Oliver Tauchmann

Background: Ixodid ticks from the Northern Hemisphere have registered a northward expansion in recent years, and Dermacentor reticulatus is such an example in Europe, its expansion being considered a result of climate change alongside other factors. The aim of this study was to identify the composition of questing tick species and the associated pathogens at different sites near the German Baltic coast. Methods: Questing ticks were collected monthly at four sites (May–November, 2020), mainly grasslands, and in October and November 2020 at a fifth site. Molecular screening of ticks for pathogens included RT-qPCR for the tick-borne encephalitis virus (TBEV), qPCR for Anaplasma phagocytophilum, PCR for Babesia species and Rickettsia species, and nested PCR for Borrelia species. Results: Altogether 1174 questing ticks were collected: 760 Ixodes ricinus, 326 D. reticulatus and 88 Haemaphysalis concinna. The highest activity peak of I. ricinus and D. reticulatus was in May, in June for H. concinna while a second peak was observed only for I. ricinus and D. reticulatus in September and October, respectively. All samples tested negative for TBEV. For A. phagocytophilum, 1.5% of I. ricinus adults tested positive while the minimum infection rate (MIR) in nymphs was 1.3%. This pathogen was found in 0.6% of D. reticulatus. Babesia spp. were detected in I. ricinus (18.2% adults, 2.1% MIR in nymphs) and H. concinna (13.3% adults, 9.7% MIR in nymphs). Borrelia spp. were present only in I. ricinus (49.1% adults, 11.9% MIR in nymphs), while Rickettsia spp. were detected in I. ricinus (14% adults, 8.9% MIR in nymphs) and D. reticulatus (82%). Co-detection of pathogens was observed in 26.6% and 54.8% of positive I. ricinus adults and nymph pools, respectively, while one D. reticulatus tested positive for A. phagocytophilum and Rickettsia spp. The most common co-infection in I. ricinus adults was Babesia microti and Borrelia afzelii (12.3% of positive ticks). Conclusions: The results of this study confirm the northern expansion of D. reticulatus and H. concinna in Germany. The detailed data of the infection levels at each location could be useful in assessing the risk of pathogen acquisition following a tick bite. Graphical

Knowledge on the occurrence of pathogenic tick-borne bacteria Anaplasma phagocytophilum and Anaplasma ovis is scarce in sheep from Germany. In 2020, owners from five flocks reported ill thrift lambs and ewes with tick infestation. Out of 67 affected sheep, 55 animals were clinically examined and hematological values, blood chemistry and fecal examinations were performed to investigate the underlying disease causes. Serological tests (cELISA, IFAT) and qPCR were applied to all affected sheep to rule out A. phagocytophilum and A. ovis as a differential diagnosis. Ticks were collected from selected pastures and tested by qPCR. Most animals (n = 43) suffered from selenium deficiency and endoparasites were detected in each flock. Anaplasma spp. antibodies were determined in 59% of examined sheep. Seventeen animals tested positive for A. phagocytophilum by qPCR from all flocks and A. phagocytophilum was also detected in eight pools of Ixodes ricinus. Anaplasma phagocytophilum isolates from sheep and ticks were genotyped using three genes (16S rRNA, msp4 and groEL). Anaplasma ovis DNA was identified in six animals from one flock. Clinical, hematological and biochemical changes were not significantly associated with Anaplasma spp. infection. The 16S rRNA analysis revealed known variants of A. phagocytophilum, whereas the msp4 and groEL showed new genotypes. Further investigations are necessary to evaluate the dissemination and health impact of both pathogens in the German sheep population particularly in case of comorbidities.

Background: Anaplasma marginaleis an obligate intracellular bacterium and the main cause of bovine anaplasmosis in tropical and subtropical regions. In Egypt, data regarding the prevalence ofA. marginalein ruminant hosts and of the circulating genotypes is lacking. This study therefore aimed to (i) investigate the presence, epidemiology and genotypes ofA. marginalein cattle and buffaloes in Egypt, (ii) to evaluate suitable diagnostic tools and (iii) to identify co-infections ofA. marginalewith other selected tick-borne pathogens.Methods: Blood samples were collected from 394 animals (309 cattle and 85 buffaloes) from three different areas in Egypt. For the detection ofA. marginaleinfection, several tests were compared for their sensitivity and specificity: blood smear analysis, enzyme-linked immunosorbent assay (ELISA), PCR, real-time PCR and reverse line blot (RLB) assay. Co-infections withA. marginale,piroplasms and otherAnaplasmataceaewere surveyed by RLB whileA. marginalegenotypes were identified by amplifying and sequencing the partialmsp1αgene.Results: Anaplasma marginaleDNA was amplified by qPCR in 68.3% of cattle and 29.4% of buffaloes. RLB showed infection withA. marginalein 50.2% of cattle and 42.5% of buffaloes. Blood smear analysis detected this agent in 16.2% of cattle and 2.4% of buffaloes. ELISA showed specific antibodies againstA. marginalein 54.9% of cattle.Anaplasma marginalewas associated, in cattle and buffaloes, with several tick-borne pathogens (Theileria annulata,Babesia bovis,Babesia bigemina,Babesia occultansandAnaplasma platys). A significant difference ofA. marginaleinfection level was noticed in cattle, where animals between 3–5-years-old had a higher prevalence (79.2%) compared to those older than 5 years (36.4%) and younger than 3 years (59.7%) and one year (64.5%), respectively (P = 0.002281). Microsatellite analysis identified 15 different genotypes.Conclusions: The epidemiological findings revealed high prevalence ofA. marginalein cattle and buffaloes in all the investigated areas. The circulation of diverse genotypes was observed, most of theseA. marginalegenotypes being specific for Egypt. The qPCR assay was confirmed to be the most sensitive tool for detection ofA. marginalein cattle and buffaloes even in the carrier state, highlighting the importance of using suitable diagnostic tests.

