2001-2006 were compared with questing activity of I. ricinus nymphs monitored weekly at a defined location for the same 6-year period. A time shift of 21 days between infected tick bite and recorded disease onset provided the optimal model for comparing the number of cases of TBE with numbers of questing nymphs. Mean annual distribution of TBE cases and tick counts showed a similar bimodal distribution. Significantly, the ratio of TBE cases to questing nymphs was highest in the summer-autumn period even though the number of questing nymphs peaked in the spring-summer period. However, this pattern changed during a period of extreme meteorological events of flooding and abnormally high temperatures, indicating that changes in climate affect the incidence of TBE. Previous studies failed to link human behavior with changes in incidence of TBE but showed extrinsic temperature impacts arbovirus replication. Hence, we hypothesize the apparent discrepancy between peak nymphal tick activity and greatest risk of contracting TBE is due to the effect of temperature on virus replication in the tick vector. Relative proportions of questing nymphs and the numbers of weeks in which they were found were greater in summer-autumn compared with spring-summer at near-ground temperatures >5°C and at standard day and weekly average temperatures of >15°C. Thus, during the summer-autumn period, the virus dose in infected tick bites is likely greater owing to increased virus replication at higher microclimatic temperatures, consequently increasing the relative risk of contracting TBE per summer-autumn tick bite. The data support the use of weather-based forecasts of tick attack risk (based on daytime ambient temperature) supplemented with weekly average temperature (as a proxy for virus replication) to provide much-needed real-time forecasts of TBE risk.

A serological study of antibodies to Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato in the sera of healthy individuals collected two decades apart.

Sera collected from healthy individuals from the general population in the Czech Republic during repeated cross-sectional surveys were analyzed. Samples collected in the same six districts in two time periods, 1978-1989 and 2001, were compared. The study subjects were divided into six age categories between 10 and 59 years. Overall, 434 samples from 1978-1989 and 270 samples from 2001 were screened for Anaplasma phagocytophilum (AP) and Borrelia burgdorferi sensu lato (BB). The anti-AP positivity rates were 13.1% and 11.5% in the first and second period, respectively, and did not differ significantly between the periods (P = 0.559). The anti-BB antibodies were detected in 33.9% and 14.8% of study subjects, respectively. The positivity rates were significantly lower in the second period (P<0.001). No considerable changes were observed in the sex distribution of positive findings between the two periods. The highest positivity rates of anti-AP antibodies were found in the 10-14 year age group: 16.0% in 1978-1989 and 16.7% in 2001. The age distribution of the anti-AP antibody positivity rates did not change substantially (P = 0.872). In 1978-1989, the lowest anti-BB antibody positivity rate (26.7%) was found in the 10-14 year age group, with a gradual increase with age to 41.1% in 50-59 year-olds. In 2001, the positivity rate in the 10-14 year age group was 26.2% and was not significantly different from that in the first period (P = 0.955). However, the positivity rates in the older age groups 15-59 years decreased significantly (P<0.001) and varied between 8.3% and 15.1%.

Abiotic predictors and annual seasonal dynamics of Ixodes ricinus, the major disease vector of Central Europe.

