The potential role of migratory birds in transmission cycles of Babesia spp., Anaplasma phagocytophilum,and Rickettsia spp.

Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp. are potentially emerging tick-borne pathogens, whereas many issues about their ecology, e.g. reservoir host specificity, are still unclear. In spring 2007, we collected 191 feeding Ixodes ricinus ticks from 99 birds of 11 different species on a German bird conservation island in the Baltic Sea. Babesia spp. were detected in 4.7% (9/191), A. phagocytophilum was present in 2.6% (5/191), and Rickettsia spp. were identified in 7.3% (14/191) of the investigated ticks. Further characterization of Babesia spp. infections resulted in B. divergens and B. microti. Among the Rickettsia spp. infections, we identified at least 2 different species: R. monacensis and R. helvetica. Furthermore, 2 ticks harboured mixed infections. Our study provides first interesting insights into the role of migratory birds in the distribution of several emerging tick-borne pathogens.     

Detection of Rickettsia spp. and Anaplasma phagocytophilum in Ixodes ricinus ticks in a region of Middle Germany (Thuringia)

Rickettsia spp. and Anaplasma spp. are regarded as potentially emerging tick-borne pathogens, but so far data on prevalence rates in questing ticks and reports on human diseases in several parts of Europe are rarely available.In this study, 430 nymphs and 570 adult Ixodes (I.) ricinus ticks were collected from a frequently visited forest region of Thuringia (Zeitzgrund, near Stadtroda) in 2006 (n=506) and 2007 (n=494). Individual ticks were investigated for a part of the citrate synthase gene (gltA) of Rickettsia spp. and the 16S rRNA gene of Anaplasma phagocytophilum. Positive amplicons were identified with restriction fragment length polymorphism (RFLP) and/or sequencing. Overall, 14.7% (147/1000) of investigated ticks were infected with Rickettsia spp. After sequencing of 64/147 positive amplicons R. helvetica (29/64) was detected predominantly. Prevalence varied in different developmental stages between 9.3% (40/430) in nymphs and 18.8% (107/570) in adults. A. phagocytophilum-specific DNA was detected in 5.4% (54/1000) of ticks with an infection rate of 4.7% (20/430) in nymphs and 6.0% (34/570) in adults. In 1% (10/1000) of ticks coinfections with Rickettsia spp. and A. phagocytophilum were found. Our study provides interesting insights into the circulation and cocirculation of different rickettsial species and A. phagocytophilum in the same biotope.     

Tick-borne zoonotic pathogens in ticks feeding on the common nightingale including a novel strain of Rickettsia sp.

We examined 77 Ixodes ricinus ticks found on 33 out of 120 common nightingales (Luscinia megarhynchos) sampled in the Czech Republic in 2008 for the presence of Borrelia spirochetes, Anaplasma phagocytophilum, Rickettsia spp., and Babesia spp. We detected Borrelia garinii (in 4% of ticks), A. phagocytophilum (1%), Rickettsia helvetica (3%), a novel strain of Rickettsia sp. (sister taxon of R. bellii; 1%), and Babesia sp. EU1 (1%). Thus, we conclude that nightingales are unlikely to be important reservoir hosts for tick-borne pathogens.     

A 15-year monitoring of Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) in questing ticks in the city of Hanover,Germany

Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) are regarded as potentially emerging tick-borne pathogens and may change in abundance in response to global climate change. However, continuous monitoring on their prevalence in questing ticks is only available for the northern German city of Hanover. In the presented follow-up of this long-term study, 2100 questing ticks of the Ixodes ricinus/Ixodes inopinatus-complex collected from April to October 2020 at ten different recreation sites in Hanover were individually analysed for Rickettsia and A. phagocytophilum infection by quantitative real-time PCR. Together with previous results from years 2005, 2010 and 2015, the current study allows to assess potential changes in tick infection rates with Rickettsiales over a 15-year monitoring period. In 2020, 3.0% (63/2100) of ticks were infected with A. phagocytophilum, 36.0% (756/2100) with Rickettsia spp. and 1.2% (26/2100) with both pathogens. Regarding the different developmental tick stages, nymphs showed a significantly lower A. phagocytophilum prevalence of 0.5% (5/1050) than adult ticks (5.5% [58/1050]) as well as compared to females (5.4% [38/700]) and males (5.7% [20/350]). For Rickettsia spp., nymphs also showed a lower prevalence of 33.2% (349/1050) with a significant difference to adult ticks (38.8% [407/1050]) and female ticks (40.7% [285/700]), while males had a Rickettsia infection rate of 34.9% (122/350). Comparison with previous years indicated a stable A. phagocytophilum prevalence over the 15-year monitoring period. In contrast, fluctuating Rickettsia prevalences were observed, with a peak in 2015 in all developmental stages, but similar infection rates in 2005 and 2020. Therefore, epidemiological changes in response to climate change are not (yet) evident. Nevertheless, the long-term monitoring study will be continued in the future, as climatic impacts on tick and reservoir host populations may have a delayed effect on pathogen prevalence and, consequently, transmission to humans and domestic animals.     

