Identification of a granulocytotropic Ehrlichia species as the etiologic agent of human disease

Spatial patterns of Hyalomma marginatum-borne pathogens in the Occitanie region (France), a focus on the intriguing dynamics of Rickettsia aeschlimannii

Hyalomma marginatum is an invasive tick species recently established in mainland southern France. This tick is known to host a diverse range of human and animal pathogens. While information about the dynamics of these pathogens is crucial to assess disease risk and develop effective monitoring strategies, few data on the spatial dynamics of these pathogens are currently available. We collected ticks in 27 sites in the Occitanie region to characterize spatial patterns of H. marginatum-borne pathogens. Several pathogens have been detected: Theileria equi (9.2%), Theileria orientalis (0.2%), Anaplasma phagocytophilum (1.6%), Anaplasma marginale (0.8%), and Rickettsia aeschlimannii (87.3%). Interestingly, we found a spatial clustered distribution for the pathogen R. aeschlimannii between two geographically isolated areas with infection rates and bacterial loads significantly lower in Hérault/Gard departments (infection rate 78.6% in average) compared to Aude/Pyrénées-Orientales departments (infection rate 92.3% in average). At a smaller scale, R. aeschlimannii infection rates varied from one site to another, ranging from 29% to 100%. Overall, such high infection rates (87.3% on average) and the effective maternal transmission of R. aeschlimannii might suggest a role as a tick symbiont in H. marginatum. Further studies are thus needed to understand both the status and the role of R. aeschlimannii in H. marginatum ticks.IMPORTANCETicks are obligatory hematophagous arthropods that transmit pathogens of medical and veterinary importance. Pathogen infections cause serious health issues in humans and considerable economic loss in domestic animals. Information about the presence of pathogens in ticks and their dynamics is crucial to assess disease risk for public and animal health. Analyzing tick-borne pathogens in ticks collected in 27 sites in the Occitanie region, our results highlight clear spatial patterns in the Hyalomma marginatum-borne pathogen distribution and strengthen the postulate that it is essential to develop effective monitoring strategies and consider the spatial scale to better characterize the circulation of tick-borne pathogens.

Tick-Borne Bacterial Diseases in Europe: Threats to public health

BACKGROUND

Tick-borne diseases, caused by bacterial pathogens, pose a growing threat to public health in Europe. This paper provides an overview of the historical context of the discovery of the most impactful pathogens transmitted by ticks, including Borrelia burgdorferi sensu lato, Rickettsia spp., Anaplasma spp., Francisella spp., Ehrlichia spp., and Neoehrlichia mikurensis. Understanding the historical context of their discovery provides insight into the evolution of our understanding of these pathogens.

METHODS AND RESULTS

Systematic investigation of the prevalence and transmission dynamics of these bacterial pathogens is provided, highlighting the intricate relationships among ticks, host organisms, and the environment. Epidemiology is explored, providing an in-depth analysis of clinical features associated with infections. Diagnostic methodologies undergo critical examination, with a spotlight on technological advancements that enhance detection capabilities. Additionally, the paper discusses available treatment options, addressing existing therapeutic strategies and considering future aspects.

CONCLUSIONS

By integrating various pieces of information on these bacterial species, the paper aims to provide a comprehensive resource for researchers and healthcare professionals addressing the impact of bacterial tick-borne diseases in Europe. This review underscores the importance of understanding the complex details influencing bacterial prevalence and transmission dynamics to better combat these emerging public health threats.

Molecular surveillance of zoonotic pathogens from wild rodents in the Republic of Korea

BACKGROUND

Rodents are recognized as major reservoirs of numerous zoonotic pathogens and are involved in the transmission and maintenance of infectious diseases. Furthermore, despite their importance, diseases transmitted by rodents have been neglected. To date, there have been limited epidemiological studies on rodents, and information regarding their involvement in infectious diseases in the Republic of Korea (ROK) is still scarce.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated rodent-borne pathogens using nested PCR/RT-PCR from 156 rodents including 151 Apodemus agrarius and 5 Rattus norvegicus from 27 regions in eight provinces across the ROK between March 2019 and November 2020. Spleen, kidney, and blood samples were used to detect Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato group, Coxiella burnetii, Leptospira interrogans, and severe fever with thrombocytopenia syndrome virus (SFTSV). Of the 156 rodents, 73 (46.8%) were infected with Bartonella spp., 25 (16.0%) with C. burnetii, 24 (15.4%) with L. interrogans, 21 (13.5%) with A. phagocytophilum, 9 (5.8%) with SFTSV, and 5 (3.2%) with Borrelia afzelii. Co-infections with two and three pathogens were detected in 33 (21.1%) and 11 rodents (7.1%), respectively. A. phagocytophilum was detected in all regions, showing a widespread occurrence in the ROK. The infection rates of Bartonella spp. were 83.3% for B. grahamii and 16.7% for B. taylorii.

CONCLUSIONS/SIGNIFICANCE

To the best of our knowledge, this is the first report of C. burnetii and SFTSV infections in rodents in the ROK. This study also provides the first description of various rodent-borne pathogens through an extensive epidemiological survey in the ROK. These results suggest that rodents harbor various pathogens that pose a potential threat to public health in the ROK. Our findings provide useful information on the occurrence and distribution of zoonotic pathogens disseminated among rodents and emphasize the urgent need for rapid diagnosis, prevention, and control strategies for these zoonotic diseases.

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.