BACKGROUND: Abiotic conditions provide cues that drive tick questing activity. Defining these cues is critical in predicting biting risk, and in forecasting climate change impacts on tick populations. This is particularly important for Ixodes ricinus nymphs, the vector of numerous pathogens affecting humans. METHODS: A 6-year study of the questing activity of I. ricinus was conducted in Central Bohemia, Czech Republic, from 2001 to 2006. Tick numbers were determined by weekly flagging the vegetation in a defined 600 m(2) field site. After capture, ticks were released back to where they were found. Concurrent temperature data and relative humidity were collected in the microhabitat and at a nearby meteorological station. Data were analysed by regression methods. RESULTS: During 208 monitoring visits, a total of 21,623 ticks were recorded. Larvae, nymphs, and adults showed typical bimodal questing activity curves with major spring peaks and minor late summer or autumn peaks (mid-summer for males). Questing activity of nymphs and adults began with ~12 h of daylight and ceased at ~9 h daylight, at limiting temperatures close to freezing (in early spring and late autumn); questing occurred during ~70 % calendar year without cessation in summer. The co-occurrence of larvae and nymphs varied annually, ranging from 31 to 80 % of monitoring visits, and depended on the questing activity of larvae. Near-ground temperature, day length, and relative air humidity were all significant predictors of nymphal activity. For 70 % of records, near-ground temperatures measured in the microhabitat were 4-5 °C lower than those recorded by the nearby meteorological observatory, although they were strongly dependent. Inter-annual differences in seasonal numbers of nymphs reflected extreme weather events. CONCLUSIONS: Weather predictions (particularly for temperature) combined with daylight length, are good predictors of the initiation and cessation of I. ricinus nymph questing activity, and hence of the risk period to humans, in Central Europe. Co-occurrence data for larvae and nymphs support the notion of intrastadial rather than interstadial co-feeding pathogen transmission. Annual questing tick numbers recover quickly from the impact of extreme weather events.

Results of the Screening of Tick-Borne Encephalitis Virus Antibodies in Human Sera from Eight Districts Collected Two Decades Apart.

The sera from healthy individuals aged 10-59 years randomly selected from the general population during repeated cross-sectional surveys were stored at -20°C at the serum bank of the National Institute of Public Health in Prague. The sera included in the present study were collected in the 1980s and in 2001 in eight districts of the Czech Republic. The proportional representation of the study localities was similar in both periods. The sera were uniformly distributed in 5-year age groups for 10- to 19-year-olds and in 10-year age groups for 20- to 59-year-olds. Males and females were nearly equally represented in both periods. Altogether 704 sera, 434 from the period 1978-1989 and 270 from 2001, were screened for antibodies against tick-borne encephalitis virus (TBEV) by the virus neutralization test. The seroprevalence rates were 11.5% in the 1980s and 26.3% in 2001. From the logistic regression model, it follows that the chance of detecting anti-TBEV antibodies was more than twice higher in 2001 than in 1978-1989 (odds ratio [OR]=2.22). The differences between males and females were not statistically significant, nor was sex-period interaction. The time trends in the seropositivity rates were similar in all age groups, with the exception of the 10- to 14-year-olds (p=0.914). The rate of seropositives in the age group 15-59 years increased 1.9 times, whereas that in the age group 10-14 years rose 5.1 times. In areas comparable to those where the study sera were collected, the average incidence rates of tick-borne encephalitis (TBE) per 100,000 population aged 10-59 increased significantly from 3.35 in 1978-1989 to 8.96 in 2001 (p<0.001). The age-specific antibody trends in adult age groups in both periods suggest that clinically manifest or inapparent TBE cases do not induce lifelong immunity, but they are likely to reflect the previous epidemiological situation.

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.

[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.

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.

Chigger mites (Acari, Trombiculidae) parasitizing small mammals in the Eastern Hindu Kush and some other Afghan areas.

Chigger mites of Afghanistan were studied on the base of collections made in Eastern and Central Hindu Kush, Kabul, and some other localities. Fifteen chigger species parasitizing nine species of Rodentia, two species of Lagomorpha, and one species of Soricomorpha were found, including 13 species which were not previously recorded in Afghanistan. Eco-geographical variability is observed in Shunsennia oudemansi: Individuals of this species from high-mountain localities of Eastern Hindu Kush are characterized by larger values of most morphometric characters than the specimens collected in Kabul. Vertical and horizontal distribution of chiggers and chigger-host relationships in Eastern Hindu Kush is discussed. Comparison of our data with that on chigger fauna in the region of Tirich Mir clearly demonstrates the role of the Eastern Hindu Kush main ridge as a border between different chigger faunas.

