Exotic ticks removed from German travelers.

We report the finding of five nymphs and three adult ticks attached to German tourists while traveling the American continents. All eight specimens were morphologically identified and confirmed genetically using the 16S rRNA gene and screened for Rickettsia spp. infections. Five tick species were identified: one Amblyomma mixtum nymph from Ecuador, one Amblyomma varium nymph from Colombia, three Amblyomma coelebs nymphs from Costa Rica, one Amblyomma americanum male from the USA, one Dermacentor andersoni female and one D. andersoni male from Canada. Tick-borne microorganisms screening using the pan-Rickettsia-PCR resulted in two positive and six negative ticks. The A. mixtum nymph was positive for Rickettsia amblyommatis, while the D. andersoni female was positive for Rickettsia peacockii.

Ixodes frontalis: a neglected but ubiquitous tick species in Germany.

The ornithophilic tick species Ixodes frontalis (Panzer) is spatially distributed in Europe, Asia and northern Africa. It can serve as a carrier of different bacteria and viruses, but little is known of its actual vector competence. In addition, adult females of this species are associated with the avian "tick-related syndrome" (TRS). Like most ornithophilic tick species, I. frontalis is usually collected from bird nests or directly from their hosts. Reports of I. frontalis being collected with the flagging method are scarce. In Germany, the species is considered as very rare. In the few reports that are available, the majority of ticks has been discovered on migrating birds. Therefore, knowledge of the actual distribution of this species in Germany was strictly limited. In this study, we report the finding of 1084 individuals of I. frontalis collected with the flagging method in urban areas and gardens in several regions of Germany. Furthermore, the species was discovered on 35 dead Eurasian blackbirds (Turdus merula) from all over Germany. Finally, we report of five new possible cases of TRS, three in free-ranging birds and two in captive birds, including a Harris's hawk (Parabuteo unicinctus) kept for falconry.

Carrion crows (Corvus corone) of southwest Germany: important hosts for haemosporidian parasites.

BACKGROUND: Avian malaria parasites (Plasmodium spp.) and other Haemosporida (Haemoproteus and Leucocytozoon spp.) form a diverse group of vector-transmitted blood parasites that are abundant in many bird families. Recent studies have suggested that corvids may be an important host for Plasmodium spp. and Leucocytozoon spp. METHODS: To investigate the diversity of Haemosporida of resident carrion crows (Corvus corone) and Eurasian Magpies (Pica pica) in southwest Germany, 100 liver samples of corvids were examined using a nested PCR method to amplify a 1063 bp fragment of the haemosporidian mitochondrial cytochrome b gene. The phylogenetic relationship of parasite lineages obtained from these birds was inferred. RESULTS: Haemosporidian DNA was detected in 85 carrion crows (89.5%) and in all five Eurasian Magpies. The most abundant parasite genus was Leucocytozoon with a prevalence of 85.3% (n = 95). 65.3% of the samples (n = 62) contained multiple infections. Thirteen haemosporidian lineages were isolated from the corvid samples. Female carrion crows were more likely infected with haemosporidian parasites than males. DISCUSSION: This study provides the first insight into the diversity of haemosporidian parasites of corvids in Germany. Very high prevalences were found and based on the applied diagnostic method also a high amount of multiple infections could be detected. Due to the high diversity of haemosporidian parasites found in corvids, they seem to be excellent model organisms to test species deliminations in haemosporidian parasites.

Germany-wide citizen science study reveals spread of Babesia canis-infected Dermacentor reticulatus ticks by dogs travelling within the country.

The ornate dog tick Dermacentor reticulatus, vector of Babesia canis, has shown a considerable range expansion in several European countries. Previously, only few areas in Germany were recognised as endemic for B. canis, but a marked increase in autochthonous canine babesiosis cases and spread to new areas has been noted recently. To better assess the current risk for dogs, the present study screened 5913 specimens of D. reticulatus from all over Germany, collected in the frame of a Citizen Science study during 2019-2023. Moreover, 343 Dermacentor marginatus ticks were also included. Babesia detection was achieved by quantitative real-time PCR (qPCR). Positive samples were confirmed by sequencing. Moreover, a MGB-probe-based triplex qPCR was established to detect and distinguish between the canine Babesia spp. relevant in Europe, i.e. B. canis, Babesia vogeli and Babesia gibsoni. Overall, B. canis DNA was detected in five D. reticulatus specimens (0.08%). Two of the B. canis-positive ticks originated from areas previously known as endemic for canine babesiosis, namely from the area of Freiburg im Breisgau, federal state of Baden-Wuerttemberg, and from the district St. Wendel, federal state of Saarland. Three further B. canis-positive ticks were detected in districts not yet recognised as endemic, one each in the district of Mansfeld-Suedharz, federal state of Saxony-Anhalt, the district of Ravensburg, federal state of Baden-Wuerttemberg and in the city of Fürth, federal state of Bavaria. However, the tick in Fürth was found on a dog who had returned from a trip to the Breisgau region on the previous day, indicating translocation of the specimen out of this well-known endemic focus. The geographical distribution of the positive samples shows that B. canis is currently spreading in Germany, particularly via dogs travelling within the country, increasing the infection risk throughout the country. Important measures to contain a further spread of the pathogen include comprehensive year-round tick prophylaxis with licensed acaricides, not only to protect the individual pet, but also the entire dog population. Moreover, screening of dogs entering Germany from B. canis-endemic countries is required and any treatment should aim at pathogen elimination by use of appropriate imidocarb dosages.

Molting incidents of Hyalomma spp. carrying human pathogens in Germany under different weather conditions.

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 years.

Update and prognosis of Dermacentor distribution in Germany: Nationwide occurrence of Dermacentor reticulatus.

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.

The Spatial Distribution of Dermacentor Ticks (Ixodidae) in Germany-Evidence of a Continuing Spread of Dermacentor reticulatus.

In Europe, two tick species of the genus Dermacentor occur, Dermacentor marginatus and Dermacentor reticulatus. When the spatial distribution of both species in Germany was studied comprehensively for the first time in 1976, D. marginatus populations were recorded along the Rhine and Main river valleys in southwestern Germany, while D. reticulatus was very rare. In the last 50 years, however, a considerable range expansion of D. reticulatus has been noted in several European countries. To assess the current distribution of Dermacentor spp. in Germany, citizens were asked to send in ticks suspected to belong to the genus Dermacentor or that were of "unusual" appearance. From February 2019 until February 2020, 3,902 Dermacentor ticks were received in total. Of those, 15.48% (604/3,902) were identified as D. marginatus and 84.24% (3,287/3,902) as D. reticulatus, while 11 specimens could not be identified to species level. The majority of D. reticulatus specimens was collected from dogs (1,212/2,535; 47.12%), while D. marginatus was mostly collected from horses (184/526; 34.98%). Our results confirm that the adults of both Dermacentor species are active all year round. D. reticulatus specimens were sent in from all federal states except the Free and Hanseatic City of Hamburg, while D. marginatus specimens were only received from locations in southwestern Germany. Overall, data obtained from this citizen-science study show that D. reticulatus has significantly expanded its range, especially in northern Germany. Regarding D. marginatus, new locations northwest of the previous range were detected, although the distribution has remained rather stable as compared to D. reticulatus. The spread of D. reticulatus, the vector of Babesia canis, is of major importance for veterinarians and dog owners in terms of canine babesiosis outbreaks or endemization in hitherto B. canis-free areas. Thus, veterinarians and veterinary students need to be informed about the new situation to be able to give adequate advice to dog owners on the extended D. reticulatus range and appropriate control measures.