Opening the Black Box of Host Range, Vectorial Diversity, and Genetic Variants of Genus Anaplasma: The Contributing Factors Toward Its Zoonosis

Background: Genus Anaplasma of the family Anaplasmataceae possesses bacteria of hematopoietic origin, which are obligate intracellular Gram-negative bacteria transmitted mainly by tick vectors. The members of this group of infectious agents are not new as etiological agents of animal diseases worldwide. However, now, reports of their zoonotic potential have gained currency to study these pathogens. The emergence of new species of Anaplasma and the spread of existing species to new areas and hosts highlight the importance of monitoring and improving diagnostic and treatment options for zoonotic diseases caused by Anaplasma. Conclusion: This review focuses on the general and distinctive characteristics of Anaplasma spp., with particular emphasis on the novel species and their diverse spectrum of hosts as potential risk factors impacting its emerging zoonosis.

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Background

Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence.

Methods

We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis.

Results

Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, and Hyalomma rufipes ticks. We detected Ehrlichia ruminantium in all tissues of the four tick species, but Rickettsia aeschlimannii was only found in Hy. rufipes (all tissues). Rickettsia africae was highest in Am. gemma (62.5%), mainly in the hemolymph (45%) and less frequently in the midgut (27.5%) and lowest in Rh. pulchellus (29.4%), where midgut and hemolymph detection rates were 17.6% and 11.8%, respectively. Similarly, in Hy. dromedarii, R. africae was mainly detected in the midgut (41.7%) but was absent in the hemolymph. Rickettsia africae was not detected in Hy. rufipes. No Coxiella, Theileria, or Babesia spp. were detected in this study.

Conclusions

The tissue-specific localization of R. africae, found mainly in the hemolymph of Am. gemma, is congruent with the role of this tick species as its transmission vector. Thus, occurrence of TBPs in the hemolymph could serve as a predictor of vector competence of TBP transmission, especially in comparison to detection rates in the midgut, from which they must cross tissue barriers to effectively replicate and disseminate across tick tissues. Further studies should focus on exploring the distribution of TBPs within tick tissues to enhance knowledge of TBP epidemiology and to distinguish competent vectors from dead-end hosts.

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.

Human Tick-Borne Diseases and Advances in Anti-Tick Vaccine Approaches: A Comprehensive Review

This comprehensive review explores the field of anti-tick vaccines, addressing their significance in combating tick-borne diseases of public health concern. The main objectives are to provide a brief epidemiology of diseases affecting humans and a thorough understanding of tick biology, traditional tick control methods, the development and mechanisms of anti-tick vaccines, their efficacy in field applications, associated challenges, and future prospects. Tick-borne diseases (TBDs) pose a significant and escalating threat to global health and the livestock industries due to the widespread distribution of ticks and the multitude of pathogens they transmit. Traditional tick control methods, such as acaricides and repellents, have limitations, including environmental concerns and the emergence of tick resistance. Anti-tick vaccines offer a promising alternative by targeting specific tick proteins crucial for feeding and pathogen transmission. Developing vaccines with antigens based on these essential proteins is likely to disrupt these processes. Indeed, anti-tick vaccines have shown efficacy in laboratory and field trials successfully implemented in livestock, reducing the prevalence of TBDs. However, some challenges still remain, including vaccine efficacy on different hosts, polymorphisms in ticks of the same species, and the economic considerations of adopting large-scale vaccine strategies. Emerging technologies and approaches hold promise for improving anti-tick vaccine development and expanding their impact on public health and agriculture.

Epidemiological and phylogenetic characteristics of emerging Anaplasma capra: A systematic review with modeling analysis

Anaplasma capra, an emerging tick-borne pathogen, has caused a lot of concern since initially recognized in goats and patients in China in 2015, and has been reported in a wide range of domestic and wild animals as well as ticks worldwide, posing a threat to public health. In this systematic review, we established a comprehensive database to acquire the distribution and prevalence status of this pathogen, and collected all sequences of A. capra to summarize the details of genetic diversity by phylogenetic analysis. We also predicted the possible global distribution of A. capra by using ecological niche model. A. capra has been known to distribute in 18 countries across Asia, Europe and Africa. A total of 19 species of mammals from seven families have been reported as hosts, and domestic ruminants including goats, sheep and cattle were the major hosts. At least 8 tick species of 4 genera have been reported to carry A. capra, and Haemaphysalis longicornis was most commonly infected. Sheep and Rhipicephalus microplus had the highest positive rates among animals and ticks. Phylogenetic analysis based on gltA and groEL genes revealed that A. capra could primarily be divided into two clusters related to geographic location and animal hosts. The predictive model showed that the most suitable habitats for presence of A. capra were mainly located in Asia and eastern Europe. These cumulative data regarding A. capra of our study lay a foundation for the subsequent exploration of this emerging tick-borne pathogen.

Altered Mental Status on Top of Anaplasmosis-Induced Severe Rhabdomyolysis: A Rare Clinical Presentation

Human granulocytic anaplasmosis (HGA) is a disease caused by tick-borne infection of Anaplasma phagocytophilum. The typical symptoms are fever, malaise, and body aches accompanied by abnormal blood tests such as leukopenia, thrombocytopenia, and transaminitis. Some rare complications may occur, especially in patients living in heavily wooded areas, with a mean age of 70 years. We present a case of a 67-year-old male who was admitted for lower abdominal pain, fever, and diarrhea with derangement of his blood tests. Despite treatment, his condition deteriorated and complicated rhabdomyolysis and acute kidney dysfunction. Empiric treatment including doxycycline was initiated while waiting for the infection blood work results. PCR came back positive for HGA. Empiric therapy was narrowed down to doxycycline for 14 days, and the patient's condition began to improve gradually and steadily. Aggressive hydration markedly improved rhabdomyolysis and, in turn, kidney function. Our case underscores the importance of considering HGA in ambiguous clinical scenarios and highlights the value of early diagnosis, empiric treatment, and intravenous hydration, especially in the presence of rhabdomyolysis.