The TICKPRO computer program for predicting Ixodes ricinus host-seeking activity and the warning system published on websites.

The computer program with the acronym TICKPRO (tick prognosis) facilitates medium-range forecasts of the level of host-seeking activity in ticks within a 1-4 day horizon. The program is based on the medium-range weather forecast routinely produced at the Czech Hydrometeorological Institute (CHMI), as well as on previously developed mathematical models describing the correlation of meteorological factors with the host-seeking activity of Ixodes ricinus. These models are based on a 6-year whole-season monitoring of I. ricinus host-seeking activity on experimental fields in the Central Bohemia Region in a typical habitat, oakhornbeam forest, where tick-borne encephalitis (TBE) virus and Borrelia burgdorferi s.str., B. afzelii, and B. garinii have been found. Meteorological data provided by the CHMI meteorological station in Prague-Libus were used, and during the development of the forecasting algorithm micrometeorological data have been collected directly at the tick monitoring sites under selected synoptic weather situations. In the TICKPRO program, the two most successful models utilized ambient air temperature, quantity of atmospheric precipitation, and relative air humidity. The prediction determines 5 levels of risk of attack according to the current proportion of host-seeking ticks, and thus determines the risk of TBE infection. The levels of risk defined by the TICKPRO program are supplemented by instructions on how to prepare oneself for entering sites with potential tick occurrence, how to move around once there, and how to behave on returning home. This warning system is weekly published on websites of National Institute of Public Health and CHMI, Prague, over entire season (March-November).

Integration of a tick-borne encephalitis virus and Borrelia burgdorferi sensu lato into mountain ecosystems, following a shift in the altitudinal limit of distribution of their vector, Ixodes ricinus (Krkonose mountains, Czech Republic).

The altitudinal shift in the limit of Ixodes ricinus occurrence above the previously established altitude of 750 m above sea level has been monitored over the long-term (2002-2008) in the Krkonose Mts. (Giant Mts.), the highest in the Czech Republic, along two vertical transects in their eastern and central parts (600-1020 and 600-1270 m). Ticks were collected by flagging three times annually, and examined individually by PCR or RT-PCR for the presence of Borrelia burgdorferi sensu lato or tick-borne encephalitis virus (TBEV). A total of 5999 I. ricinus ticks were tested. TBEV RNA was detected in 26 ticks at up to 1140 m. Demonstration of TBEV in two larvae of I. ricinus indicates transovarial transmission. Similar infection rates in larvae and nymphs show vertical transmission in TBEV circulation to be very important under these mountain conditions. B. burgdorferi sensu stricto was found at up to 1040-1065 m, Borrelia garinii and Borrelia afzelii up to 1080-1140 m, and Borrelia valaisiana up to 1270 m. The total infection rates of nymphs and larvae were 7.3% and 2%, respectively. B. garinii was the most prevalent (37%), followed by B. afzelii (29%), B. burgdorferi s.s. (11%), and B. valaisiana (9%). Double to quadruple coinfections were detected in 32% of the infected ticks, most frequently B. garinii/B. afzelii. Predominance of B. garinii and B. valaisiana over B. afzelii suggests that small passerine birds moving on the ground are responsible for permanent local populations of I. ricinus in mountain localities with low numbers of small terrestrial mammals. The detection of B. burgdorferi sensu lato and TBEV in host-seeking larvae indicates an autochthonic infection. Upon analysis of the local climate we consider climate warming to be responsible for the spreading of ticks and tick-transmitted pathogens to higher altitudes.

Vertical distribution of the tick Ixodes ricinus and tick-borne pathogens in the northern Moravian mountains correlated with climate warming (Jeseníky Mts., Czech Republic).

