Browsing by Person "Springer, Andrea"

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Molting incidents of Hyalomma spp. carrying human pathogens in Germany under different weather conditions
(2024) Chitimia-Dobler, Lidia; Springer, Andrea; Lang, Daniel; Lindau, Alexander; Fachet, Katrin; Dobler, Gerhard; Nijhof, Ard M.; Strube, Christina; Mackenstedt, Ute
Background: Hyalomma marginatum and H. rufipes are two-host tick species, which are mainly distributed in southern Europe, Africa to central Asia but may also be found in Central and Northern Europe through introduction by migratory birds. Methods: Ticks were collected while feeding or crawling on animals and humans, or from the environment, in different regions in Germany, between 2019 and 2021 in a citizen science study and from 2022 to 2023 in the wake of this study. Results: From 2019 to 2023, a total of 212 Hyalomma adult ticks were detected in Germany. This included 132 H. marginatum and 43 H. rufipes ticks sent to research institutions and 37 photographic records that were only identified to genus level. The number of detected ticks varied over the years, with the highest number of 119 specimens recorded in 2019, followed by 57 in 2020. Most of the specimens were collected from horses, while some were collected from other animals, humans or found crawling on human clothes or other objects inside or outside houses. The screening of 175 specimens for Crimean-Congo hemorrhagic fever virus and of 132 specimens for Babesia/Theileria spp. by PCR gave negative results, while human-pathogenic Rickettsia were detected in 44% (77/175) of the total samples. Subsequent amplicon sequencing and phylogenetic analysis of representative samples determined the species of 41 Rickettsia aeschlimannii and one R. slovaca sequences. Conclusions: Analysis of climatic factors indicated a significantly higher probability of Hyalomma occurrence at locations with higher average spring temperature during the years 2019 and 2020 compared to randomly generated pseudo-absence locations. Dry and hot conditions probably facilitated Hyalomma nymphs’ survival and molting into adults during these yea
Tick hazard in a Central European country: Mapping Europe’s principal tick-borne disease vector across Germany
(2025) Springer, Andrea; Lindau, Alexander; Fachet-Lehmann, Katrin; Kämmer, Daniel; Bulling, Ingrid; Knoll, Steffen; Król, Nina; Fischer, Dominik; Fischer, Luisa; Drehmann, Marco; Chitimia-Dobler, Lidia; Noll, Madeleine; Vineer, Hannah Rose; Kahl, Olaf; Pfeffer, Martin; Strube, Christina; Mackenstedt, Ute
The most common European tick species, Ixodes ricinus, is the principal vector of Borrelia and tick-borne encephalitis virus and several other pathogens of public health relevance in Europe. Comprehensive data on tick abundance and the underlying ecological drivers are crucial for developing awareness and control strategies and to assess future changes in tick-borne disease risk. We aimed to provide a Germany-wide map of I. ricinus abundance to aid in disease transmission risk assessment. During 2018−2020, questing tick density was assessed at 83 sites across the whole country by drag flagging, whereby 49,344 I. ricinus nymphs and adults were collected. Relationships between climate, land cover, and monthly questing I. ricinus nymph density were explored and used to draw an abundance map. Highest tick hazard was observed in areas near the coast with mild winters and moist springs, and in mid-elevation mountain ranges, which represent popular tourist destinations. The ticks’ seasonal activity pattern was predominantly unimodal. The fact that the observed regional differences are contradictory to a previous estimation based on a combination of regional studies illustrates the need for an extensive and coordinated sampling effort to reliably estimate tick abundance at larger spatial scales. Combined with data on tick-borne pathogens, our study enables estimating the density of infected ticks and consequently the risk of acquiring an infectious tick bite. Moreover, the observed relationships with climate and land cover can help to predict future developments of tick hazard under different climate scenarios in Central Europe.