Molecular identification of tick-borne pathogens (Rickettsia spp., Anaplasma phagocytophilum,Borrelia burgdorferi sensu lato,Coxiella burnetii and piroplasms) in questing and feeding hard ticks from North-Western Spain

The occurrence of tick-borne pathogens (TBPs) of human and veterinary interest was studied in questing and feeding ticks collected from wild animals in a region in North-Western Spain. A total of 529 ticks (489 questing, 40 feeding) of seven different species (386 Ixodes ricinus, 53 Haemaphysalis concinna, 27 Haemaphysalis punctata, 25 Dermacentor marginatus, 21 Haemaphysalis inermis, 15 Dermacentor reticulatus, and two Rhipicephalus bursa) were analyzed. Molecular analysis of the 16S rRNA gene in I. ricinus ticks, revealed the presence of two phylogenetic groups in the region. Most of the sequenced ticks (96%) were assigned to I. ricinus haplogroup and 4% of the ticks were phylogenetically related to I. inopinatus haplogroup. Feeding ticks were removed from 17 animals from seven wild species (seven roe deer -Capreolus capreolus-, three wolves -Canis lupus-, two Iberian red deer -Cervus elaphus hispanicus-, two European wild boar -Sus scrofa-, one Cantabrian brown bear -Ursus arctos-, one Eurasian badger -Meles meles-, and one red fox -Vulpes vulpes-). Presence of Rickettsia spp., Anaplasma phagocytophilum, piroplasms, Borrelia burgdorferi sensu lato (s.l.) and Coxiella burnetii were tested in ticks by specific PCR. A total of 92 (17.4%) of the 529 ticks analyzed were positive for at least one of the TBPs tested. Sequencing revealed the presence of the genospecies “Candidatus Rickettsia rioja”, Rickettsia raoultii, and Anaplasma phagocytophilum in both questing and feeding ticks. Rickettsia slovaca, Borrelia lusitaniae, Borrelia afzelii, Borrelia garinii, Borrelia burgdorferi sensu stricto and Babesia bigemina were only detected in questing ticks, while Babesia sp. badger type A, Theileria OT3 and Hepatozoon canis occurred only in engorged ticks. None of the ticks were positive for C. burnetii. The analysis of the 16S rRNA gene sequences of A. phagocytophilum revealed the presence of three variants (I, X and W) circulating in the region. New host-tick-pathogen interactions have been revealed, finding for the first time the human pathogen R. raoultii in D. reticulatus removed from a Cantabrian brown bear. Co-occurrence between different TBPs were detected in 4.3% of the ticks. The association B. burgdorferi s.l./Rickettsia spp. was detected in questing ticks; and Rickettsia spp./piroplasms and A. phagocytophilum/Theileria OT3 in feeding ticks. The presence of pathogenic agents constitutes a threat to human and animal health, and should be considered in the diagnosis and treatment after a tick bite. This study increases the knowledge on TBPs diversity of medical and veterinary interest circulating between ticks and their hosts in North-Western Spain.     

