Human-pathogenic Anaplasma spp., and Rickettsia spp. in animals in Xi'an, China

Multi-locus sequence analysis of Anaplasma bovis in goats and ticks from Thailand, with the initial identification of an uncultured Anaplasma species closely related to Anaplasma phagocytophilum-like 1

Ticks and tick-borne pathogens (TTBP) pose a serious threat to animal and human health globally. Anaplasma bovis, an obligatory intracellular bacterium, is one of the more recent species of the Family Anaplasmaceae to be formally described. Owing to its diminutive size, microscopic detection presents a formidable challenge, leading to it being overlooked in laboratory settings lacking advanced equipment or resources, as observed in various regions, including Thailand. This study aimed to undertake a genetic analysis of A. bovis and determine its prevalence in goats and ticks utilizing three genetic markers (16S rRNA, gltA, groEL). A total of 601 goat blood and 118 tick samples were collected from 12 sampling sites throughout Thailand. Two tick species, Haemaphysalis bispinosa (n = 109), and Rhipicephalus microplus (n = 9) were identified. The results herein showed that 13.8 % (83/601) of goats at several farms and 5 % (1/20) of ticks were infected with A. bovis. Among infected ticks, A. bovis and an uncultured Anaplasma sp. which are closely related to A. phagocytophilum-like 1, were detected in each of H. bispinosa ticks. The remaining R. microplus ticks tested positive for the Anaplasma genus. A nucleotide sequence type network showed that A. bovis originated from Nan and Narathiwat were positioned within the same cluster and closely related to China isolates. This observation suggests the potential dispersal of A. bovis over considerable distances, likely facilitated by activities such as live animal trade or the transportation of infected ticks via migratory birds. The authors believe that the findings from this study will provide valuable information about TTBP in animals.

Anaplasma capra: a new emerging tick-borne zoonotic pathogen

The genus Anaplasma includes A. marginale, A. centrale, A. bovis, A. ovis, A. platys, and A. phagocytophilum transmitted by ticks, some of which are zoonotic and cause anaplasmosis in humans and animals. In 2012, a new species was discovered in goats in China. In 2015, the same agent was detected in humans in China, and it was provisionally named Anaplasma capra, referring to 2012. The studies conducted to date have revealed the existence of A. capra in humans, domestic animals, wild animals, and ticks from three different continents (Asia, Europe, and Africa). Phylogenetic analyses based on gltA and groEL sequences show that A. capra clearly includes two different genotypes (A. capra genotype-1 and A. capra genotype-2). Although A. capra human isolates are in the genotype-2 group, goat, sheep, and cattle isolates are in both groups, making it difficult to establish a host genotype-relationship. According to current data, it can be thought that human isolates are genotype-2 and while only genotype-1 is found in Europe, both genotypes are found in Asia. Anaplasma capra causes clinical disease in humans, but the situation is not yet sufficient to understand the zoonotic importance and pathogenicity in animals. In the present review, the history, hosts (vertebrates and ticks), molecular prevalence, pathogenic properties, and genetic diversity of A. capra were evaluated from a broad perspective.

Molecular investigation of Anaplasma phagocytophilum and related strains among sheep flocks from different parts of Türkiye; with a note of phylogenetic analyses of Anaplasma phagocytophilum- like 1

Anaplasma phagocytophilum is a vector-borne zoonotic pathogen and can infect various vertebrate hosts, especially cattle, sheep, goats, horses, and dogs. Molecular-based studies have revealed that the agent has a high genetic diversity and closely related strains circulate in hosts. In this study, 618 sheep blood samples obtained from different geographic regions of Türkiye were researched for A.phagocytophilum and related strains with PCR, RFLP, and DNA sequence analyses. The DNA of these pathogens was detected in 110 (17.79%) samples. RFLP assay showed that all positive samples were infected with A.phagocytophilum-like 1, whereas A.phagocytophilum-like 2 and A.phagocytophilum were not detected. Partial parts of 16 S rRNA gene of seven randomly selected positive samples were sequenced. The phylogenetic analyses of these isolates revealed that at least two A.phagocytophilum-like 1 isolates circulate among hosts in Türkiye and around the world. A.phagocytophilum-related strains have been reported in molecular-based studies over the last few years, but there is a lack of data on the vector competence, epidemiology, clinical symptoms, and genetic diversity of these pathogens. Therefore, large-scale molecular studies are still needed to obtain detailed data on the above-mentioned topics.

Anaplasma, Bartonella, and Rickettsia infections in Daurian ground squirrels (Spermophilus dauricus), Hebei, China

Rodents have been confirmed as hosts of various vector-borne zoonotic pathogens and are important for the maintenance of these microbes in nature. However, surveillance for zoonotic pathogens is limited for many wild rodent species in China, so our knowledge of pathogen ecology, genetic diversity, and the risk of cross-species transmission to humans is limited. In this study, 165 spleen samples of Daurian ground squirrels (Spermophilus dauricus) were collected from Weichang Manchu and the Mongolian Autonomous County of Hebei Province, China, and Rickettsia, Bartonella, and Anaplasma were identified by DNA detection using polymerase chain reaction (PCR). Sequence analysis identified eight bacterial pathogens: R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, B. grahamii, B. jaculi, A. capra, and Candidatus Anaplasma cinensis. Co-infection of B. grahamii and R. raoultii in one sample was observed. Our results demonstrated the genetic diversity of bacteria in Daurian ground squirrels and contributed to the distribution of these pathogens. Six species, A. capra, R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, and B. grahamii, are known to be pathogenic to humans, indicating a potential public health risk to the local human population, especially to herders who frequently have close contact with Daurian ground squirrels and are thus exposed to their ectoparasites.

Molecular detection of Rickettsiales and a potential novel Ehrlichia species closely related to Ehrlichia chaffeensis in ticks (Acari: Ixodidae) from Shaanxi Province, China, in 2022 to 2023

Important tick-borne diseases include spotted fever group Rickettsia (SFGR), Anaplasma, and Ehrlichia, which cause harm to animal and human health. Ixodidae are the primary vectors of these pathogens. We aimed to analyze the prevalence and genetic diversity of SFGR, Anaplasma, and Ehrlichia species in the Ixodidae in Shaanxi Province, China. Herein, 1,113 adult Ixodidae ticks were collected from domestic cattle and goats, and detected using nested PCR. A total of four Ixodidae species were collected and Ca. R. jingxinensis (20.58%, 229/1113), A. bovis (3.05%, 34/1113), A. capra (3.32%, 37/1113), A. marginale (0.18%, 2/1113), E. sp. Yonaguni138 (0.18%, 2/1113), and a potent novel Ehrlichia species named E. sp. Baoji96 (0.09%, 1/1113) were detected. A. marginale was detected for the first time in Rhipicephalus microplus. E. sp. Baoji96 was closely related to E. chaffeensis and was first identified in Haemaphysalis longicornis. In addition, co-infection with two Rickettsiales pathogens within an individual tick was detected in 10 (1.54%) ticks. This study provides a reference for the formulation of biological control strategies for ticks and tick-borne diseases in Shaanxi Province, and could lead to an improved control effect.

