Hepatitis E virus in archived sera from wild boars (Sus scrofa), Czech Republic.

To determine whether hepatitis E virus (HEV) was distributed in the population of wild boars in South Moravia between 1990 and 2008, a total of 366 samples of archived sera from wild boars were investigated using serological (commercial ELISA) and molecular (RT-qPCR) methods. A total of 31 (8.5%) wild boars were seropositive, and from two of them, RNA sequences were recovered by nested RT-PCR. The presented results, with one of the oldest animal's HEV-positive serum (collected in 1990), suggest that wild boars may be a reservoir of HEV in the Czech Republic and that this virus has been circulating in studied areas for more than 20 years.

Serological Survey for West Nile Virus in Wild Artiodactyls, Southern Moravia (Czech Republic).

Antibodies to West Nile virus (WNV) were examined by plaque-reduction neutralization test in the blood sera of 1023 wild artiodactyls: 105 roe deer (Capreolus capreolus), 148 red deer (Cervus elaphus), 287 fallow deer (Dama dama), 71 mouflons (Ovis musimon), and 412 wild boars (Sus scrofa), sampled in South Moravian district of Breclav (Czech Republic) in the years 1990-2008. Neutralizing antibodies were detected in 5.9% of wild ruminants (4.8% roe deer, 4.1% red deer, 6.3% fallow deer, 9.9% mouflons) and 4.1% of wild boars, with titers ranging between 1:20 and 1:320. The results indicate that WNV has circulated in wild artiodactyls at a variable frequency during the years in the area.

Serological survey of domestic animals for tick-borne encephalitis and Bhanja viruses in northeastern Hungary.

Blood sera collected from 400 domestic animals (260 cattle, 100 Merino sheep, and 40 Hutzul horses) in northeastern Hungary in 2005 were examined for antibodies against two tick-borne viruses, tick-borne encephalitis flavivirus (TBEV) and Bhanja bunyavirus (BHAV). Using ELISA as screening test and plaque-reduction neutralization as confirmatory test, seropositivity to TBEV was found to be 26.5% in cattle, 7.0% in sheep, and 0.0% in horses. Among cattle, the animals up to 3 years old had significantly lower seroprevalence rate than those in older age groups. Natural foci of tick-borne encephalitis are obviously present in northeastern Hungary. On the other hand, no antibodies neutralizing BHAV were detected in the domestic animals.

Mosquitoborne viruses, Czech Republic, 2002.

Specimens from residents (N = 497) of an area affected by the 2002 flood were examined serologically for mosquitoborne viruses. Antibodies were detected against Tahyna (16%), Sindbis (1%), and Batai (0.2%) viruses, but not West Nile virus. An examination of paired serum samples showed 1 Tahyna bunyavirus (California group) infection.

Prevalence of borreliae in ixodid ticks from a floodplain forest ecosystem.

Host-seeking ixodid ticks were sampled in a floodplain forest ecosystem along the lower reaches of the Thaya (Dyje) river in South Moravia (Czech Republic) and Lower Austria during the period 1989-2002. The ticks were examined by dark-field microscopy for borreliae (Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis), and attempts were made to culture the spirochetes in BSK-H medium from preparations containing their high numbers. Isolated borreliae were identified by PCR-RFLP analysis using probes directed against ribosomal spacer genes. A total of 797 nymphal and 719 adult (391 female, 328 male) Ixodes ricinus were examined: 16.2% of nymphs, 28.6% of females and 29.0% of males were positive. Dermacentor reticulatus (70 females, 30 males) and Haemaphysalis concinna (12 nymphs, 8 females, 2 males) were negative for spirochetes. The overall prevalence rate of borreliae in I. ricinus from the floodplain forest is slightly higher than the mean European data (i.e., 14% for nymphs, 21% for adults). The difference in infection rate between nymphal and adult ticks was significant, including the proportion of heavily infected (with > 100 borreliae) nymphs (2.1%) vs. adults (7.6%). Prevalence of borreliae in I. ricinus showed a significant decrease during autumn in this ecosystem. Three strains of spirochetes, all of the Borrelia afzelii genomic group, were isolated from female I. ricinus. Moreover, Trypanosoma/Crithidia sp. protozoa and Dipetalonema rugosicauda nematodes were detected in 0.4% and 1.0%, respectively, of all I. ricinus.

Host-seeking activity of ixodid ticks in relation to weather variables.

Ixodid ticks were monitored in a temperate deciduous broad-leaved forest in South Moravia (Czech Republic). Relative abundance of the ticks collected before noon (10.00-12.00 h) was compared to several weather variables (air and soil temperatures, relative humidity, precipitation, wind speed, and derived values) using the Pearson correlation coefficient. The tick numbers were found to be most closely related to the amplitude of the soil (-5 cm) temperature between 07 h and 14 h (TSamp, in Ixodes ricinus), and the soil temperature (TS) at noon (in Haemaphysalis concinna) or in the morning (Dermacentor reticulatus). While a growing amplitude in TSamp caused an increased host-seeking activity of I. ricinus and H. concinna, it suppressed the activity of D. reticulatus, a tick species mainly occurring in colder seasons of the year in Central Europe. The air temperature (TA) and relative humidity (RH) were also closely related to the tick activity, whereas rainfall and wind speed remained largely uncorrelated with the activity of the three tick species. Multiple linear regression on several variables (TSamp, TA, TS, TA-TS, RH) explained 48% of the variance in I. ricinus, 47% in H. concinna, and 38% in D. reticulatus. Predictive two-variable regression models of relative abundance in host-seeking ticks were based on morning temperature (TA or TS) and morning RH as the most important environmental factors: they explained 32% (I. ricinus), 39% (H. concinna), and 35% (D. reticulatus) of the variance.