Host-pathogen associations revealed by genotyping of European strains of Anaplasma phagocytophilum to describe natural endemic cycles

BACKGROUND

The zoonotic intracellular alpha-proteobacterium Anaplasma phagocytophilum is a tick-transmitted pathogen. The associations between vertebrate reservoirs and vectors are described as wide-ranging, and it was previously shown that the pathogenicity of A. phagocytophilum differs depending on the combination of pathogen variant and infected host species. This leads to the question of whether there are variations in particular gene loci associated with different virulence. Therefore, this study aims at clarifying existing host-variant combinations and detecting possible reservoir hosts. To understand these interactions, a complex toolset for molecular epidemiology, phylogeny and network theory was applied.

METHODS

Sequences of up to four gene loci (msp4, msp2, groEL and 16S rRNA) were evaluated for different isolates from variable host species, including, for example, dogs, cattle and deer. Variant typing was conducted for each gene locus individually, and combinations of different gene loci were analysed to gain more detailed information about the genetic plasticity of A. phagocytophilum. Results were displayed as minimum spanning nets and correlation nets.

RESULTS

The highest diversity of variants for all gene loci was observed in roe deer. In cattle, a reduced number of variants for 16S rRNA [only 16S-20(W) and 16S-22(Y)] but multiple variants of msp4 and groEL were found. For dogs, two msp4 variants [m4-20 and m4-2(B/C)] were found to be linked to different variants of the other three gene loci, creating two main combinations of gene loci variants. Cattle are placed centrally in the minimum spanning net analyses, indicating a crucial role in the transmission cycles by possibly bridging the vector-wildlife cycle to infections of humans and domestic animals. The minimum spanning nets confirmed previously described epidemiological cycles of the bacterium in Europe, showing separation of variants originating from wildlife animals only and a set of variants shared by wild and domestic animals.

CONCLUSIONS

In this comprehensive study of 1280 sequences, we found a high number of gene variants only occurring in specific hosts. Additionally, different hosts show unique but also shared variant combinations. The use of our four gene loci expand the knowledge of host-pathogen interactions and may be a starting point to predict future spread and infection risks of A. phagocytophilum in Europe.

Multiple Ehrlichia chaffeensis genes critical for persistent infection in a vertebrate host are identified as nonessential for its growth in the tick vector; Amblyomma americanum

Ehrlichia chaffeensis is a tick-transmitted monocytic ehrlichiosis agent primarily causing the disease in people and dogs. We recently described the development and characterization of 55 random mutations in E. chaffeensis, which aided in defining the critical nature of many bacterial genes for its growth in a physiologically relevant canine infection model. In the current study, we tested 45 of the mutants for their infectivity ability to the pathogen's tick vector; Amblyomma americanum. Four mutations resulted in the pathogen's replication deficiency in the tick, similar to the vertebrate host. Mutations causing growth defects in both vertebrate and tick hosts included in genes coding for a predicted alpha/beta hydrolase, a putative dicarboxylate amino acid:cation symporter, a T4SS protein, and predicted membrane-bound proteins. Three mutations caused the bacterial defective growth only in the tick vector, which represented putative membrane proteins. Ten mutations causing no growth defect in the canine host similarly grew well in the tick vector. Mutations in 28 genes/genomic locations causing E. chaffeensis growth attenuation in the canine host were recognized as non-essential for its growth in the tick vector. The tick non-essential genes included genes coding for many metabolic pathway- and outer membrane-associated proteins. This study documents novel vector- and host-specific differences in E. chaffeensis for its functional gene requirements.

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 Anaplasma, Ehrlichia and Rickettsia Pathogens in Ticks Collected from Humans in the Republic of Korea, 2021

Tick-borne pathogens (TBPs), transmitted by the bites of ticks, are of great medical and veterinary importance. They include bacteria, viruses, and protozoan parasites. To provide fundamental data on the risk of tick contact and public health strategies, we aimed to perform a molecular investigation on four tick-borne bacterial pathogens in ticks collected from humans across the Republic of Korea (ROK) in 2021. In total, 117 ticks were collected, including Haemaphysalis longicornis (56.4%), Amblyomma testudinarium (26.5%), Ixodes nipponensis (8.5%), H. flava (5.1%), and I. persulcatus (0.9%). Among the ticks, 20.5% (24/117) contained tick-borne bacterial pathogens, with infection rates of 17.9% for Rickettsia (Candidatus Rickettsia jingxinensis, R. tamurae, R. monacensis, and Candidatus Rickettsia tarasevichiae), 2.5% for Anaplasma (A. phagocytophilum, A. capra, and A. bovis), and 0.9% for Ehrlichia (Ehrlichia sp.). Additionally, the co-detection rate for R. monacensis and A. phagocytophilum was 0.9%. To our knowledge, this is the first report of A. capra and A. bovis detection in ticks collected from humans in the ROK. This study contributes to the understanding of the potential risk of tick contact and provides fundamental data for establishing a public health strategy for tick-borne disease management in the ROK.

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.