Microbial diversity of ticks and a novel typhus group Rickettsia species (Rickettsiales bacterium Ac37b) in Inner Mongolia, China

Ticks can carry multiple pathogens, and Inner Mongolia's animal husbandry provides excellent environmental conditions for ticks. This study characterized the microbiome of ticks from different geographical locations in Inner Mongolia; 905 Dermacentor nuttalli and 36 Ixodes persulcatus were collected from sheep in three main pasture areas and from bushes within the forested area. Mixed DNA samples were prepared from three specimens from each region and tick species. Microbial diversity was analyzed by 16S rRNA sequencing, and α and β diversity were determined. The predominant bacterial genera were Rickettsia (54.60%), including Rickettsiales bacterium Ac37b (19.33%) and other Rickettsia (35.27%), Arsenophonus (11.21%), Candidatus Lariskella (10.84%), and Acinetobacter (7.17%). Rickettsia bellii was identified in I. persulcatus, while Rickettsiales bacterium Ac37b was found in D. nuttalli from Ordos and Chifeng. Potential Rickettsia and Anaplasma coinfections were observed in the Ordos region. Tick microbial diversity analysis in Inner Mongolia suggests that sheep at the sampling sites were exposed to multiple pathogens.

Molecular survey of Anaplasma phagocytophilum and related variants in water buffaloes: The first detection of Anaplasma phagocytophilum-like 1

Anaplasma phagocytophilum infects various hosts and lead to mild to severe infection. Currently, two A.phagocytophilum-related variants have been documented in different countries. Although limited, there are studies revealing the presence of A.phagocytophilum in water buffaloes, but no study investigating A.phagocytophilum-like 1 and -like 2. A.phagocytophilum and related variants were investigated using PCR, PCR-RFLP, and DNA sequence analysis in water buffaloes in Türkiye. 364 buffalo blood samples were examined for A.phagocytophilum and related strains. Seven buffaloes were determined to be positive with PCR and PCR-RFLP revealed that all samples were A.phagocytophilum-like 1. According to the partial sequence of 16 S rRNA gene, A.phagocytophilum like-1 may split into two different variants. This work supplies the first molecular report of A.phagocytophilum-like 1 in water buffaloes. However, a lack of information is present on the pathogen's clinical manifestations and vector species. There is still a need to investigate vectors and clinical signs of the pathogen.

Molecular Detection of Tick-Borne Bacterial and Protozoan Pathogens in Haemaphysalis longicornis (Acari: Ixodidae) Ticks from Free-Ranging Domestic Sheep in Hebei Province, China

Ticks and tick-borne pathogens significantly threaten human and animal health worldwide. Haemaphysalis longicornis is one of the dominant tick species in East Asia, including China. In the present study, 646 Ha. longicornis ticks were collected from free-ranging domestic sheep in the southern region of Hebei Province, China. Tick-borne pathogens of zoonotic and veterinary importance (i.e., Rickettsia, Anaplasma, Ehrlichia, Borrelia, Theileria, and Hepatozoon spp.) were detected in the ticks using PCR assays and sequence analysis. The prevalence rates of these pathogens were 5.1% (33/646), 15.9% (103/646), 1.2% (8/646), 17.0% (110/646), 0.15% (1/646), and 0.15% (1/646), respectively. For Rickettsia spp., R. japonica (n = 13), R. raoultii (n = 6), and Candidatus R. jingxinensis (n = 14) were detected for the first time in the province, while several Anaplasma spp. were also detected in the ticks, including A. bovis (n = 52), A. ovis (n = 31), A. phagocytophilum (n = 10), and A. capra (n = 10). A putative novel Ehrlichia spp. was also found with a prevalence of 1.2% in the area. The present study provides important data for effectively controlling ticks and tick-borne diseases in the Hebei Province region of China.

The life cycle of Dermacentor nuttalli from the Qinghai-Tibetan Plateau under laboratory conditions and detection of spotted fever group Rickettsia spp

Dermacentor nuttalli has been a focus of study because tick-borne pathogens have been widely identified in this tick from northern and southwestern China. The aim of this study was to characterize the life cycle of D. nuttalli under laboratory conditions and to detect spotted fever group (SFG) Rickettsia in the midgut and salivary glands of both field-collected and first laboratory generation adults. D. nuttalli ticks were collected in the field on the Qinghai-Tibetan Plateau from March to April 2021 and their life cycle was studied under laboratory conditions. Tick identify was molecularly confirmed, and SFG Rickettsia were detected in the midgut and salivary glands of males and females by PCR targeting different rickettsial genes. The results showed that the life cycle of D. nuttalli under laboratory conditions was completed in an average of 86.1 days. High positivity of Rickettsia spp. was detected in the midgut and salivary glands of both males (92.0%) and females (93.0%) of field-collected D. nuttalli ticks. However, a relatively lower positivity (4.0-6.0%) was detected in first laboratory generation adults. Furthermore, sequencing analysis showed that the Rickettsia sequences obtained in this study shared 98.6 to 100% nucleotide identity with Rickettsia slovaca and Rickettsia raoultii isolated from Dermacentor spp. in China. Phylogenetic analysis of Rickettsia spp. based on the gltA, ompA, ompB and sca4 genes revealed that the Rickettsia sequences obtained could be classified as belonging to R. slovaca and R. raoultii clades. This study described for the first time the life cycle of D. nuttalli from the Qinghai-Tibetan Plateau under laboratory conditions. Two species of SFG Rickettsia were detected in the midgut and salivary glands of males and females in both field-collected and first laboratory-generation adults of D. nuttalli. Our study provides new insights into pathogen detection in ticks in the Qinghai-Tibet Plateau, and the relationships among hosts, ticks, and pathogens.