A study of the vertical distribution of the common tick Ixodes ricinus and tick-borne pathogens--tick-borne encephalitis virus (TBEV) and genospecies of Borrelia burgdorferi s.l.--was performed in the highest part of the Jeseniky mountain area (the Hrubý Jesenik Mts. with the highest summit Praded, 1,491 m above see level). Altogether 1,253 specimens of all tick stages (607 larvae, 614 nymphs, 8 females and 24 males) were collected at the altitude 990-1,300 m above sea level on 12 collection sites by the flagging method. Altogether 1,207 ticks (8 females, 24 males, 568 nymphs and 607 larvae) were examined for the presence of tick-borne encephalitis virus and B. burgdorferi s.l. None of the samples contained TBEV, 35 samples (6% of adult ticks, 5% of nymphs, 0.7% of larvae) were positive for B. burgdorferi s.l. The most prevalent genospecies were B. afzelii (44%), B. garinii (28%), less frequent were B. burgdorferi sensu stricto (5%), B. valaisiana (3%). The rather large number of ticks (in absolute numbers as well as recounted to the index: average number of nymphs/worker/collection hour) and the presence of all developmental stages clearly demonstrate that there are viable local tick populations in all the sites, and that recorded ticks were not randomly individuals brought into higher altitudes by birds or game animals. The results are compared with the long-term (2002-2007) monitoring of the tick altitudinal distribution in the Krkonose Mts. and the conditions, which allow ticks to establish local populations up to the timberline in both mountain areas, are discussed. Simultaneously, changes in climatic conditions (especially the air temperature) monitored at 3 meteorological stations in the area of the Jeseníky Mts. were compared with the records from another 8 stations in other mountain areas in the Czech Republic. A very similar statistically significant trend of increasing mean air temperatures during the last three decades is found at all analyzed stations. The trend is most pronounced in the spring and summer months with the highest activity of I. ricinus ticks.

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.

Extension of Ixodes ricinus ticks and agents of tick-borne diseases to mountain areas in the Czech Republic.

Along with the shift of the hard tick Ixodes ricinus to higher altitudes observed in the Czech Republic a corresponding shift of tick-borne infections to higher altitudes has been expected. Therefore, I. ricinus ticks, mainly nymphs, were investigated for the presence of tick-borne viruses, tick-borne encephalitis (TBE), Tribec and Eyach, and the spirochaete Borrelia burgdorferi sensu lato in the Sumava and Krkonose Mountains (Czech Republic). The TBE virus and different genospecies of B. burgdorferi s.l. were detected by RT-PCR and PCR, respectively. TBE virus was detected in ticks at 620 and 720 m above sea level (a.s.l.), B. burgdorferi s.l. was detected in ticks up to 1065 m a.s.l. Four genospecies of B. burgdorferi s.l. were identified, B. afzelii, B. garinii, B. burgdorferi sensu stricto, and B. valaisiana. Some nymphs carried multiple Borrelia infections. The conditions of tick-borne agents' distribution and potential epidemiological consequences are discussed.

Risk assessment and prediction of Ixodes ricinus tick questing activity and human tick-borne encephalitis infection in space and time in the Czech Republic.

Present risk assessment and prediction of future risk of humans exposed to Ixodes (I.) ricinus tick attacks and, consequently, to tick-borne encephalitis (TBE) virus infection as one of the basic preconditions for successful TBE prevention has been intensively studied in the Czech Republic. An atlas of TBE in the Czech Republic containing predictive maps of I. ricinus high-incidence habitats and TBE risk sites identified by satellite data (Landsat 5 TM with spatial resolution 30 m) at a scale of 1:200,000 over a territory of 52,000 km(2) and maps of human TBE case distribution (1971-2000) has been prepared using remote sensing and geographical information systems technologies. The influence of climate changes on a forest ecosystem inhabited by I. ricinus has been studied in the southern region of the Czech Republic. The analysis of long-term series (1931-2000) of climatologic and phenological characteristics has been carried out. The results are compared with the long-term series of TBE incidence. The influence of weather condition on day-to-day changes of I. ricinus host-seeking activities was studied in 2001-2004. Field observations were realized in the south-eastern periphery of Prague where the experimental plots for tick monitoring were established in a relevant type of forest growth (Querceto-carpinetum). I. ricinus activities were investigated by the flagging method on three plots (200 m(2) each) in weekly intervals (March to November) during 2001-2004. The instruments for micrometeorological observations were installed between the experimental plots. Macrometeorological data were used from the nearby Czech Hydrometeorological Institute first class meteorological observatory. Simple and multiple linear regression and quadratic regression were used to test the relation between weather modification and I. ricinus host-seeking activity. Two preliminary most suitable 'models' are demonstrated.