Tick populations from endemic and non-endemic areas in Germany show differential susceptibility to TBEV
(2020) Liebig, Katrin; Boelke, Mathias; Grund, Domenic; Schicht, Sabine; Springer, Andrea; Strube, Christina; Chitimia-Dobler, Lidia; Dobler, Gerhard; Jung, Klaus; Becker, Stefanie
Tick-borne encephalitis virus (TBEV) is endemic in twenty-seven European countries, transmitted via the bite of an infected tick. TBEV is the causative agent of one of the most important viral diseases of the central nervous system (CNS). In Germany, 890 human cases were registered between the years 2018–2019. The castor bean tick, Ixodes ricinus, is the TBEV vector with the highest importance in Central Europe, including Germany. Despite the nationwide distribution of this tick species, risk areas of TBEV are largely located in Southern Germany. To increase our understanding of TBEV-tick interactions, we collected ticks from different areas within Germany (Haselmühl/Bavaria, Hanover/Lower Saxony) and infected them via an in vitro feeding system. A TBEV isolate was obtained from an endemic focus in Haselmühl. In two experimental series conducted in 2018 and 2019, ticks sampled in Haselmühl (TBEV focus) showed higher artificial feeding rates, as well as higher TBEV infections rates than ticks from the non-endemic area (Hanover). Other than the tick origin, year and month of the infection experiment as well as co-infection with Borrelia spp., had a significant impact on TBEV Haselmühl infection rates. Taken together, these findings suggest that a specific adaptation of the tick populations to their respective TBEV virus isolates or vice versa, leads to higher TBEV infection rates in those ticks. Furthermore, co-infection with other tick-borne pathogens such as Borrelia spp. can lower TBEV infection rates in specific populations.
Update and prognosis of Dermacentor distribution in Germany: Nationwide occurrence of Dermacentor reticulatus
(2022) Springer, Andrea; Lindau, Alexander; Probst, Julia; Drehmann, Marco; Fachet, Katrin; Thoma, Dorothea; Rose Vineer, H.; Noll, Madeleine; Dobler, Gerhard; Mackenstedt, Ute; Strube, Christina
A considerable range expansion of Dermacentor reticulatus has been observed in several European countries, which is concerning in the light of its vector function for several pathogens, including Babesia canis and tick-borne encephalitis virus (TBEV). The present study provides an update on the distribution of Dermacentor ticks in Germany, using a citizen science approach. Ticks were collected by citizens from March 2020 to May 2021, and submitted along with information on the date and location of collection, potential hosts and details about the circumstances of discovery. In total, 3,292 Dermacentor specimens were received, of which 76.4% (2,515/3,292) were identified as D. reticulatus and 23.0% (758/3,292) as D. marginatus, while 0.6% (19/3,292) were too damaged for species-level identification. Dermacentor reticulatus was received from all federal states of Germany. Maxent species distribution models predicted suitable environmental conditions for D. reticulatus throughout Germany. Findings on the vegetation or on pastured animals without travel history confirmed the occurrence of this tick species as far north as the most northern German federal state Schleswig-Holstein. In contrast, the distribution of D. marginatus still appears to be limited to southwestern Germany, although the northward shift of the distribution limit observed in the preceding citizen science study, as compared with previous published distributions, was confirmed. This shift was also predicted by Maxent species distribution models, reflecting the broader distribution of the tick occurrence data contributed by citizens. Most D. reticulatus ticks were found on dogs (1,311/1,960, 66.9%), while D. marginatus was mainly discovered on hoofed animals (197/621, 31.7%) and humans (182/621, 29.3%). Human tick bites were reported in 0.7% (14/1,960) of host-assigned D. reticulatus and 3.4% (21/621) of host-assigned D. marginatus. Further studies to investigate an increasing endemisation of Babesia canis in Germany as well as the relevance of D. reticulatus for TBEV spread throughout the country, e.g., by traveling dogs, are urgently needed. In view of the activity of D. reticulatus during winter or the colder months, which complements that of Ixodes ricinus, a year-round tick protection of at least dogs is strongly recommended.