新疆维吾尔自治区夏尔西里自然保护区全沟硬蜱复合感染蜱媒病原研究

目的 了解新疆维吾尔自治区(新疆)夏尔西里自然保护区全沟硬蜱蜱媒病原复合感染情况。方法 2012年6月至2013年6月在新疆夏尔西里自然保护区采用布旗法采集全沟硬蜱,通过巢式PCR方法对蜱体内莱姆病伯氏疏螺旋体[Borrelia(B.) burgdorferi] 5S~23S rRNA 基因间隔区、无形体(Anaplasma)16S rRNA基因、斑点热立克次体(Rickettsia)ompA基因、Q热贝氏柯克斯体Coxiella(C.)burneti的com1基因、巴贝西原虫(Babesia)的Nss-rRNA基因进行扩增。结果 204只全沟硬蜱中104只蜱病原检测阳性,阳性率为50.98%,其中伯氏疏螺旋体阳性率为34.31%(n=70),斑点热立克次体阳性率为28.92%(n=59),嗜吞噬细胞无形体阳性率为9.31%(n=19),未检出Q热贝氏柯克斯体和巴贝西原虫。χ²检验显示,不同病原感染率差异有统计学意义(χ²=38.517,P=0.000)。204只蜱中有39只存在复合感染,复合感染率为19.12%(39/204),在病原检测阳性蜱中复合感染率为37.50%(39/104)。伯氏疏螺旋体与斑点热立克次体复合感染率为16.18%(n=33);伯氏疏螺旋体与嗜吞噬细胞无形体复合感染率为4.90%(n=10),斑点热立克次体与嗜吞噬细胞无形体复合感染率为2.94%(n=6),3种病原体复合感染率为2.45%(n=5)。经χ²检验,3种病原混合感染率差异有统计学意义(χ²=41.328,P=0.000)。结论 新疆夏尔西里自然保护区全沟硬蜱存在伯氏疏螺旋体、嗜吞噬细胞无形体、斑点热立克次体的自然感染,并存在2~3种病原的复合感染。     

Comprehensive screening of tick-borne microorganisms indicates that a great variety of pathogens are circulating between hard ticks (Ixodoidea: Ixodidae) and domestic ruminants in natural foci of Anatolia

Grazing domestic ruminants serve as important reservoirs and/or amplificatory hosts in the ecology of tick-borne pathogens (TBPs) and tick vectors in the natural foci; however, many enzootic life cycles including ruminants and ticks are still unknown. This study investigated a wide range of TBPs circulating among ticks and grazing ruminants in the natural foci of Anatolia, Turkey. Tick specimens (n = 1815) were collected from cattle, sheep, and goats in three ecologically distinct areas (wooded, transitional, and semi-arid zones) of Anatolia and identified by species: Dermacentor marginatus, Dermacentor reticulatus, Hyalomma anatolicum, Hyalomma excavatum, Hyalomma marginatum, Hyalomma scupense, Haemaphysalis inermis, Haemaphysalis parva, Haemaphysalis punctata, Haemaphysalis sulcata, Ixodes ricinus, Rhipicephalus bursa, and Rhipicephalus turanicus. PCR-sequencing analyses revealed TBPs of great diversity, with 32 different agents identified in the ticks: six Babesia spp. (Babesia occultans, Babesia crassa, Babesia microti, Babesia rossi, Babesia sp. tavsan1, and Babesia sp. Ucbas); four Theileria spp., including one putative novel species (Theileria annulata, Theileria orientalis, Theileria ovis, and Theileria sp.); one Hepatozoon sp.; four Anaplasma spp., including one novel genotype (Anaplasma phagocytophilum, Anaplasma marginale, Anaplasma ovis, and Anaplasma sp.); six unnamed Ehrlichia spp. genotypes; Neoehrlichia mikurensis; nine spotted fever group rickettsiae, including one putative novel species (Rickettsia aeschlimannii, Rickettsia slovaca, Rickettsia hoogstraalii, Rickettsia monacensis with strain IRS3, Rickettsia mongolitimonae, Rickettsia raoultii, Candidatus Rickettsia goldwasserii, Candidatus Rickettsia barbariae, and Rickettsia sp.); and Borrelia valaisiana. Detailed phylogenetic analyses showed that some of the detected pathogens represent more than one haplotype, potentially relating to the tick species or the host. Additionally, the presence of Neoehrlichia mikurensis, an emerging pathogen for humans, was reported for the first time in Turkey, expanding its geographical distribution. Consequently, this study describes some previously unknown tick-borne protozoan and bacterial species/genotypes and provides informative epidemiological data on TBPs, which are related to animal and human health, serving the one health concept.     