West Nile virus (WNV) is a mosquito-borne agent that has also been isolated from several tick species. Vector competence of Ixodes ricinus, one of the most common tick species in Europe, has been poorly investigated for WNV to date. As such, to evaluate the vector competence, laboratory reared Ixodes ricinus nymphs were in vitro fed with WNV lineage 1 infectious blood, allowed to molt, and the resulting females artificially fed to study the virus transmission. Furthermore, we studied the kinetics of WNV replication in ticks after infecting nymphs using an automatic injector. Active replication of WNV was detected in injected nymphs from day 7 post-infection until 28 dpi. In the nymphs infected by artificial feeding, the transstadial transmission of WNV was confirmed molecularly in 46.7% of males, while virus transmission during in vitro feeding of I. ricinus females originating from infected nymphs was not registered. The long persistence of WNV in I. ricinus ticks did not correlate with the transmission of the virus and it is unlikely that I. ricinus represents a competent vector. However, there is a potential reservoir role that this tick species can play, with hosts potentially acquiring the viral agent after ingesting the infected ticks.

Background: Ticks are hematophagous arthropods responsible for maintenance and transmission of several pathogens of veterinary and medical importance. Current knowledge on species diversity and pathogens transmitted by ticks infesting camels in Nigeria is limited. Therefore, the aim of this study was to unravel the status of ticks and tick-borne pathogens of camels in Nigeria. Methods: Blood samples (n = 176) and adult ticks (n = 593) were collected from one-humped camels (Camelus dromedarius) of both sexes in three locations (Kano, Jigawa and Sokoto states) in north-western Nigeria and screened for the presence of Rickettsia spp., Babesia spp., Anaplasma marginale, Anaplasma spp. and Coxiella-like organisms using molecular techniques. All ticks were identified to species level using a combination of morphological and molecular methods. Results: Ticks comprised the three genera Hyalomma, Amblyomma and Rhipicephalus. Hyalomma dromedarii was the most frequently detected tick species (n = 465; 78.4%) while Amblyomma variegatum (n = 1; 0.2%) and Rhipicephalus evertsi evertsi (n = 1; 0.2%) were less frequent. Other tick species included H. truncatum (n = 87; 14.7%), H. rufipes (n = 19; 3.2%), H. impeltatum (n = 18; 3.0%) and H. impressum (n = 2; 0.3%). The minimum infection rates of tick-borne pathogens in 231 tick pools included Rickettsia aeschlimannii (n = 51; 8.6%); Babesia species, (n = 4; 0.7%) comprising of B. occultans (n = 2), B. caballi (n = 1) and Babesia sp. (n = 1); Coxiella burnetii (n = 17; 2.9%); and endosymbionts in ticks (n = 62; 10.5%). We detected DNA of “Candidatus Anaplasma camelli” in 40.3% of the blood samples of camels. Other tick-borne pathogens including Anaplasma marginale were not detected. Analysis of risk factors associated with both tick infestation and infection with Anaplasma spp. in the blood indicated that age and body condition scores of the camels were significant (P < 0.05) risk factors while gender was not. Conclusions: This study reports low to moderate prevalence rates of selected tick-borne pathogens associated with camels and their ticks in north-western Nigeria. The presence of zoonotic R. aeschlimannii emphasizes the need for a concerted tick control programme in Nigeria.

Background: Ixodes ricinusis the most common tick species in Europe and the main vector forBorrelia burgdorferi(sensu lato) and tick-borne encephalitis virus (TBEV). It is involved also in the transmission ofBorrelia miyamotoi, a relapsing fever spirochete that causes health disorders in humans. Little is known regarding the circulation ofBorreliaspecies and the natural foci of TBEV in north-eastern Germany. The goal of this study was to investigate the infection rates ofBorreliaspp. and of TBEV inI. ricinusticks from north-eastern Germany.Methods: Ticks were collected by flagging from 14 forest sites in Mecklenburg-Western Pomerania between April and October 2018. RNA and DNA extraction was performed from individual adult ticks and from pools of 2–10 nymphs. Real time reverse transcription PCR (RT-qPCR) targeted the 3′ non-coding region of TBEV, while DNA ofBorreliaspp. was tested by nested PCR for the amplification of 16S-23S intergenic spacer. Multilocus sequence typing (MLST) was performed onB. miyamotoiisolates.Results: In total, 2407 ticks were collected (239 females, 232 males and 1936 nymphs). Female and maleI. ricinusticks had identical infection rates (both 12.1%) forBorreliaspp., while nymphal pools showed a minimum infection rate (MIR) of 3.3%. Sequencing revealed fourBorreliaspecies:B. afzelii,B. garinii,B. valaisianaandB. miyamotoi.Borrelia afzeliihad the highest prevalence in adult ticks (5.5%) and nymphs (MIR of 1.8%).Borrelia miyamotoiwas identified in 3.0% of adults and registered the MIR of 0.8% in nymphs.Borrelia valaisianawas confirmed in 2.5% adult ticks and nymphs had the MIR of 0.7%, whileB. gariniiwas present in 1.1% of adults and showed a MIR of 0.1% in nymphs. The MLST ofB. miyamotoiisolates showed that they belong to sequence type 635. No tick sample was positive after RT-qPCR for TBEV RNA.Conclusions: The prevalence ofB. miyamotoiinI. ricinusticks registered similar levels to other reports from Europe suggesting that this agent might be well established in the local tick population. The detection ofB. burgdorferi(s.l.) indicates a constant circulation in tick populations from this region.