Diversity of Rickettsiales bacteria in five species of ticks collected from Jinzhai County, Anhui Province, China in 2021-2022

The order Rickettsiales in the class Alphaproteobacteria comprises vector-borne pathogens of both medical and veterinary importance. Ticks, as a group, are second only to mosquitoes as vectors of pathogens to humans, playing a critical role in the transmission of rickettsiosis. In the present study, 880 ticks collected from Jinzhai County, Lu'an City, Anhui Province, China in 2021-2022 were identified as belonging to five species from three genera. DNA extracted from individual ticks was examined using nested polymerase chain reaction targeting the 16S rRNA gene (rrs), and the gene fragments amplified were sequenced to detect and identify Rickettsiales bacteria in the ticks. For further identification, the rrs-positive tick samples were further amplified by PCR targeting the gltA and groEL gene and sequenced. As a result, 13 Rickettsiales species belonging to the genera Rickettsia, Anaplasma, and Ehrlichia were detected, including three tentative species of Ehrlichia. Our results reveal the extensive diversity of Rickettsiales bacteria in ticks from Jinzhai County, Anhui Province. There, emerging rickettsial species may be pathogenic and cause under-recognized diseases. Detection of several pathogens in ticks that are closely related to human diseases may indicate a potential risk of infection in humans. Therefore, additional studies to assess the potential public health risks of the Rickettsiales pathogens identified in the present study are warranted.

The detection and phylogenetic analysis of Anaplasma phagocytophilum-like 1, A. ovis and A. capra in sheep: A. capra divides into two genogroups

In this study, the presence, prevalence, and genotypes of Anaplasma phagocytophilum, A. ovis, and A. capra in sheep were investigated based on 16 S SSU rRNA, groEL, and gtlA gene-specific polymerase chain reaction (PCR), respectively. The sequences of the genes were used for detection of the phylogenetic position of the species. Additionally, a restriction fragment length polymorphism (RFLP) were carried out for discrimination of A. phagocytophilum and related variants (A. phagocytophilum-like 1 and 2). The prevalence of Anaplasma spp. was found as 25.8% (101/391), while it was found that A. ovis, A. phagocytophilum-like 1, and A. capra are circulating in the sheep herds in Kyrgyzstan, according to the PCRs, RFLP and the partial DNA sequencing results. The positivity rates of A. phagocytophilum-like 1, A. ovis, and A. capra genotype-1 were 6.9, 22.5, and 5.3%, respectively. A total of 32 (8.2%) sheep were found to be mix infected. Moreover, phylogenetic analyses and sequence comparison with those available in the GenBank showed that A. capra formed two distinct genetic groups (A. capra genotype-1 and A. capra genotype-2). Considering the zoonotic potential of these species, it may be necessary to make changes in the interpretation of anaplasmosis cases in animals and there is a need for further studies to determine the pathogenicity of the species/genotypes circulating in animals.

Buffaloes as new hosts for Anaplasma capra: Molecular prevalence and phylogeny based on gtlA, groEL, and 16S rRNA genes

Anaplasma capra is a tick-borne pathogen that was discovered for the first time in goats in China in 2012. The studies carried out from the first detection in China to the present have revealed the presence of this species in eight countries including Angola, France, Iranian, South Korea, Kyrgyzstan, Malaysia, Spain, and Türkiye in three continents (Africa, Asia, and Europe). It has also been determined that humans, sheep, cattle, dog, and wild animals are the hosts of A. capra. It was investigated whether water buffaloes were the host of A. capra using nested-PCR and DNA sequencing in this study. The prevalence of A. capra in Turkish water buffalo herds was investigated and phylogenetic analyzes were performed on the basis of gltA, groEL, and 16S rRNA genes. A total of 364 water buffalo blood samples were examined in terms of A. capra using gltA gene species-specific nested-PCR. A. capra were detected in 52 of 364 (14.28%) blood samples. There was no statistically significant difference between the prevalence, gender, and age parameters. The gltA, groEL, and 16S rRNA genes in randomly selected three positive samples were sequenced. A. capra isolates obtained from water buffaloes in this study shared 85.20-100%(gltA), 89.84-100%(groEL), and 99.82-100%(16S rRNA) nucleotide similarity with A.capra isolates present in GeneBank. Phylogenetic analyses of gtlA and groEL genes revealed that A. capra divided in two different genogroups. In conclusion, this study revealed that water buffalo is a new host of A. capra. However, comprehensive studies are needed to determine the pathogenicity, vectors, and biological properties of A. capra in this new host.

Molecular Characterization of Anaplasma spp. among Dairy, Cashmere, and Meat Goats in Shaanxi Province, Northwestern China

Anaplasma spp. are important tick-borne pathogens endangering the health of humans and various animals. Although several studies have reported Anaplasma infection in livestock in China, little is known about the impact of production categories on the occurrence of Anaplasma species. In the present study, PCR tools targeting the 16S rRNA and msp4 genes were applied to investigate the prevalence of Anaplasma spp. in 509 blood samples of dairy (n = 249), cashmere (n = 139), and meat (n = 121) goats from Shaanxi province. The prevalence of Anaplasma spp. was 58.5% (298/509) in goats, and significant differences (p < 0.001) were identified in the prevalence among production categories, with the highest in meat goats (84.3%, 102/121), followed by cashmere goats (58.3%, 81/139) and dairy goats (46.2%, 115/249). Significant differences (p < 0.001) in prevalence were also found among sampling sites and age groups. Meanwhile, the prevalence was 36.9% (188/509) for A. phagocytophilum, 36.1% (184/509) for A. bovis, and 11.0% (56/509) for A. ovis, and significant differences (p < 0.001) in prevalence of A. phagocytophilum, A. bovis and A. ovis were recognized among production categories and sampling sites. A. phagocytophilum, A. bovis and A. ovis were dominant species in meat, dairy, and cashmere goats, respectively, and A. ovis was absent in meat goats. Co-infections were found in 124 (24.4%) investigated samples. Goats aged < 2, 3−6, and 7−12 months, and goats from Qingjian and Zhenba were risk factors associated with the occurrence of Anaplasma. Phylogenetic analysis indicated separate clades for the distribution of A. phagocytophilum from different ruminant, reflecting potential host adaption within this species. This study reported the colonization occurrence of Anaplasma spp. among production categories in goats in Shaanxi province and enriched our knowledge on the transmission of Anaplasma spp. in goats in China. Considering the existence of zoonotic A. phagocytophilum in goats in this study and previous reports, interventions based on One Health are needed to be developed to control the transmission of Anaplasma spp. between humans and animals.