Detection of tick-borne pathogens in Rhipicephalus sanguineus sensu lato and dogs from different districts of Portugal

Dogs are highly exposed to pathogens transmitted by ectoparasites. The Mediterranean climate of Southern Europe, together with the presence of stray and/or neglected pets in close proximity with humans, contribute for tick expansion and stand for increased risk to infections in humans due to the zoonotic potential of many of these agents.The aim of this study was to perform a molecular survey in dogs (suspected of tick-borne disease and/or infested with ticks), as well as in ticks collected from those animals, from 12 districts of Portugal to investigate the occurrence of Rickettsia spp. and other tick-borne pathogens (Babesia, Ehrlichia, Anaplasma and Hepatozoon). Additionally, a serological survey of spotted fever group Rickettsia in Portuguese dogs was performed using an in-house immunofluorescence assay (IFA).A total of 200 whole-blood samples and 221 Rhipicephalus sanguineus s. l. ticks were collected from dogs.A total of 14 (7 %) blood samples and 10 (4.5 %) ticks yielded presumptively positive 420-bp amplicons using the Rickettsia spp. partial ompB nested PCR. Screening of the ompB-positive samples using the gltA gene showed 8 positive ticks. All Rickettsia ompB and gltA sequences had the highest identity with R. massiliae. The Rickettsia-positive dogs were further tested for other tick-borne pathogens and were found to be infected with Babesia spp. (n = 5), but not with Ehrlichia, Anaplasma or Hepatozoon.Of the 149 dog serum specimens tested in the serological assay, 103 (69 %) were positive for IgG antibodies against spotted fever group Rickettsia. Antibodies were found in dogs from all the studied districts, in 55 (53 %) of the stray and in 48 (47 %) of the owned dogs.Our study detected and characterized for the first time R. massiliae in dogs from Portugal, broadening the geographical range of this canine pathogen and adding knowledge to the impact of this disease in dogs.     

Prevalence of antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato,Babesia gibsoni,and Ehrlichia spp. in dogs in the Republic of Korea

There is a lack of comprehensive studies on the seroprevalence of tick-borne pathogens in the Republic of Korea. Therefore, the aim of this study was to investigate the seroprevalences of Anaplasma spp. (A. phagocytophilum/A. platys), Borrelia burgdorferi sensu lato, Babesia gibsoni, Ehrlichia spp. (E. canis/E. ewingii), and Ehrlichia chaffeensis in dogs across the Republic of Korea in 2017 and 2018. A total of 2215 serum samples collected from 938 companion dogs, 969 shelter dogs, and 308 military working dogs were examined using commercial enzyme-linked immunosorbent assay (ELISA) and indirect fluorescence immunoassay (IFA) kits. Data collected for each animal, including breed, sex, age, region, season, and dog type, were used for statistical analysis. The overall seroprevalence was highest for Anaplasma spp. (15.1 %), followed by Ehrlichia spp. (10.3 %), B. burgdorferi sensu lato (6.4 %), E. chaffeensis (2.3 %), and B. gibsoni (1.7 %). One hundred and sixty-one dogs had antibodies against two or three different pathogens. The most common combinations were Anaplasma spp. - Ehrlichia spp. (2.1 %), Anaplasma spp. - E. chaffeensis (1.4 %), and Anaplasma spp. - B. burgdorferi sensu lato (1.2 %). Season was significantly associated with the seroprevalences of B. burgdorferi sensu lato and Ehrlichia spp., with dogs presenting the highest percentage of positive results during summer. Anaplasma spp. and B. gibsoni were significantly more prevalent in the northern and southern regions, respectively. The seroprevalences of Anaplasma spp., B. burgdorferi sensu lato, and Ehrlichia spp. were significantly higher in military working dogs, while the seroprevalence of E. chaffeensis was higher in companion dogs. The current findings are important for future surveillance of canine tick-borne pathogens and designing appropriate approaches for the diagnosis and control of these pathogens in the Republic of Korea.     

