Monitoring the prevalence of pathogenic Borrelia burgdorferi sensu lato in ticks in two Brno locations

OBJECTIVE: The aim of the article is to present the results of monitoring the prevalence of the spirochete Borrelia burgdorferi sensu lato (Bbsl) in Ixodes ricinus ticks in two different locations in the city of Brno, Pisarky and Zamilovaný hajek (ZH). At the same time, factors potentially affecting the activity of ticks in these locations were studied. Results of the monitoring carried out in the first three spring months of the year 2011 are compared with 2010 results. MATERIAL AND METHODS: In 2010-2011, Ixodes ricinus ticks were periodically sampled in two locations in Brno by flagging. Ticks were investigated by dark field microscopy (DFM) for the presence of spirochetes. DFM-positive samples from 2010 were tested by PCR to identify Bbsl. RESULTS: In the first three spring months (March-May) of 2011, a total of 234 ticks were collected in Pisarky and 211 ticks in ZH. Positive samples detected by DFM accounted for 5.56 % in Pisarky and 25.12 % in ZH. PCR confirmed Bbsl in at least 75 %. Statistical analysis confirmed the dependence of tick activity on the air temperature in both locations. CONCLUSION: Within the same city, seroprevalence was found to be different in two locations. High seroprevalence in ZH (25.12 %) could be attributed to focal spread of the disease from several sources, both ticks and reservoirs such as rodents. This may results in unfavourable epidemiological situation in Brno. On the other hand, the seroprevalence rates in Pisarky are consistent with findings from an earlier long-term study.