Illuminating the bacterial microbiome of Australian ticks with 16S and Rickettsia-specific next-generation sequencing

Next-generation sequencing (NGS) studies show that mosquito and tick microbiomes influence the transmission of pathogens, opening new avenues for vector-borne pathogen control. Recent microbiological studies of Australian ticks highlight fundamental knowledge gaps of tick-borne agents. This investigation explored the composition, diversity and prevalence of bacteria in Australian ticks (n = 655) from companion animals (dogs, cats and horses). Bacterial 16S NGS was used to identify most bacterial taxa and a Rickettsia-specific NGS assay was developed to identify Rickettsia species that were indistinguishable at the V1-2 regions of 16S. Sanger sequencing of near full-length 16S was used to confirm whether species detected by 16S NGS were novel. The haemotropic bacterial pathogens Anaplasma platys, Bartonella clarridgeiae, “Candidatus Mycoplasma haematoparvum” and Coxiella burnetii were identified in Rhipicephalus sanguineus (s.l.) from Queensland (QLD), Western Australia, the Northern Territory (NT), and South Australia, Ixodes holocyclus from QLD, Rh. sanguineus (s.l.) from the NT, and I. holocyclus from QLD, respectively. Analysis of the control data showed that cross-talk compromises the detection of rare species as filtering thresholds for less abundant sequences had to be applied to mitigate false positives. A comparison of the taxonomic assignments made with 16S sequence databases revealed inconsistencies. The Rickettsia-specific citrate synthase gene NGS assay enabled the identification of Rickettsia co-infections with potentially novel species and genotypes most similar (97.9–99.1%) to Rickettsia raoultii and Rickettsia gravesii. “Candidatus Rickettsia jingxinensis” was identified for the first time in Australia. Phylogenetic analysis of near full-length 16S sequences confirmed a novel Coxiellaceae genus and species, two novel Francisella species, and two novel Francisella genotypes. Cross-talk raises concerns for the MiSeq platform as a diagnostic tool for clinical samples. This study provides recommendations for adjustments to Illuminaʼs 16S metagenomic sequencing protocol that help track and reduce cross-talk from cross-contamination during library preparation. The inconsistencies in taxonomic assignment emphasise the need for curated and quality-checked sequence databases.

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Bacterial pathogens identified in ticks from companion animals with 16S NGS.

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Sanger sequencing confirmed novel Coxiellaceae gen. sp. and Francisella.

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“Candidatus Rickettsia jingxinensis” was identified with Rickettsia-specific NGS.

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Comparison of taxonomic assignments in 16S sequence databases revealed errors.

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Modifications to the 16S metagenomic library protocol (Illumina) are provided.

The Use and Limitations of the 16S rRNA Sequence for Species Classification of Anaplasma Samples

With the advent of cheaper, high-throughput sequencing technologies, the ability to survey biodiversity in previously unexplored niches and geographies has expanded massively. Within Anaplasma, a genus containing several intra-hematopoietic pathogens of medical and economic importance, at least 25 new species have been proposed since the last formal taxonomic organization. Given the obligate intracellular nature of these bacteria, none of these proposed species have been able to attain formal standing in the nomenclature per the International Code of Nomenclature of Prokaryotes rules. Many novel species’ proposals use sequence data obtained from targeted or metagenomic PCR studies of only a few genes, most commonly the 16S rRNA gene. We examined the utility of the 16S rRNA gene sequence for discriminating Anaplasma samples to the species level. We find that while the genetic diversity of the genus Anaplasma appears greater than appreciated in the last organization of the genus, caution must be used when attempting to resolve to a species descriptor from the 16S rRNA gene alone. Specifically, genomically distinct species have similar 16S rRNA gene sequences, especially when only partial amplicons of the 16S rRNA are used. Furthermore, we provide key bases that allow classification of the formally named species of Anaplasma.

The first molecular detection of Anaplasma capra in domestic ruminants in the central part of Turkey, with genetic diversity and genotyping of Anaplasma capra

Tick-borne diseases have been an increasing threat to human and animal health all over the world. Anaplasmosis is one of the emerging tick-borne diseases and has zoonotic potential. A new novel species, which was detected in China in 2010-2012 and provisionally named Anaplasma capra in 2015, causes zoonotic infections and infects many different animal species. In this study, we investigated the presence of A. capra in domestic ruminants from Turkey. A total of 468 blood samples (cattle, sheep, and goat) were examined by the gltA gene-specific nested polymerase chain reaction, revealing the presence of A. capra in six samples (1.28%): one of them from cattle (0.41%) and the other five from sheep (3.22%). According to DNA sequences results of the gltA gene, A. capra isolates identified in the present study were shown high nucleotide similarity with A. capra isolates detected from different hosts. However, the nucleotide differences were detected in the same nucleotide positions between A. capra isolates. For this reason, we thought that at least two different A. capra genotypes could be circulating in the world. As a result, it is seen that A. capra, which was determined to be a new species with zoonotic potential, was revealed in European and Asian countries and in different hosts. In order to raise awareness about human anaplasmosis infections, it is important to reveal the prevalence of the species in the world. The emergence of A. capra in Turkey reveals the need for a re-evaluation of the human and animal health risk analysis in terms of anaplasmosis.

Recent Progress on Tick-Borne Animal Diseases of Veterinary and Public Health Significance in China

Ticks and tick-borne diseases pose a growing threat to human and animal health, which has brought great losses to livestock production. With the continuous expansion of human activities and the development of natural resources, there are more and more opportunities for humans to contract ticks and tick-borne pathogens. Therefore, research on ticks and tick-borne diseases is of great significance. This paper reviews recent progress on tick-borne bacterial diseases, viral diseases, and parasitic diseases in China, which provides a theoretical foundation for the research of tick-borne diseases.

The Common Occurrence of Theileria ovis in Tibetan Sheep and the First Report of Theileria sinensis in Yaks from Southern Qinghai, China

PURPOSE

The tick-borne protozoa piroplasms, including Theileria and Babesia, are the cause of substantial economic losses to the livestock industry. However, in southern Qinghai province, China, there are limited information on the molecular characteristics of piroplasms. This study therefore aimed at determining the prevalence and genetic diversity of piroplasms.

METHODS

In order to detect piroplasms, we examined 330 yaks and 236 Tibetan sheep blood samples by nested PCR. The differences in piroplasms prevalence in relation to different risk factors was analyzed using SPSS 26. Phylogenetic analysis based on 18S rRNA sequences was inferred using MEGA 7.

RESULTS

During this study, Theileria spp. were detected in 33.6% (111/330) of yaks and 94.1% (222/236) of Tibetan sheep, but no Babesia was identified. Importantly, a comparison study revealed that T. ovis infection was highly prevalent in sheep (94.1%) but infrequent in yaks (6.1%), while T. sinensis was host-specific to yaks with an infection rate of 27.6%. In addition, male animals were more likely to be infected by T. sinensis and female animals were more likely to be infected by T. ovis. And animals below 4000 m areas reported a higher infection rate with T. sinensis (26.1% vs. 2.9%, p < 0.001). Alongside these differences in prevalence, we found a significantly higher T. sinensis infection rate in separated-grazing livestock (22.2% vs. 3.7%, p < 0.001), while mixed-grazing ruminants had a higher T. ovis infection rate (50.0% vs. 39.0%, p = 0.014). Furthermore, sequence analysis revealed that the 18S rRNA sequences obtained in this study shared 86.9-100.0% identities with each other and they were clustered into T. sinensis or T. ovis.