Seroprevalence of Anaplasma spp. and Ehrlichia spp. and molecular detection of Anaplasma phagocytophilum and Anaplasma platys in stray dogs in Bosnia and Herzegovina

Stray dogs may be highly exposed to vector-borne pathogens (VBPs), including zoonotic agents, and therefore may pose a high risk of spreading infections to other animals and humans. Among the Anaplasmataceae, Anaplasma phagocytophilum, A. platys and Ehrlichia canis are commonly identified species in dogs in Europe; however, information on the occurrence of these pathogens in canine populations from Bosnia and Herzegovina (B&H) is still lacking. Thus, the aim of this study was to determine the seroprevalence of Anaplasma spp. and Ehrlichia spp. in stray dogs in the Sarajevo region of B&H and to identify A. phagocytophilum, A. platys, E. canis and E. ewingii by molecular techniques. A total of 903 blood samples of stray dogs were screened by SNAP 4Dx Plus Test for the presence of antibodies against A. phagocytophilum/A. platys and E. canis/E. ewingii. Real-time PCR assays were performed for the detection of Anaplasmataceae, A. phagocytophilum, A. platys, E. canis and E. ewingii in seropositive dogs. Antibodies to A. phagocytophilum/A. platys and/or E. canis/E. ewingii were detected in 187 (20.7%) samples. Seroprevalence was highest for A. phagocytophilum/A. platys (184/903, 20.4%). Two dogs had antibodies to E. canis/E. ewingii, while one dog was found to have antibodies to A. phagocytophilum/A. platys and to E. canis/E. ewingii. Forty-eight (25.7%) of the 187 seropositive dogs examined by Real-time PCR were positive for Anaplasmataceae. A. phagocytophilum was detected in 45 (24%) samples, while one sample was positive for A. phagocytophilum and A. platys. Two samples positive for Anaplasmataceae tested negative in the species-specific PCRs. E. canis or E. ewingii could not be detected in any of the Ehrlichia-seropositive dogs. These findings highlight the need for dog health monitoring, improving the health and welfare of stray dog population, and establishment of effective surveillance systems to combat VBDs.     

15-year Borrelia prevalence and species distribution monitoring in Ixodes ricinus/inopinatus populations in the city of Hanover,Germany

Lyme borreliosis, caused by Borrelia burgdorferi sensu lato (s.l.) spirochaetes, is the most common tick-borne disease (TBD) in the Northern Hemisphere. Rising incidences indicate that its epidemiology may be affected by global changes. Therefore, the current study aimed to assess changes in tick infection rates with Borrelia spp. over a 15-year monitoring period in the city of Hanover, Germany, as a follow-up to previous prevalence studies (years 2005, 2010 and 2015). To assess the epidemiological risk, ticks of the Ixodes ricinus/inopinatus-complex were sampled from April to October 2020 by the flagging method at 10 frequently visited recreation areas in Hanover. Analysis by quantitative real-time PCR of 2100 individual ticks revealed an overall Borrelia prevalence of 25.5% (535/2100). Regarding different tick developmental stages, nymphs showed a significantly lower Borrelia prevalence (18.4% [193/1050]) than adult ticks (32.6% [342/1050]). Comparison with previous years revealed a stable total Borrelia prevalence along with consistent infection rates in the different developmental stages over the 15-year monitoring period. Borrelia species differentiation by Reverse Line Blot was successful in 67.3% of positive ticks collected in 2020, with B. afzelii being the dominating species (59.2% of the differentiated infections), besides B. burgdorferi sensu stricto (s.s.), B. garinii, B. valaisiana, B. spielmanii, B. bavariensis and B. bissettiae and the relapsing fever spirochaete B. miyamotoi. Additionally, the proportion of infections attributed to B. afzelii showed a significant increase in 2020 compared to 2005 and 2015 (59.2% vs. 37.6% and 32.0% of successfully differentiated infections, respectively). Coinfections with Anaplasma phagocytophilum and Rickettsia spp. stayed stable comparing 2020 with previous years. Therefore, although changes in the Borrelia prevalence in questing ticks were not observed throughout the 15-year monitoring period, shifts in Borrelia species distribution may alter the epidemiological risk.     