Molecular Detection and Phylogenetic Characterization of Anaplasma spp. in Dogs from Hainan Province/Island, China

Anaplasmosis is a serious infection which is transmitted by ticks and mosquitos. There are very few reports and studies that have been carried out to understand the prevalence, distribution, and epidemiological profile of Anaplasma spp. infection in dogs in Hainan province/island. In the present study, we have tried to understand the prevalence, distribution, and occurrence of Anaplasma spp. infections in dogs (n = 1051) in Hainan Island/Province to establish a surveillance-based study. The confirmed positive samples by Polymerase chain reaction (PCR) were subjected to capillary sequencing for further strain-specific confirmation, followed by the construction of phylogenetic trees to determine their genetic relations. Various statistical tools were used to analyze related risk factors. There were three species of Anaplasma detected from the Hainan region; namely, A. phagocytophilum, A. bovis, and A. platys. The overall prevalence of Anaplasma is 9.7% (102/1051). A. phagocytopihum was prevalent in 1.0% of dogs (11/1051), A. bovis was found in 2.7% of dogs (28/1051), and A. platys in 6.0% of dogs (63/1051). Our surveillance-based study conducted to understand the occurrence and distribution pattern of Anaplasma spp. in Hainan will help in designing effective control measures along with management strategies so as to treat and control the infection in the area.

Innate immunity in rickettsial infections

Rickettsial agents are a diverse group of alpha-proteobacteria within the order Rickettsiales, which possesses two families with human pathogens, Rickettsiaceae and Anaplasmataceae. These obligate intracellular bacteria are most frequently transmitted by arthropod vectors, a first step in the pathogens' avoidance of host cell defenses. Considerable study of the immune responses to infection and those that result in protective immunity have been conducted. Less study has focused on the initial events and mechanism by which these bacteria avoid the innate immune responses of the hosts to survive within and propagate from host cells. By evaluating the major mechanisms of evading innate immunity, a range of similarities among these bacteria become apparent, including mechanisms to escape initial destruction in phagolysosomes of professional phagocytes, those that dampen the responses of innate immune cells or subvert signaling and recognition pathways related to apoptosis, autophagy, proinflammatory responses, and mechanisms by which these microbes attach to and enter cells or those molecules that trigger the host responses. To illustrate these principles, this review will focus on two common rickettsial agents that occur globally, Rickettsia species and Anaplasma phagocytophilum.

Circulation of four species of Anaplasmataceae bacteria in ticks in Harbin, northeastern China

Ticks play an important role in the evolution and transmission of Anaplasmataceae bacteria which are agents of emerging infectious diseases. In this study, a total of 1286 adult ticks belonging to five species were collected from cattle, goats, horses and vegetation in Harbin area, Heilongjiang province, northeastern China. The tick-borne Anaplasmataceae bacteria were identified by amplifying and sequencing the 16S rRNA (rrs) and heat shock protein-60 encoding (groEL) genes. The results showed that Ixodes persulcatus was dominant (38.8%, 499/1283) among the five tick species, and Anaplasmataceae bacteria were detected in all tick species with an overall prevalence of 7.4%. Four species of Anaplasmataceae bacteria (Anaplasma phagocytophilum, Anaplasma ovis, Anaplasma bovis, and "Candidatus Neoehrlichia mikurensis"), which are pathogenic to humans and/or animals, were identified from tick samples by phylogenetic analyzes of the rrs and groEL gene sequences. Interestingly, the cluster 1 strains were first identified in Asian, and a novel cluster was also detected in this study. These data revealed the genetic diversity of Anaplasmataceae bacteria circulating in ticks in Harbin area, highlighting the need to investigate these tick-borne pathogens and their risks to human and animal health.

Clinically differential diagnosis of human granulocytic anaplasmosis and severe fever with thrombocytopenia syndrome

This study analyzed HGA and SFTS in patients with suspected tick-borne infection by focusing on key differences that clinicians can easily recognize. A retrospective analysis was performed on confirmed patients with HGA or SFTS in 21 Korean hospitals from 2013 to 2020. A scoring system was developed by multivariate regression analysis and accuracy assessment of clinically easily discriminable parameters was performed. The multivariate logistic regression analysis revealed that sex (especially male sex) (odds ratio [OR] 11.45, P = 0.012), neutropenia (< 1500) (OR 41.64, P < 0.001), prolonged activated partial thromboplastin time (OR 80.133, P < 0.001), and normal C-reactive protein concentration (≤ 1.0 mg/dL; OR 166.855, P = 0.001) were significantly associated with SFTS but not with HGA. Each factor, such as meaningful variables, was given 1 point, and a receiver-operating characteristic curve with a cutoff value (> 1) in a 5-point scoring system (0-4 points) was analyzed to evaluate the accuracy of differentiation between HGA and SFTS. The system showed 94.5% sensitivity, 92.6% specificity, and an area under the receiver-operating characteristic curve of 0.971 (0.949-0.9). Where HGA and SFTS are endemic, the scoring system based on these four parameters such as sex, neutrophil count, activated partial thromboplastin time, and C-reactive protein concentration will facilitate the differential diagnosis of HGA and SFTS in the emergency room in patients with suspected tick-borne infectious diseases.