CONCLUSION

To our knowledge, this is the first report of T. sinensis in Qinghai region. In addition, high prevalence of the generally sub-clinical T. ovis in sheep indicates extensive exposure to ticks and transmission of tick-borne pathogens with a significant economic impact. This study provides insights into the distribution and genetic diversity of Theileria in China.

First molecular detection of Anaplasma species in cattle from Kyrgyzstan; molecular identification of human pathogenic novel genotype Anaplasma capra and Anaplasma phagocytophilum related strain

Anaplasmosis is a rickettsial infection with significant effects on human and animal health, and the discovery of new species or genotypes with zoonotic potential in recent years has increased this importance. The aim of this study was to provide the first assessment of the molecular etiology and prevalence of bovine anaplasmosis in Kyrgyzstan (specifically in the Chuy, Talas, Djalal-Abad, Naryn, and Issyk-Kul regions). The prevalence of bovine anaplasmosis was determined as 1.7% (6/358). PCR and partial DNA sequencing results of the 16S ribosomal RNA (rRNA) gene revealed that Anaplasma centrale, A. phagocytophilum like-1, and the human pathogenic novel genotype A. capra are circulating in cattle herds in Kyrgyzstan. Six DNA nucleotide sequences obtained in this study were deposited in GenBank under the following accession numbers: A. centrale (MW672117, MW672118, MW672119, MW672120), A. phagocytophilum (MW672121), and A. capra (MW672115).

Diversity of Anaplasma species and importance of mixed infections in roe deer from Spain

Although wildlife can act as reservoirs of some Anaplasma species, studies on the presence and distribution of Anaplasma spp. in wild cervids are mainly limited and focused on zoonotic species. In order to identify the Anaplasma species in roe deer from Spain and to detect co-infections, 224 spleen samples were tested for Anaplasma spp. using a commercial qPCR; positive samples were further characterized using generic 16S rRNA primers and species-specific primers targeting the msp2 and groEL genes. Anaplasma DNA was detected in the 50.9% of samples, and four Anaplasma species were identified. Anaplasma phagocytophilum (43.8%) was predominant, followed by Anaplasma bovis (13.8%), Anaplasma capra (5.8%) and Anaplasma ovis (2.2%). In addition, strains similar to Anaplasma platys were found in nine animals. Most positive roe deer (71.9%) were infected with a single Anaplasma species, whereas co-infections with two (19.3%) or three (8.8%) Anaplasma species were also found. This study confirms the widespread occurrence of Anaplasma spp. in roe deer from Spain, being the first report of A. platys-like strains and A. capra in this cervid; it is also the first report of A. capra in Spain. The detection of Anaplasma species pathogenic for humans and/or domestic animals in roe deer suggests that this cervid may play a role in the sylvatic cycle of these bacteria contributing to the appearance of clinical anaplasmosis cases. In addition, co-infections are common in roe deer revealing that Anaplasma species specific PCR assays are essential for a reliable identification as well as for determining their real prevalence.

Hyalomma spp. ticks and associated Anaplasma spp. and Ehrlichia spp. on the Iran-Pakistan border

Background

Anaplasmosis and ehrlichiosis are tick-borne diseases affecting humans and livestock, particularly in tropical and subtropical regions. Animal husbandry is the main activity of people on the borders of Iran and Pakistan, with thousands of cattle crossing the border each week.

Methods

PCR and sequencing of the 16S rRNA gene was used to determine the percentage and geographical distribution of the pathogens carried by Hyalomma spp. (n = 306) collected from 126 goats, cattle and camels in the region between November 2017 and late March 2018.

Results

In total, 1124 hard ticks including 1020 Hyalomma spp. ticks belonging to six species (Hyalomma anatolicum, Hyalomma asiaticum, Hyalomma marginatum, Hyalomma dromedarii, Hyalomma schulzei, and Hyalomma detritum) were found on the borders of Iran and Pakistan, with H. anatolicum being the most prevalent tick species. Anaplasma spp. and/or Ehrlichia spp. DNA was found in 68.3% of the engorged tick specimens (n = 256). Sequencing of a subset (12.6%) of PCR-positive samples revealed Anaplasma ovis, Anaplasma marginale, and Ehrlichia ewingii DNA in 81.8%, 9.1%, and 9.1% of the ticks, respectively. To our knowledge, this is the first report of E. ewingii, an important human pathogen, in Iran.

Conclusions

Based on molecular analysis, three pathogenic Anaplasmataceae were detected in six Hyalomma spp. parasitizing cattle, goats and camels, confirming the presence of these pathogens along the Iran-Pakistan border.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04956-3.

Molecular investigation of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern region of the Republic of Korea

In this study, we investigated the presence of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern provinces of the Republic of Korea (ROK). We identified 33 ticks from three tick species, namely Amblyomma testudinarium (60.6%), Haemaphysalis longicornis (27.3%), and Ixodes nipponensis (12.1%) in order of occurrence via morphology and 16S rDNA-targeting polymerase chain reaction (PCR). Tick-borne pathogens were detected in 16 ticks using pathogen-specific PCR. From the results, 12 ticks (36.4%) tested positive for spotted fever group (SFG) Rickettsia: Rickettsia monacensis (1/12), R. tamurae (8/12), and Candidatus Rickettsia jingxinensis (3/12). Three ticks (9.1%) were positive for Anaplasma phagocytophilum. In addition, three ticks (9.1%) tested positive for Babesia gibsoni (1/3) and B. microti (2/3). In conclusion, we identified three tick species; the most common species was A. testudinarium, followed by H. longicornis and I. nipponensis. SFG Rickettsia, A. phagocytophilum, and Babesia spp. were the most frequently detected pathogens in ticks removed from tick-bitten humans. To our knowledge, this is the first report of R. tamurae and Ca. R. jingxinensis detection in Korea. The present results will contribute to the understanding of tick-borne infections in animals and humans in the ROK.