An attempt to elucidate the increased incidence of tick-borne encephalitis and its spread to higher altitudes in the Czech Republic.

In 1993 the incidence of tick-borne encephalitis (TBE) showed a sharp rise in Central Europe and has remained high since--with some slight fluctuation. This increase is clearly evident in the Czech Republic and it could be roughly characterised as twofold in 1993-2001 in comparison with 1984-1992 (5,240:2,441 human cases). As yet in the Czech Republic the TBE increase has been manifested by: a) higher number of cases in areas well known for TBE occurrence in humans; b) re-emergence in areas where TBE human cases were not observed, or only sporadically, for a long time; c) emergence of TBE in places unknown previously (including highly elevated areas). This phenomenon has not been fully elucidated yet and we would like to contribute to a better understanding of its cause by comparing the present situation with historical data. Besides TBE epidemiological data (1965-2001) we use the twenty-year all season dynamics data of Ixodes ricinus host-seeking activity (1953-1972) supplemented by the data in 1982, 1992 and by meteorological data characterising periods under study. The fluctuation in annual averages of I. ricinus occurrence was irregular. These irregularities when compared with meteorological data can be explained by different meteorological conditions in particular years. In corresponding long-time series, the peaks of I. ricinus occurrence and TBE incidence were reached at the same time. Analyses of relevant meteorological data displayed that joint I. ricinus and TBE maximal occurrence values had been preceded by mild (or warm) autumn seasons allowing a prolongation of I. ricinus activities (including development) up to November at least, thus resulting in a higher tick volume the following year. Based on these data we conclude that the increased TBE incidence rates reported in 1993 and afterwards are attributable to a more abundant occurrence of I. ricinus ticks and that their higher abundance is due to modified climatic conditions in the last decade. Such a situation has appeared in the past as well; however, it was rare and in isolated years only. At that time, although the tick population had been more abundant, in the following year it reached the usual level again. In the 1990s the prolonged mild autumn for consecutive several years led to permanently more abundant populations of I. ricinus. The same conclusion explains the shift of I. ricinus occurrence and of TBE distribution to higher altitudes in Sumava and Krkonose Mountains.

Chigger mites of the genus Eutrombicula ewing, 1938 (Acari: Trombiculidae) from Cuba, with the description of three new species.

Three new species of chigger mites, Eutrombicula cubensis sp. n. and E. anguliscuta sp. n. from lizards and bats, and E. leiocephali sp. n. from lizards, are described. One species, E. lipovskyana (Wolfenbarger, 1953), is recorded for the first time in Cuba. Data on distribution of E. alfreddugesi (Oudemans, 1910) in Cuba are reported.

Chigger mites (Acari: Trombiculidae) new to the fauna of Cuba, with the description of two new species.

Two new species of chigger mites, Hyponeoculta monocoxalae sp. n. from bats and reptiles, and Perares nudosetosus sp. n. from bats, are described. The first finding of larvae of Tectumpilosum negreai Feider, 1983 in nature is reported from a bat collected at the type locality, and the description of this species is emended. Four species, Perates monops (Brennan et Jones, 1960), Parasecia manueli (Brennan et Jones, 1960), Beamerella acutascuta Brennan, 1958, and Blankaartia sinnamaryi (Floch et Fauran, 1956), are recorded for the first time in Cuba and on new host species.