Distribution and Prevalence of Anaplasmataceae, Rickettsiaceae and Coxiellaceae in African Ticks: A Systematic Review and Meta-Analysis

In Africa, ticks continue to be a major hindrance to the improvement of the livestock industry due to tick-borne pathogens that include Anaplasma, Ehrlichia, Rickettsia and Coxiella species. A systemic review and meta-analysis were conducted here and highlighted the distribution and prevalence of these tick-borne pathogens in African ticks. Relevant publications were searched in five electronic databases and selected using inclusion/exclusion criteria, resulting in 138 and 78 papers included in the qualitative and quantitative analysis, respectively. Most of the studies focused on Rickettsia africae (38 studies), followed by Ehrlichia ruminantium (27 studies), Coxiella burnetii (20 studies) and Anaplasma marginale (17 studies). A meta-analysis of proportions was performed using the random-effects model. The highest prevalence was obtained for Rickettsia spp. (18.39%; 95% CI: 14.23–22.85%), R. africae (13.47%; 95% CI: 2.76–28.69%), R. conorii (11.28%; 95% CI: 1.77–25.89%), A. marginale (12.75%; 95% CI: 4.06–24.35%), E. ruminantium (6.37%; 95% CI: 3.97–9.16%) and E. canis (4.3%; 95% CI: 0.04–12.66%). The prevalence of C. burnetii was low (0%; 95% CI: 0–0.25%), with higher prevalence for Coxiella spp. (27.02%; 95% CI: 10.83–46.03%) and Coxiella-like endosymbionts (70.47%; 95% CI: 27–99.82%). The effect of the tick genera, tick species, country and other variables were identified and highlighted the epidemiology of Rhipicephalus ticks in the heartwater; affinity of each Rickettsia species for different tick genera; dominant distribution of A. marginale, R. africae and Coxiella-like endosymbionts in ticks and a low distribution of C. burnetii in African hard ticks.

Associations of Anaplasma phagocytophilum Bacteria Variants in Ixodes scapularis Ticks and Humans, New York, USA

Anaplasmosis, caused by the tickborne bacterium Anaplasma phagocytophilum, is an emerging public health threat in the United States. In the northeastern United States, the blacklegged tick (Ixodes scapularis) transmits the human pathogenic genetic variant of A. phagocytophilum (Ap-ha) and a nonpathogenic variant (Ap-V1). New York has recently experienced a rapid and geographically focused increase in cases of anaplasmosis. We analyzed A. phagocytophilum-infected I. scapularis ticks collected across New York during 2008-2020 to differentiate between variants and calculate an entomological risk index (ERI) for each. Ap-ha ERI varied between regions and increased in all regions during the final years of the study. Space-time scan analyses detected expanding clusters of Ap-ha located within documented anaplasmosis hotspots. Ap-ha ERI was more positively correlated with anaplasmosis incidence than non-genotyped A. phagocytophilum ERI. Our findings help elucidate the relationship between the spatial ecology of A. phagocytophilum variants and anaplasmosis.

Worldwide meta-analysis on Anaplasma phagocytophilum infections in animal reservoirs: Prevalence, distribution and reservoir diversity

A wide range of vertebrate species are competent reservoirs of Anaplasma phagocytophilum, where the pathogen is maintained in the enzootic cycle and transmitted to humans through activities of tick vectors. An insight into the role and diversity of these reservoirs is vital in understanding the epidemiology of this pathogen. Here, we determined the prevalence, distribution and reservoir diversity of A. phagocytophilum using a systematic review and meta-analysis. Data pooling was performed by the random-effects model, heterogeneity was assessed by the Cochran's Q-test and publication bias by Egger's regression test. Eighty-nine studies from 33 countries across 5 continents revealed A. phagocytophilum pooled prevalence of 15.18% (95% CI: 11.64, 19.57). Continental estimates varied significantly (p < 0.0001), with a range of 2.88% (95% CI: 0.25, 26.20) in South America to 19.91% (95% CI: 13.57, 28.24) in Europe. Country-based estimates ranged between 2.93% (95% CI: 1.17, 7.16) in Slovakia and 71.58% (95% CI: 25.91, 94.77) in Norway. Studies on A. phagocytophilum were concentrated in Europe (51.69%; 46/89) by continent and the USA (22.47%; 20/89) by country. Prevalence in wildlife (17.64%; 95% CI: 12.21-28.59) was significantly higher (p < 0.001) than that among domestic animals (10.68%; 95% CI: 6.61-16.83). Diverse species of wildlife, domestic animals and birds were infected by A. phagocytophilum. To curtail the public health, veterinary and economic consequences of A. phagocytophilum infections, we recommend an all-inclusive epidemiological approach that targets the human, animal and environmental components of the disease.

The Biological and Ecological Features of Northbound Migratory Birds, Ticks, and Tick-Borne Microorganisms in the African-Western Palearctic

Identifying the species that act as hosts, vectors, and vehicles of vector-borne pathogens is vital for revealing the transmission cycles, dispersal mechanisms, and establishment of vector-borne pathogens in nature. Ticks are common vectors for pathogens causing human and animal diseases, and they transmit a greater variety of pathogenic agents than any other arthropod vector group. Ticks depend on the movements by their vertebrate hosts for their dispersal, and tick species with long feeding periods are more likely to be transported over long distances. Wild birds are commonly parasitized by ticks, and their migration patterns enable the long-distance range expansion of ticks. The African-Palearctic migration system is one of the world's largest migrations systems. African-Western Palearctic birds create natural links between the African, European, and Asian continents when they migrate biannually between breeding grounds in the Palearctic and wintering grounds in Africa and thereby connect different biomes. Climate is an important geographical determinant of ticks, and with global warming, the distribution range and abundance of ticks in the Western Palearctic may increase. The introduction of exotic ticks and their microorganisms into the Western Palearctic via avian vehicles might therefore pose a greater risk for the public and animal health in the future.

Perspectives of vector management in the control and elimination of vector-borne zoonoses

The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.