The Novel Zoonotic Pathogen, Anaplasma capra, Infects Human Erythrocytes, HL-60, and TF-1 Cells In Vitro

Anaplasma capra, a species of the family Anaplasmataceae, is zoonotic tick-borne obligate intracellular bacteria. There have been no reports of human infection with this pathogen since 2015. Therefore, the zoonotic characteristics of A. capra need to be further studied. To verify the ability of A. capra to infect human cells, A. capra were inoculated in human erythrocytes, HL-60, and TF-1 cell lines in vitro. Cell smears were taken after inoculation, using Giemsa staining, transmission electron microscope (TEM), chromogenic in situ hybridization and immunocytochemistry for detection. In the Giemsa staining, many dark colored corpuscles or purple granules were seen in the inoculated erythrocytes, HL-60, and TF-1 cells. The results of chromogenic in situ hybridization show that there were brown precipitates on the surface of most erythrocytes. Immunocytochemistry results show many dark brown vacuolar structures or corpuscles in the cytoplasm of erythrocytes, HL-60, and TF-1 cell lines. The A. capra morulae were seen in the cytoplasm of both HL-60 and TF-1 in TEM, and their diameter was about 295–518 nm. Both dense-cored (DC) and reticulate cell (RC) form morulae could be seen. This study confirmed the ability of A. capra to infect human erythrocytes, HL-60, and TF-1. This study is of profound significance in further verifying the zoonotic characteristics of the pathogen and for establishing an in vitro cultivation model.

Epizootic Situation on Anaplasmosis of Small Ruminants in the Irkutsk Region

Anaplasmosis of ruminants is a group of natural focal infections caused by bacteria from the genus Anaplasma of the Anaplasmataceae family. The main etiological agent of anaplasmosis in sheep, goats, and wild ruminants is Anaplasma ovis, which parasitizes in the erythrocytes of these animals. The purpose of this study was the finding and identification of Anaplasma spp. in the blood of small ruminants using genetic methods and obtaining data on the distribution of anaplasmosis in the Irkutsk region. 20 goat blood samples, 611 sheep blood samples and 209 Dermacentor nuttalli ticks from 12 districts of the Irkutsk region were examined for the presence of Anaplasma spp. Only one type of anaplasma, A. ovis, was found among the genotyped samples. A. ovis was found in the blood of sheep and goats in all of the studied districts of the Irkutsk region. The proportion of sheep blood samples containing anaplasma DNA varied from 30 % to 85 %, in goats – from 10 % to 100 % in different districts, and averaged 57.8 % in sheep and 55,0 % in goats. Frequency of infection of D. nuttalli ticks with A. ovis was 5.7 %. The nucleotide sequences of the samples detected in the blood of small ruminants on the territory of the Irkutsk region differed from each other by a single nucleotide substitution and were identical to the sequences of the type strain Haibei, as well as the sequences of A. ovis previously found in the blood of sheep from Mongolia, deer from China, and Dermacentor niveus and Dermacentor nuttalli ticks from China. These sequences were also identical to the sequences previously found in the blood of sheep from Altai and in Dermacentor nuttalli ticks from Tuva, which indicates the wide distribution of these A. ovis genovariants in Siberia and the probable role of D. nuttalli as a carrier of the agent of anaplasmosis of small ruminants in the Irkutsk region.

Screening of tick-borne pathogens in argasid ticks in Zambia: Expansion of the geographic distribution of Rickettsia lusitaniae and Rickettsia hoogstraalii and detection of putative novel Anaplasma species

Ticks (Ixodidae and Argasidae) are important arthropod vectors of various pathogens that cause human and animal infectious diseases. Many previously published studies on tick-borne pathogens focused on those transmitted by ixodid ticks. Although there are increasing reports of viral pathogens associated with argasid ticks, information on bacterial pathogens they transmit is scarce. The aim of this molecular study was to detect and characterize Rickettsia and Anaplasmataceae in three different argasid tick species, Ornithodoros faini, Ornithodoros moubata, and Argas walkerae collected in Zambia. Rickettsia hoogstraalii and Rickettsia lusitaniae were detected in 77 % (77/100) of Ar. walkerae and 10 % (5/50) of O. faini, respectively. All O. moubata pool samples (n = 124) were negative for rickettsial infections. Anaplasmataceae were detected in 63 % (63/100) of Ar. walkerae and in 82.2 % (102/124) of O. moubata pools, but not in O. faini. Phylogenetic analysis based on the concatenated sequences of 16S rRNA and groEL genes revealed that Anaplasma spp. detected in the present study were distinct from previously validated Anaplasma species, indicating that the current knowledge on the diversity and vector range of Anaplasma spp. is incomplete. Our findings highlight new geographical records of R. lusitaniae and R. hoogstraalii and confirm that the wide geographic distribution of these species includes the African continent. The data presented here increase our knowledge on argasid tick-borne bacteria and contribute toward understanding their epidemiology.

Genetic diversity of Anaplasma bacteria: Twenty years later

The genus Anaplasma (family Anaplasmataceae, order Rickettsiales) includes obligate intracellular alphaproteobacteria that multiply within membrane-bound vacuoles and are transmitted by Ixodidae ticks to vertebrate hosts. Since the last reclassification of Anaplasmataceae twenty years ago, two new Anaplasma species have been identified. To date, the genus includes eight Anaplasma species (A. phagocytophilum, A. marginale, A. centrale, A. ovis, A. bovis, A. platys, A. odocoilei, and A. capra) and a large number of unclassified genovariants that cannot be assigned to known species. Members of the genus can cause infection in humans and a wide range of domestic animals with different degrees of severity. Long-term persistence which, in some cases, is manifested as cyclic bacteremia has been demonstrated for several Anaplasma species. Zoonotic potential has been shown for A. phagocytophilum, the agent of human granulocytic anaplasmosis, and for some other Anaplasma spp. that suggests a broader medical relevance of this genus. Genetic diversity of Anaplasma spp. has been intensively studied in recent years, and it has been shown that some Anaplasma spp. can be considered as a complex of genetically distinct lineages differing by geography, vectors, and host tropism. The aim of this review was to summarize the current knowledge concerning the natural history, pathogenic properties, and genetic diversity of Anaplasma spp. and some unclassified genovariants with particular attention to their genetic characteristics. The high genetic variability of Anaplasma spp. prompted us to conduct a detailed phylogenetic analysis for different Anaplasma species and unclassified genovariants, which were included in this review. The genotyping of unclassified genovariants has led to the identification of at least four distinct clades that might be considered in future as new candidate species.

Anaplasma platys-Like Infection in Goats, Beijing, China

As one of the important tick-borne zoonotic pathogens, Anaplasma has both veterinary and public health significance. Here, we performed a survey of Anaplasma infection in the goats from a farm in Beijing, China, and found 44.6% (41/92) were infected with Anaplasma capra, and 22.8% (21/92) were infected with Anaplasma sp. This Anaplasma sp. bacterium was close to a recently emerging Anaplasma platys strain based on gltA and groEL gene phylogenetic analysis. As to further understand the characteristics of Anaplasma sp., we raised a couple of positive goats (n = 2) in the laboratory with tick-free settings. We observed inappetence, vomiting, high fever, and weakness of limbs in the goat's offspring (n = 3). In addition, the blood samples from all offspring were all positive of this Anaplasma spp. We did not see any intracellular morulae in neutrophils, monocytes, and erythrocytes, but we identified some in the platelets of the blood smears from the positive goats by light microscopy. We named it A. platys-like and suggested it may infect platelets and be transmitted vertically through the placenta of goats. These findings deserve further evaluation.

Molecular characterization of tick-borne bacteria and protozoans in yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus) in the Qinghai-Tibetan Plateau Area, China

Due to the specific plateau climate, a variety of unique animals live in the Qinghai-Tibetan Plateau Area (QTPA) including yaks (Bos grunniens), Tibetan sheep (Ovis aries) and Bactrian camels (Camelus bactrianus). However, information on tick-borne diseases (TBDs) in the QTPA and on the molecular characteristics of tick-borne pathogens (TBPs) in the area is limited. Therefore, the aim of this study was to investigate Anaplasma spp., Babesia spp., Theileria spp., Borrelia burgdorferi sensu lato and Rickettsia spp. infecting yaks, Tibetan sheep and camels in this area. A total of 276 animals were screened. Overall, 84.5% (164/194) of yaks, 58% (23/40) of Tibetan sheep, and 38% (16/42) of camels tested positive for at least one pathogen. Theileria spp., Anaplasma ovis and spotted fever group (SFG) Rickettsia spp. were detected as TBPs in the current study with overall infection rates of 10.9% (30/276), 8.3% (23/276) and 62.9% (171/276), respectively. Further study revealed that 1.5% (3/194) of the yaks were infected with Theileria sp. OT3, 1.5% (3/194) with T. luwenshuni, 6.2% (12/194) with T. uilenbergi, 1.1% (2/194) with T. ovis and 82% (159/194) with SFG Rickettsia spp. It was also shown that 58% (23/40) of the Tibetan sheep were infected with A. ovis and 15% (6/40) with T. ovis. Among the camels, 10% (4/42) were infected with T. equi, while 29% (12/42) were positive for Rickettsia spp. Sequence analysis revealed that the Rickettsia spp. infecting yaks and camels were Rickettsia raoultii and Rickettsia slovaca. To the best of our knowledge, this study reports the first detection and characterization of these pathogens in yaks, Tibetan sheep and camels in the country, except for T. luwenshuni infections in yaks.

Molecular phylogeny and genetic diversity based on msp1a, groEL and gltA genes of Anaplasma ovis Tunisian isolates compared to available worldwide isolates and strains

Anaplasma ovis, the causative agent of ovine anaplasmosis in tropical and subtropical countries, is a tick-borne obligatory intraerythrocytic bacterium of sheep, goats and wild ruminants. In Tunisia, data about the molecular phylogeny and the genetic diversity of A. ovis isolates are limited to the analysis of msp4 and groEL genes. The aim of this study was to genetic characterize 40 A. ovis isolates infecting 28 goats, 10 sheep, one camel and one Rhipicephalus turanicus tick located in different geographic regions of Tunisia on the basis of 3 partial genes (gltA, groEL and msp1a). Sequence analysis revealed 6 and 17 different genotypes in the partial gltA and groEL genes, respectively. Phylogenetic analysis revealed, as expected for the groEL gene, that sequences from small ruminants and their infesting ticks clustered separately from those isolated from camels. The analysis of amino-acid Msp1a sequences identified 18 novel genotypes of Msp1a repeats from 20 A. ovis isolates. These Msp1a repeats were highly variable with 33-47 amino-acids, and the number of repeats is one for 19 isolates infecting 18 goats and one R. turanicus tick, and 4 for a single isolate found in one sheep. Phylogenetic trees based on Msp1a partial sequences revealed that the N-terminal region of Msp1a protein appear to be relatively more informative phylogeographically compared to other markers especially according to countries. The presented data give a more detailed knowledge regarding the molecular phylogeny and the genetic diversity of A. ovis isolates occurring in different animal species and their associated ticks in Tunisia.

A Multiplex PCR Detection Assay for the Identification of Clinically Relevant Anaplasma Species in Field Blood Samples

The genus Anaplasma (Rickettsiales: Anaplasmataceae), which includes the species Anaplasma capra, Anaplasma bovis, Anaplasma ovis, and Anaplasma phagocytophilum, is responsible for a wide variety of infections in both human and veterinary health worldwide. Multiple infections with these four Anaplasma pathogens have been reported in many cases. We introduce a novel multiplex PCR for the simultaneous detection of A. capra, A. bovis, A. ovis, and A. phagocytophilum, based on species-specific primers against the groEL (A. capra and A. bovis), msp4 (A. ovis), and 16S rRNA (A. phagocytophilum) genes. To verify the specificity of the PCR reactions, we evaluated four sets of primers to analyze samples containing different blood pathogens. The sensitivity of the multiplex PCR was evaluated by amplifying 10-fold dilutions of total genomic DNA extracted from sheep blood infected with A. capra, A. bovis, A. ovis, or A. phagocytophilum. The reproducibility of the assay was evaluated by testing 10-fold dilutions of total genomic DNA extracted from sheep blood infected with these pathogens from 10⁰ to 10^–3 ng/μL per reaction in triplicate on three different days. A total of 175 field blood DNA samples were used to evaluate the reproducibility of multiplex PCR compared with the simplex PCRs. PCR primers used in this study were confirmed to be 100% species-specific using blood pathogens previously identified by other methods. The lower limit of detection of the multiplex PCR with good repeatability enabled the detection of A. capra, A. bovis, A. ovis and A. phagocytophilum at concentrations of 3 × 10^–5, 5 × 10^–7, 2 × 10^–5, and 7 × 10^–7 ng/μL, respectively. There was no significant difference between conventional and multiplex PCR protocols used to detect the four Anaplasma species (P > 0.05). The results of the multiplex PCR revealed that the A. capra groEL gene, the A. bovis groEL gene, the A. ovis msp4 gene, and the A. phagocytophilum 16S rRNA gene were reliable target genes for species identification in clinical isolates, being specific for each of the four target Anaplasma species. Our study provides an effective, sensitive, specific, and accurate tool for the rapid differential clinical diagnosis and epidemiological surveillance of Anaplasma pathogens in sheep and goats.

Human Spotted Fever Group Rickettsia Infecting Yaks (Bos grunniens) in the Qinghai-Tibetan Plateau Area

The Qinghai-Tibetan Plateau Area (QTPA) is a plateau with the highest average altitude, located in Northwestern China. There is a risk for interspecies disease transmission, such as spotted fever rickettsioses. However, information on the molecular characteristics of the spotted fever group (SFG) Rickettsia spp. in the area is limited. This study performed screenings, and detected the DNA of human pathogen, SFG Rickettsia spp., with 11.3% (25/222) infection rates in yaks (Bosgrunniens). BLASTn analysis revealed that the Rickettsia sequences obtained shared 94.3–100% identity with isolates of Rickettsia spp. from ticks in China. One Rickettsia sequence (MN536161) had 100% nucleotide identity to two R. raoultii isolates from Chinese Homo sapiens, and one isolate from Qinghai Dermacentorsilvarum. Meanwhile, another Rickettsia sequence (MN536157) shared 99.1–99.5% identity to one isolate from Dermacentor spp. in China. Furthermore, the phylogenetic analysis of SFG Rickettsia spp. ompA gene revealed that these two sequences obtained from yaks in the present study grouped with the R. slovaca and R. raoultii clades with isolates identified from Dermacentor spp. and Homo sapiens. Our findings showed the first evidence of human pathogen DNA, SFG Rickettsia spp., from animals, in the QTPA.

Molecular investigation of Anaplasma species in sheep from Heilongjiang Province, northeast China identified four Anaplasma species and a novel genotype of Anaplasma capra

Anaplasmosis poses a great threat to the livestock industry and human health in most tropical and subtropical regions of the world. This study investigated the presence of Anaplasma in sheep from Heilongjiang Province, northeastern China. A total of 341 blood samples were detected by PCR with species-specific primers based on the msp4 gene of Anaplasma ovis, 16S rRNA gene of Anaplasma phagocytophilum and Anaplasma bovis and gltA gene of Anaplasma capra. The results showed that Anaplasma infection was found in 103 (30.2%) of 341 sheep. The infection rates were 2.6%, 8.8%, 15.8% and 10.0% for A. ovis, A. phagocytophilum, A. bovis and A. capra in sheep, respectively. Co-infection involving two Anaplasma species was found in 25 sheep (8.0%), which were usually A. phagocytophilum and A. bovis (72.0%). Co-infection involving A. phagocytophilum, A. capra, A. ovis with zoonotic potential, was found in one sheep. Sequence analysis revealed that the isolates of A. ovis, A. bovis and A. phagocytophilum identified in sheep were closely related to those previously reported in ticks and other animal hosts. Phylogenetic analysis showed that A. capra could be classified into two distinct clusters based on the gltA gene and the isolates identified in sheep from this study were clustered in the A. capra genotype II, which was clearly distinct with the human isolates. The findings in this study report four Anaplasma species and a novel A. capra genotype in sheep from northeastern China, and improve our knowledge of Anaplasma, contributing to the control of ovine anaplasmosis.

Dogs as New Hosts for the Emerging Zoonotic Pathogen Anaplasma capra in China

Anaplasma capra is an emerging zoonotic tick-borne pathogen with a broad host range, including many mammals. Dogs have close physical interactions with humans and regular contact with the external environment. Moreover, they have been previously reported to be hosts of Anaplasma phagocytophilum, A. platys, A. ovis, and A. bovis. To confirm whether dogs are also hosts of A. capra, pathogen DNA was extracted from blood samples of 521 dogs, followed by PCR amplification of the citrate synthase (gltA) gene, heat shock protein (groEL) gene, and major surface protein 4 (msp4) gene of the A. capra. A total of 12.1% (63/521) of blood samples were shown to be A. capra-positive by PCR screening. No significant differences were observed between genders (P = 0.578) or types (P = 0.154) of dogs with A. capra infections. However, significantly higher A. capra infections occurred in dogs with regular contact with vegetation (P = 0.002), those aged over 10 years (P = 0.040), and during the summer season (P = 0.006). Phylogenetic analysis based on gltA, groEL, and msp4 sequences demonstrated that the isolates obtained in this study were clustered within the A. capra clade, and were distinct from other Anaplasma species. In conclusion, dogs were shown to be a host of the human pathogenic A. capra. Considering the affinity between dogs and humans and the zoonotic tick-borne nature of A. capra, dogs should be carefully monitored for the presence of A. capra.

Duplex TaqMan real-time PCR assay for simultaneous detection and quantification of Anaplasma capra and Anaplasma phagocytophilum infection

Anaplasma capra and A. phagocytophilum, two species of the family Anaplasmataceae, are zoonotic tick-borne obligate intracellular bacteria affecting wild and domestic ruminants, dogs, cats, horses and humans. A. capra and A. phagocytophilum infections have been steadily increasing in both number and geographic distribution, and the accurate diagnosis of these infections is challenging. This study aimed to develop a rapid, sensitive and reliable duplex real-time PCR assay for the specific detection and differentiation of these Anaplasma species. We designed primers and probes against the conserved regions of A. capra groEL and A. phagocytophilum 16S rRNA genes. A range of PCR-related parameters were evaluated such as the dosage of primers and probes, and annealing temperature. The specificity, sensitivity and repeatability of this assay were evaluated. Assay performance was further evaluated using samples collected from 124 goats in four regions of Henan, China. This set of samples was also tested using conventional PCR under conditions previously described. The developed duplex real-time PCR assay allowed the simultaneous detection of A. capra and A. phagocytophilum in a reasonably short time at levels as small as 10² copies/μL, respectively, with optimal specificity and reproducibility. In addition, this duplex real-time PCR assay is the first DNA-based method designed to detect A. capra and A. phagocytophilum, and will be valuable for timely diagnosis and treatment of these infections.

Molecular identification and characterization of Anaplasma capra and Anaplasma platys-like in Rhipicephalus microplus in Ankang, Northwest China

Background

Four species within Anaplasma genus are emerging zoonotic pathogens, which are transmitted by ticks and generate veterinary and public health concerns. Here, we performed a molecular survey of Anaplasma in Ankang, Northwest China.

Methods

Hard ticks were collected and identified using morphological and molecular methods. Human-pathogenic Anaplasma species were tested using nested polymerase chain reaction. The nearly complete rrs, gltA, and groEL genes sequences from revealed Anaplasma species were amplified and sequenced to determine their molecular characteristics and their phylogeny.

Results

All ticks collected in Ankang belonged to the Rhipicephalus microplus. Novel unclassified Anaplasma strains genetically related to A. platys and A. capra were detected in these ticks. Co-infection of these two organisms was also found. The novel unclassified Anaplasma strains identified in this study formed a distinct phylogenetic lineage based on the groEL gene and two lineages based on the gltA gene within A. platys and related strains group. The revealed A. capra strains identified in this study were most closely related to those detected in humans and other vertebrate animals.

Conclusion

We revealed the presence of A. capra, a novel human pathogens in R. microplus ticks in previously unrecognized endemic regions. We also detected a novel unclassified Anaplasma species genetically related to A. platys. The epidemiology of anaplasmosis caused by these two Anaplasma species in humans should be assessed in future studies.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4075-3) contains supplementary material, which is available to authorized users.