Zubrikova et al.
Prevalence of tick-borne encephalitis virus and Borrelia burgdorferi sensu lato in Ixodes ricinus in Lower Bavaria and Upper Palatinate, Germany
Ticks Tick Borne Dis. 2020, in press, doi.org/10.1016/j.ttbdis.2020.101375
Most TBE cases in Germany are consistently reported by the Federal States of Bavaria and Baden-Wuerttemberg, where 2671 and 2702 cases respectively occurred from 2001 to 2018. In the two regions of Bavaria, Upper Palatinate and Lower Bavaria (adjacent to Bohemia, Czech Republic) 569 cases and 455 cases respectively have been recorded from 2001 to 2018 with an incidence of more than 2 per 100,000 inhabitants. In 16 high-risk areas and 4 low-risk areas a total of 8805 Ixodes ricinus ticks were collected and analyzed for infection with TBE virus and 3969 ticks were analyzed for Borrelia burgdorferi s.l.
From the 16 high-risk areas, 7224 ticks in 843 pools were analyzed, and 23 pools were positive for the TBE virus (minimal infection rate: 0.32%). In the low-risk areas, no TBE virus could be detected in 186 pools comprising 1581 ticks. TBE virus prevalence was significantly higher at the high-risk compared to the low-risk sites. Interestingly, TBE virus infected ticks could also be found in a park in the city of Passau. Here, the prevalence of Borrelia sp. in ticks was 29.5%. Overall, mixed infections were identified in 13.6% of ticks and B. afzelii was the most abundant Borrelia species (41.3%), followed by B. garinii (19%), B. valaisiana (13.8%), B. burgdorferi s.s. (11.1%), Candidatus B. finlandensis (0.6%), B. spielmanii (0.4%), and B. lusitaniae (0.2%).