Rickettsial pathogen inhibits tick cell death through tryptophan metabolite mediated activation of p38 MAP kinase

Anaplasma phagocytophilum modulates various cell signaling pathways in mammalian cells for its survival. In this study, we report that A. phagocytophilum modulates tick tryptophan pathway to activate arthropod p38 MAP kinase for the survival of both this bacterium and its vector host. Increased level of tryptophan metabolite, xanthurenic acid (XA), was evident in A. phagocytophilum-infected ticks and tick cells. Lower levels of cell death markers and increased levels of total and phosphorylated p38 MAPK was noted in A. phagocytophilum-infected ticks and tick cells. Treatment with XA increased phosphorylated p38 MAPK levels and reduced cell death in A. phagocytophilum-infected tick cells. Furthermore, treatment with p38 MAPK inhibitor affected bacterial replication, decreased phosphorylated p38 MAPK levels and increased tick cell death. However, XA reversed these effects. Taken together, we provide evidence that rickettsial pathogen modulates arthropod tryptophan and p38 MAPK pathways to inhibit cell death for its survival in ticks.

Seroprevalence of tick-borne diseases in the Northwest Federal District of the Russian Federation

Introduction. Knowledge about tick-borne disease (TBD) distribution is necessary to improve prevention, whereas detection of human serum IgG antibodies against relevant pathogens is a method for monitoring TBD prevalence in local population. The study objective was to estimate seroprevalence of IgG antibodies against tick-borne encephalitis virus (TBEV), Borrelia burgdorferi sensu lato, Coxiella burnetii, Anaplasma phagocytophilum, and Ehrlichia chaffeensis/E. muris in healthy residents from the five territories of the Northwestern Federal District of the Russian Federation (Arkhangelsk Oblast, Leningrad Oblast, Pskov Oblast, the Republic of Komi and the Republic of Karelia). Materials and methods. In 20172019, a total of 1244 serum samples from healthy residents, not vaccinated against TBDs or other flavivirus-caused infections was studied by ELISA. Results. 21.7% of the sera samples contained IgG antibodies against a single TBD pathogen, whereas 2.1% showed signs of coinfection with two or more pathogens. The most common were IgG antibodies against TBEV (5 territories, 12.2%), followed by Borrelia burgdorferi sensu lato (5 territories, 3.5%), C. burnetii (4 territories, 2.9%), Anaplasma phagoсytophilum (3 territories, 1.6%), E. chaffeensis/E. muris (5 territories, 1.5%). The IgG antibodies were more common in men (55.2%) than in women (44.8%), being found virtually evenly in age-independent manner (from juniors under 18 to seniors over 60). Conclusion. The results of this first comprehensive serosurveillance study in the Northwestern Federal District of the Russian Federation assessing serum IgG antibodies against tick-borne diseases indicate a wide distribution of such pathogens. Moreover, infections caused by C. burnetii, Anaplasma phagocytophilum, and Ehrlichia chaffeensis/E. muris might be highly underdiagnosed.

Diversity and geographic distribution of rickettsial agents identified in brown dog ticks from across the United States

Rhipicephalus sanguineus sensu lato, or brown dog ticks, transmit a variety of pathogens of veterinary and public health importance globally. Pathogens vectored by brown dog ticks and identified in the United States include Babesia vogeli, Ehrlichia canis, and several spotted fever group Rickettsia spp. (SFGR). Due to the challenge of collecting canine blood samples nationwide to screen for exposure to these pathogens, we took an indirect approach and tested brown dog ticks for molecular evidence of infection. Brown dog ticks (616 adults and 65 nymphs) collected from dogs and cats across the nation were tested by separate PCR assays detecting Babesia spp., E. canis, and SFGR. While no Babesia sp. was found, we identified rickettsial agents in 3.5% (24/681; 95% CI 2.4-5.2%) of the ticks. Pathogens and related organisms detected in ticks included E. canis (n = 1), Rickettsia amblyommatis (n = 3), Rickettsia massiliae (n = 11), Rickettsia monacensis (n = 3), Rickettsia montanensis (n = 5), and an undefined Rickettsia species (n = 1). These data demonstrate a wider geographic distribution of R. massiliae than previously known, and to the authors' knowledge, reports R. monacensis in brown dog ticks for the first time. Due to the close association that brown dog ticks have with domestic dogs and humans, more research is needed to understand the full array of organisms, some of which are zoonotic, potentially transmitted by this widespread tick complex.

Lice and lice-borne diseases in humans in Africa: a narrative review

Lice are host-specific insects. Human lice include Pediculus humanus humanus (body lice) which are known to be vectors of serious human bacterial infectious diseases including epidemic typhus, relapsing fever, trench fever and plague; Pediculus humanus capitis (head lice) that frequently affect children; and Pthirus pubis, commonly known as crab lice. In Africa, human infections transmitted by lice remained poorly known and therefore, underestimated, perhaps due to the lack of diagnostic tools and professional knowledge. In this paper we review current knowledge of the microorganisms identified in human lice in the continent of Africa, in order to alert health professionals to the importance of recognising the risk of lice-related diseases.

Human Granulocytic Anaplasmosis

Human granulocytic anaplasmosis (HGA) is a bacterial infection caused by Anaplasma phagocytophilum and transmitted by the bite of the black-legged (deer tick) in North America. Its incidence is increasing. HGA can be transmitted after 24 to 48 hours of tick attachment. The incubation period is 5 to 14 days after a tick bite. Symptoms include fever, chills, headache, and myalgia. Complications include shock, organ dysfunction, and death. Mortality is less than 1% with appropriate treatment. Doxycycline is first line treatment for all ages. Start it empirically if symptoms and risk factors suggest HGA. PCR is the confirmatory test of choice.

