Transstadial Transmission and Replication Kinetics of West Nile Virus Lineage 1 in Laboratory Reared Ixodes ricinus Ticks

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

Zoonotic pathogen screening of striped field mice (Apodemus agrarius) from Austria

The striped field mouse (Apodemus agrarius) is known to carry several zoonotic pathogens, including Leptospira spp. and Dobrava-Belgrade orthohantavirus (DOBV). Since its first detection in 1996 in south-east Austria, the striped field mouse has further expanded its range in Austria. Here, we screened 35 striped field mice collected in an Austrian region near the Hungarian border for DOBV, Leptospira spp. and seven vector-borne pathogens. Hantavirus RT-PCR screening and DOBV IgG ELISA analysis led to the detection of two DOBV-positive striped field mice. The complete coding sequences of all three genome segments of both strains were determined by a combination of target enrichment and next-generation sequencing. Both complete coding S segment sequences clustered within the DOBV genotype Kurkino clade with the highest similarity to a sequence from Hungary. In one of 35 striped field mice, Leptospira borgpetersenii sequence type (ST) 146 was detected. Bartonella spp., Borrelia miyamotoi and Neoehrlichia mikurensis DNA was detected in four, one and two of 32 mice, respectively. Babesia, Anaplasma, Ehrlichia and Rickettsia specific DNA was not detected. Future investigations will have to determine the prevalence and invasion of these pathogens with the ongoing range expansion of the striped field mouse in Austria

Zoonotic pathogen screening of striped field mice (Apodemus agrarius) from Austria

The striped field mouse (Apodemus agrarius) is known to carry several zoonotic pathogens, including Leptospira spp. and Dobrava–Belgrade orthohantavirus (DOBV). Since its first detection in 1996 in south-east Austria, the striped field mouse has further expanded its range in Austria. Here, we screened 35 striped field mice collected in an Austrian region near the Hungarian border for DOBV, Leptospira spp. and seven vector-borne pathogens. Hantavirus RT-PCR screening and DOBV IgG ELISA analysis led to the detection of two DOBV-positive striped field mice. The complete coding sequences of all three genome segments of both strains were determined by a combination of target enrichment and next-generation sequencing. Both complete coding S segment sequences clustered within the DOBV genotype Kurkino clade with the highest similarity to a sequence from Hungary. In one of 35 striped field mice, Leptospira borgpetersenii sequence type (ST) 146 was detected. Bartonella spp., Borrelia miyamotoi and Neoehrlichia mikurensis DNA was detected in four, one and t wo of 32 mice, respectively. Babesia, Anaplasma, Ehrlichia and Rickettsia specific DNA was not detected. Future investigations will have to determine the prevalence and invasion of these pathogens with the ongoing range expansion of the striped field mouse in Austria

Epidemiology and genotyping of Anaplasma marginale and co-infection with piroplasms and other Anaplasmataceae in cattle and buffaloes from Egypt

Background: Anaplasma marginate is an obligate intracellular bacterium and the main cause of bovine anaplasmosis in tropical and subtropical regions. In Egypt, data regarding the prevalence of A. marginate in ruminant hosts and of the circulating genotypes is lacking. This study therefore aimed to (i) investigate the presence, epidemiology and genotypes of A. marginate in cattle and buffaloes in Egypt, (ii) to evaluate suitable diagnostic tools and (iii) to identify co-infections of A. marginate with 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 of A. marginate infection, 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 with A. marginate, piroplasms and other Anaplasmataceae were surveyed by RLB while A. marginate genotypes were identified by amplifying and sequencing the partial mspla gene. Results: Anaplasma marginate DNA was amplified by qPCR in 68.3% of cattle and 29.4% of buffaloes. RLB showed infection with A. marginale in 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 against A. marginate in 54.9% of cattle. Anaplasma marginate was associated, in cattle and buffaloes, with several tick-borne pathogens (Theileria annulata, Babesia bovis, Babesia bigemina, Babesia occultans and Anaplasma platys). A significant difference of A. marginale infection 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 of A. marginate in cattle and buffaloes in all the investigated areas. The circulation of diverse genotypes was observed, most of these A. marginate genotypes being specific for Egypt. The qPCR assay was confirmed to be the most sensitive tool for detection of A. marginate in cattle and buffaloes even in the carrier state, highlighting the importance of using suitable diagnostic tests

Anaplasma phagocytophilum and Anaplasma ovis–Emerging Pathogens in the German Sheep Population

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

Prevalence and molecular characterization of ticks and tick-borne pathogens of one-humped camels (Camelus dromedarius) in Nigeria

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