Presence of diverse Rickettsia spp. and absence of Borrelia burgdorferi sensu lato in ticks in an East Texas forest with reduced tick density associated with controlled burns

As tick-borne diseases continue to emerge across the United States, there is need for a better understanding of the tick and pathogen communities in the southern states and of habitat features that influence transmission risk. We surveyed questing and on-host ticks in pine-dominated forests with various fire management regimes in the Sam Houston National Forest, a popular recreation area near Houston, Texas. Four linear transects were established- two with a history of controlled burns, and two unburned. Systematic drag sampling yielded 112 ticks from two species, Ixodes scapularis (n=73) and Amblyomma americanum (n=39), with an additional 106 questing ticks collected opportunistically from drag cloth operators. There was a significant difference in systematically-collected questing tick density between unburned (15 and 18 ticks/1000 m²) and burned (2 and 4 ticks/1000 m²) transects. We captured 106 rodents and found 74 ticks on the rodents, predominantly Dermacentor variabilis. One unburned transect had significantly more ticks per mammal than any of the other three transects. DNA of Rickettsia species was detected in 146/292 on and off-host ticks, including the ‘Rickettsial endosymbiont of I. scapularis’ and Rickettsia amblyommatis, which are of uncertain pathogenicity to humans. Borrelia lonestari was detected in one A. americanum, while Borrelia burgdorferi sensu stricto, the agent of Lyme disease, was not detected in any tick samples. Neither Borrelia nor Rickettsia spp. were detected in any of the mammal ear biopsies (n=64) or blood samples (n=100) tested via PCR. This study documents a high prevalence in ticks of Rickettsia spp. thought to be endosymbionts, a low prevalence of relapsing fever group Borrelia in ticks, and a lack of detection of Lyme disease-group Borrelia in both ticks and mammals in an east Texas forested recreation area. Additionally, we observed low questing tick density in areas with a history of controlled burns. These results expand knowledge of tick-borne disease ecology in east Texas which can aid in directing future investigative, modeling, and management efforts.     

The Saharan antelope addax (Addax nasomaculatus) as a host for Hyalomma marginatum,tick vector of Crimean-Congo hemorrhagic fever virus

Tick infestation and pathogen prevalence in ticks infesting the Saharan antelope addax (Addax nasomaculatus) are factors that may constitute a risk for both human and animal health. In this study we describe season distribution of adult Hyalomma marginatum and analyzed the tick-borne pathogens and their seroprevalence in natural-living addax in Morocco. The results showed that addax is an important host species for H. marginatum adults. The seroprevalence of Bluetongue virus (BTV; 61.5–92.3%, n = 8/13-84/91), Coxiella burnetii (36.3–69.2%, n = 33/91-9/13) and Brucella spp. (0.0–4.8%, n = 0/50-2/42) was characterized in addax during various years (sampled animals per year, n = 13–91). Presence of Aigai virus (AIGV), a recent taxonomic differentiation of Crimean-Congo hemorrhagic fever virus (CCHFV) of 100% (4/4, years 2016 and 2017) together with Babesia ovis (75%, 3/4, year 2014), Anaplasma spp. (75%, 3/4, year 2014), Rickettsia spp. (50%, 2/4, year 2014) and Theileria spp. (25%, 1/4, year 2014) was observed in H. marginatum collected from the addax (4 pools of 10 adult ticks each). The results support the role of addax host in H. marginatum life cycle and exposure to AIGV and other tick-borne pathogens. The development of control interventions including anti-tick vaccines for wildlife species will contribute to the implementation of effective measures for the prevention and control of tick-borne diseases and might be relevant for the preservation of this threatened species and others such as Arabian oryx (Oryx leucoryx) and African elk (Taurotragus oryx) that share habitat.     

Differences in prevalence of Borrelia burgdorferi and Anaplasma spp. infection among host-seeking Dermacentor occidentalis,Ixodes pacificus,and Ornithodoros coriaceus ticks in northwestern California