Risk of tick-borne pathogen spillover into urban yards in New York City

BACKGROUND

The incidence of tick-borne disease has increased dramatically in recent decades, with urban areas increasingly recognized as high-risk environments for exposure to infected ticks. Green spaces may play a key role in facilitating the invasion of ticks, hosts and pathogens into residential areas, particularly where they connect residential yards with larger natural areas (e.g. parks). However, the factors mediating tick distribution across heterogeneous urban landscapes remain poorly characterized.

METHODS

Using generalized linear models in a multimodel inference framework, we determined the residential yard- and local landscape-level features associated with the presence of three tick species of current and growing public health importance in residential yards across Staten Island, a borough of New York City, in the state of New York, USA.

RESULTS

The amount and configuration of canopy cover immediately surrounding residential yards was found to strongly predict the presence of Ixodes scapularis and Amblyomma americanum, but not that of Haemaphysalis longicornis. Within yards, we found a protective effect of fencing against I. scapularis and A. americanum, but not against H. longicornis. For all species, the presence of log and brush piles strongly increased the odds of finding ticks in yards.

CONCLUSIONS

The results highlight a considerable risk of tick exposure in residential yards in Staten Island and identify both yard- and landscape-level features associated with their distribution. In particular, the significance of log and brush piles for all three species supports recommendations for yard management as a means of reducing contact with ticks.

Human Granulocytic Anaplasmosis-A Systematic Review of Published Cases

Anaplasma phagocytophilum is an emerging, Gram-negative, obligate intracellular pathogen that is transmitted by a tick vector. Human infection ranges from asymptomatic to severe disease that can present with pancytopenia, multiorgan failure, and death. The aim of this systematic review is to analyze case reports and case series reported over the last two decades in peer-reviewed journals indexed in the Medline/PubMed database according to the PRISMA guidelines. We found 110 unique patients from 88 case reports and series. The most common mode of transmission was tick bite (60.9%), followed by blood transfusion (8.2%). Infection was acquired by blood transfusion in nearly half (42%) of the immunocompromised patients. Most patients reported fever (90%), followed by constitutional (59%) and gastrointestinal symptoms (56%). Rash was present in 17% of patients, much higher than in previous studies. Thrombocytopenia was the most common laboratory abnormality (76%) followed by elevated aspartate aminotransferase (AST) (46%). The diagnosis was most commonly established using whole-blood polymerase chain reaction (PCR) in 76% of patients. Coinfection rate was 9.1% and Borrelia burgdorferi was most commonly isolated in seven patients (6.4%). Doxycycline was used to treat 70% of patients but was only used as an empiric treatment in one-third of patients (33.6%). The overall mortality rate was 5.7%, and one patient died from trauma unrelated to HGA. The mortality rates among immunocompetent and immunocompromised patients were 4.2% (n = 4/95) and 18.2% (n = 2/11), respectively. Four of the six patients who died (66.6%) received appropriate antibiotic therapy. Among these, doxycycline was delayed by more than 48 h in two patients.

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.

Molecular Detection of Anaplasma phagocytophilum and Ehrlichia Species in Ticks Removed from Humans in the Republic of Korea

Human granulocytic anaplasmosis (HGA) and human monocytic ehrlichiosis (HME) are zoonotic tick-borne diseases transmitted via tick bites. To determine the state of human Anaplasma and Ehrlichia infections caused by tick bites in the Republic of Korea (ROK), we conducted a nationwide investigation of human cases of tick bites in 2020. A total of 180 ticks were obtained, comprising Haemaphysalis longicornis (70.0%), Amblyomma testudinarium (17.8%), Ixodes nipponensis (6.1%), H. flava (4.4%), and I. persulcatus (1.7%). In three cases (1.7%; 95% CI: 0.3-4.9), A. phagocytophilum was detected in Ixodes ticks using primers for Anaplasma-specific genes (16s rRNA, ankA, and msp4). Conversely, Ehrlichia sp. was only detected in H. longicornis, in two cases (1.1%; 95% CI: 0.1-4.0). To the best of our knowledge, this is the first record of Ehrlichia sp. in ticks parasitizing humans in the ROK. As concerns remain about the possibility of HGA and HME transmission, continuous monitoring and management of the pathogens and vectors are necessary.

Trypanosoma cruzi and Other Vector-Borne Infections in Shelter Dogs in Two Counties of Oklahoma, United States

Trypanosoma cruzi is an emerging zoonotic vector-borne parasite infecting dogs and other mammals in the United States. In this study we evaluated shelter dogs in one northeastern and one southeastern county in Oklahoma for prevalence of exposure to T. cruzi. Dogs were tested for antibodies against T. cruzi using the Chagas STAT PAK^® assay and for T. cruzi in circulation by PCR. In addition, dogs were tested for evidence of infection with other vector-borne organisms using the SNAP^® 4Dx^® Plus Test and PCR. Overall, 26 of 197 (13.2%) shelter dogs had detectable antibodies against T. cruzi and 3 of 189 (1.6%) dogs were PCR positive. In addition, we found that 42 of 197 (21.3%) shelter dogs had evidence of exposure to or were infected with at least one vector-borne agent other than T. cruzi based on serology and/or PCR; 9 of 42 (21.4%) of these dogs were also positive for T. cruzi antibodies. Other infections identified in dogs included Anaplasma phagocytophilum, Anaplasma platys, Babesia sp. (Coco), Dirofilaria immitis, Ehrlichia canis, Ehrlichia chaffeensis, Ehrlichia ewingii, and Hepatozoon americanum. This study serves to boost state-wide veterinary and public health awareness of T. cruzi and other vector-borne pathogens infecting shelter dogs in Oklahoma. Results indicate the need for more comprehensive screening of shelter dogs in Oklahoma for exposure to vector-borne agents to enhance surveillance and to identify dogs in need of additional specific veterinary care.

Detection of Tick-Borne Bacterial and Protozoan Pathogens in Ticks from the Zambia–Angola Border

Tick-borne diseases (TBDs), including emerging and re-emerging zoonoses, are of public health importance worldwide; however, TBDs tend to be overlooked, especially in countries with fewer resources, such as Zambia and Angola. Here, we investigated Rickettsia, Anaplasmataceae, and Apicomplexan pathogens in 59 and 96 adult ticks collected from dogs and cattle, respectively, in Shangombo, a town at the Zambia–Angola border. We detected Richkettsia africae and Rickettsia aeschilimannii in 15.6% of Amblyomma variegatum and 41.7% of Hyalomma truncatum ticks, respectively. Ehrlichia minasensis was detected in 18.8% of H. truncatum, and Candidatus Midichloria mitochondrii was determined in Hyalomma marginatum. We also detected Babesia caballi and Theileria velifera in A. variegatum ticks with a 4.4% and 6.7% prevalence, respectively. In addition, Hepatozoon canis was detected in 6.5% of Rhipicephalus lunulatus and 4.3% of Rhipicephalus sanguineus. Coinfection of R. aeshilimannii and E. minasensis were observed in 4.2% of H. truncatum. This is the first report of Ca. M. mitochondrii and E. minasensis, and the second report of B. caballi, in the country. Rickettsia africae and R. aeschlimannii are pathogenic to humans, and E. minasensis, B. caballi, T. velifera, and H. canis are pathogenic to animals. Therefore, individuals, clinicians, veterinarians, and pet owners should be aware of the distribution of these pathogens in the area.

Anaplasma phagocytophilum in Marmota himalayana

Background

Human granulocytic anaplasmosis is a tick-borne zoonotic disease caused by Anaplasma phagocytophilum. Coinfections with A. phagocytophilum and other tick-borne pathogens are reported frequently, whereas the relationship between A. phagocytophilum and flea-borne Yersnia pestis is rarely concerned.

Results

A. phagocytophilum and Yersnia pestis were discovered within a Marmota himalayana found dead in the environment, as determined by 16S ribosomal rRNA sequencing. Comparative genomic analyses of marmot-derived A. phagocytophilum isolate demonstrated its similarities and a geographic isolation from other global strains. The 16S rRNA gene and GroEL amino acid sequence identity rates between marmot-derived A. phagocytophilum (JAHLEX000000000) and reference strain HZ (CP000235.1) are 99.73% (1490/1494) and 99.82% (549/550), respectively. 16S rRNA and groESL gene screenings show that A. phagocytophilum is widely distributed in marmots; the bacterium was more common in marmots found dead (24.59%, 15/61) than in captured marmots (19.21%, 29/151). We found a higher Y. pestis isolation rate in dead marmots harboring A. phagocytophilum than in those without it (² = 4.047, p < 0.05). Marmot-derived A. phagocytophilum was able to live in L929 cells and BALB/c mice but did not propagate well.

Conclusions

In this study, A. phagocytophilum was identified for the first time in Marmota himalayana, a predominant Yersinia pestis host. Our results provide initial evidence for M. himalayana being a reservoir for A. phagocytophilum; moreover, we found with the presence of A. phagocytophilum, marmots may be more vulnerable to plague. Humans are at risk for co-infection with both pathogens by exposure to such marmots.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08557-x.

[Role of systemic infections in canine kidney diseases]

Kidney diseases represent a common problem as well as a frequent cause of death in dogs. Infectious agents may be responsible for glomerulopathies and acute kidney injuries. Many infections commonly associated with the development of immune complex glomerulonephritis in central and southern Europe are important as travel-associated diseases in Germany. These include leishmaniosis, dirofilariosis, and ehrlichiosis. Rarely, anaplasmosis, hepatozoonosis, Lyme disease as well as babesiosis caused by small Babesia spp. are detected as cause of canine immune complex glomerulonephritis in Germany. Leptospirosis, canine infectious hepatitis, and babesiosis caused by large Babesia spp. may be responsible for the development of acute kidney injuries associated with tubulointerstitial nephritis. Therefore, further diagnostics aiming at identifying potentially causative infectious agents in dogs with renal disease is important for both prognosis and therapy of the patient.

<i>Anaplasma bovis</i> Infection in Fever and Thrombocytopenia Patients — Anhui Province, China, 2021

What is already known about this topic?

The genusAnaplasma contains seven recognized bacterial species, mainly transmitted by tick bites. The two species, A. phagocytophilum and A. capra, are known commonly to cause diseases in humans.

What is added by this report?

Anaplasma bovis was initially thought to be only an animal agent until the first patient case was reported in 2019. This study investigated another two patients who became sick within one month in the same township and were infected with A. bovis in Anhui Province.

What are the implications for public health practice?

This study suggested that more A. bovis-infected patients may exist in this area and that patients with anaplasmosis require an early and specific diagnosis.

Identification of Rickettsia spp. and Babesia conradae in Dermacentor spp. Collected from Dogs and Cats Across the United States

In the United States, Dermacentor variabilis and Dermacentor andersoni are considered key vectors for Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. