ABSTRACT
A total of 691 Ixodes ricinus (22 male, 39 female, 501 nymphs and 129 larvae), the tick vector of Lyme borreliosis, were collected by flagging from vegetation in 11 areas at altitudes between 789 m and 1350 m above sea level in mixed woodland with pasture land (cattle) in the province of Styria in Austria. The ticks were individually examined for presence of Borrelia burgdorferi sensu lato by dark-field microscopy and 107 of them by real-time PCR. Attempts to cultivate borreliae were made in BSK-H medium. The overall positivity rate of all collected ticks (excepting larvae) was 10.9%: 9.1% in males, 17.9% in females and 10.4% in nymphs. The 129 larvae examined showed no presence of B. burgdorferi s.l. The mean infection rate of I. ricinus collected at the highest altitude in this study, Gaberl at 1350 m a.s.l.--and at the same time the highest one reported in Europe--was 6.4%: 1/9 males, 2/18 females and 6/114 (5.3%) nymphs were positive. Culture attempts were positive in 12 cases and species identification showed eight isolates were B. afzelii and four B. garinii. Three additional positive results found by PCR (negative by culture) were identified twice as B. afzelii and once as B. garinii. This study shows that the risk of acquiring Lyme borreliosis in habitats at higher altitudes is limited, because of the lower density of I. ricinus and its lesser infection rate than at lower altitudes in central Europe, but nevertheless the risk does exist.
Subject(s)
Borrelia burgdorferi/isolation & purification , Ixodes/microbiology , Animals , Austria , Female , Larva/microbiology , Male , Microscopy , Nymph/microbiology , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Prevalence , Risk Factors , Sex FactorsSubject(s)
Antidiarrheals/therapeutic use , Diarrhea/therapy , Travel , Antidiarrheals/adverse effects , Austria/epidemiology , Female , Fluid Therapy , Humans , Loperamide/adverse effects , Loperamide/therapeutic use , Male , Practice Guidelines as Topic , Self Medication/statistics & numerical data , Surveys and QuestionnairesABSTRACT
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.