Previous studies revealed that the Pacific Coast tick (Dermacentor occidentalis) is infected occasionally with the agents of Lyme disease (Borrelia burgdorferi) or human granulocytic anaplasmosis (Anaplasma phagocytophilum) and that it is an inefficient experimental vector of B. burgdorferi. The relationship of the pajahuello tick (Ornithodoros coriaceus) to each of these bacterial zoonotic agents has not been reported. The primary bridging vector of both bacterial zoonotic agents to humans is the western black-legged tick (Ixodes pacificus). Because of the spatial and temporal overlap of D. occidentalis and O. coriaceus populations with those of I. pacificus in natural foci of B. burgdorferi and A. phagocytophilum in northwestern California, we conducted field and laboratory studies to determine if the Pacific Coast tick or the pajahuello tick potentially may serve as secondary vectors of either bacterium. Our findings reconfirmed that wild-caught D. occidentalis ticks are infected infrequently with B. burgdorferi or A. phagocytophilum, but some adult ticks from dense woodlands or chaparral were found to contain two important veterinary pathogens for the first time (Anaplasma bovis, A. ovis). The high prevalence of A. bovis infection (4.3%, n = 185 ticks) within chaparral-derived ticks suggests that D. occidentalis could be an efficient vector of this rickettsia. Experimental attempts to transmit borreliae or Anaplasma spp. that may have been present in >100 wild-caught D. occidentalis adults to naïve rabbits were unsuccessful. Anaplasma spp. were not detected in O. coriaceus, but one (4.3%) of 23 nymphs was infected with B. bissettii. This finding and an antecedent report of a B. burgdorferi-like spirochete from the same tick species demonstrate that O. coriaceus sometimes acquires and transstadially passes Lyme disease group spirochetes. I. pacificus nymphs inhabiting a woodland nidus of B. burgdorferi and A. phagocytophilum had a 5-fold higher prevalence of borreliae than adult ticks from the same generational cohort. In contrast to the results of preceding studies carried out at the same site, none of the nymphal or adult ticks was PCR-positive for A. phagocytophilum. This suggests that the distribution of this rickettsia is highly focal or variable from year-to-year within this particular woodland.     

A novel Babesia sp. of the “Western Babesia group”, detected in opossums from Guatemala

Babesia spp. are tick-borne protozoans that involve birds and mammals in their transmission cycles and cause babesiosis, a severe hemolytic malaria-like disease. Opossums of the genus Didelphis are recognized hosts of tick-borne pathogens. Therefore, exploring tick-borne agents in Didelphis species is important to understand the circulation of pathogens in areas where opossums occur. In this study, we targeted Anaplasmataceae, Babesia, Borrelia and Hepatozoon DNA in ticks, blood and organ samples collected from three hunted Didelphis marsupialis specimens in eastern Guatemala. While the samples were negative for Hepatozoon and bacterial DNA, sequences of Babesia 18S rDNA, cox1 and cytb genes were retrieved from two opossums. Ticks collected on the animals included Amblyomma parvum and an undetermined Ornithodoros sp. The Babesia sp. detected in this study (Babesia sp. THB1–2) clusters phylogenetically within the “Western Babesia group”, which includes pathogenic species such as Babesia conradae, Babesia duncani, and Babesia negevi. Our results represent the first record of a Babesia sp. in Guatemala and highlight the importance of D. marsupialis as potential spreaders of ticks and pathogens in Central America.     

Molecular detection and phylogeny of Anaplasma spp. closely related to Anaplasma phagocytophilum in small ruminants from China

The genus Anaplasma comprises eight bacterial species that are obligate intracellular pathogens that affect human and animal health. The zoonotic species A. phagocytophilum is the causative agent of tick-borne fever in ruminants, and of granulocytic anaplasmosis in horses, dogs, and humans. Recently, novel strains related to A. phagocytophilum (A. phagocytophilum-like 1/Japanese variant and A. phagocytophilum-like 2/Chinese variant) have been identified. The aim of this study was to reveal the prevalence and phylogeny of A. phagocytophilum and related stains in small ruminants and ticks in China based on sequences of the 16S rRNA combined restriction fragment length polymorphism (RFLP) and groEL genes. PCR–RFLP and phylogenetic analyses based on the 16S rRNA gene showed the presence of A. phagocytophilum-like 1 and 2 variants in sampled animals from China, with prevalence rates of 22.6% (303/1338) and 0.7% (10/1338), respectively. Only A. phagocytophilum-like 1 DNA was found in Haemaphysalis longicornis. The phylogeny based on the groEL gene showed inclusion of A. phagocytophilum-like 1 and some A. phagocytophilum-like 2 strains in two unique clades distinct from, but related to, Japanese and Chinese strains of related A. phagocytophilum, respectively. One noteworthy result was that the SSAP2f/SSAP2r primers detected Ehrlichia spp. strains. Moreover, the A. phagocytophilum-like 1 and 2 strains should be considered in the differential diagnosis of caprine and ovine anaplasmosis. Further investigations should be conducted to provide additional epidemiological information about A. phagocytophilum and A. phagocytophilum-like variants in animals and ticks.     

Voles,shrews and red squirrels as sources of tick blood meals and tick-borne pathogens on an island in southwestern Finland

Molecular identification of the previous blood meal source of a questing tick (Acari: Ixodidae) from blood meal fragments was proposed a few decades ago. Following this, several blood meal assays have been developed and published, but none of them have been taken into widespread use. Recently, novel retrotransposon-based qPCR assays designed for detecting blood meal fragments of North American host species were published. We wanted to assess their function with host species present in Finland.Questing ticks were collected by cloth dragging in August-September 2021 from an island in southwestern Finland. DNA was extracted from Ixodes ricinus nymphs (n=438) and qPCR assays applied to identify larval blood meal sources (voles, shrews and red squirrels) and screen for several tick-borne human pathogens and other microbes with pathogenic potential [Borrelia spp. (including specific assays for Borrelia afzelii, Borrelia garinii, Borrelia valaisiana), Anaplasma phagocytophilum, Babesia spp., Rickettsia spp., and Neoehrlichia mikurensis].The probability of a nymph having fed as larva on either a vole, shrew or red squirrel was 0.34 (0.30 – 0.38; 95% confidence interval). Bacteria of the genus Borrelia were the most common pathogens detected, with host-specific probabilities of carrying Borrelia of 0.30 (0.18 – 0.44) for nymphs that had fed on voles, 0.23 (0.14 – 0.35) for nymphs that had fed on shrews, and 0.42 (0.28 – 0.58) for nymphs that had fed on red squirrels. Other microbes were rarely acquired from these hosts, apart from N. mikurensis from voles.This study highlights that shrews and red squirrels may equal voles as blood meal sources for I. ricinus larvae. Overall, variation in proportions of blood meals provided by these animals may be high across even proximate study areas. All studied host species appeared to be important sources for particularly Borrelia afzelii, and voles also for N. mikurensis.     

Potential for Tick-borne Bartonelloses

As worldwide vectors of human infectious diseases, ticks are considered to be second only to mosquitoes. Each tick species has preferred environmental conditions and biotopes that determine its geographic distribution, the pathogens it vectors, and the areas that pose risk for tick-borne diseases. Researchers have identified an increasing number of bacterial pathogens that are transmitted by ticks, including Anaplasma, Borrelia, Ehrlichia, and Rickettsia spp. Recent reports involving humans and canines suggest that ticks should be considered as potential vectors of Bartonella spp. To strengthen this suggestion, numerous molecular surveys to detect Bartonella DNA in ticks have been conducted. However, there is little evidence that Bartonella spp. can replicate within ticks and no definitive evidence of transmission by a tick to a vertebrate host.     

Prevalence of Rickettsia spp., Anaplasma phagocytophilum,and Coxiella burnetii in adult Ixodes ricinus ticks from 29 study areas in central and southern Sweden

A total of 887 adult Ixodes ricinus ticks (469 females and 418 males) from 29 different localities in Sweden were screened for Rickettsia, Anaplasma, and Coxiella DNA using PCR and then subjected to gene sequencing. Rickettsial DNA was detected in 9.5–9.6% of the ticks. Most of the positive ticks were infected with Rickettsia helvetica. One tick harbored another spotted fever rickettsia, closely related to or identical with R. sibirica not previously found in I. ricinus nor in Sweden. Six of the ticks (0.7%) were infected with an Anaplasma sp., presumably A. phagocytophilum. Coxiella burnetii DNA was not detected in any of the ticks. The detection of R. helvetica and A. phagocytophilum in several of the localities sampled suggests that these potentially human-pathogenic agents are common in Sweden.     

Ixodes persulcatus,a major vector of Alphaproteobacteria in Russia

Ixodes persulcatus Schulze, 1930 (I. persulcatus) is distributed from the western to the eastern borders of Russia where it is found in the taiga and in mixed forests of the European type. This tick is a known vector of viral (tick-borne encephalitis virus), spirochetal (Borrelia spp.), and protozoan (Babesia spp.) agents. In this work, we analyzed the phylogenetic position of I. persulcatus within the Prostriata based on its 18S rRNA gene. Furthermore, we review the relationship of this tick with 9 Alphaproteobacteria from the genera Rickettsia, Ehrlichia, and Anaplasma which are found in I. persulcatus in the territory of Russia. These observations suggest that I. persulcatus may be one of the more important vectors and reservoirs of Alphaproteobacteria and other microorganisms in Russia.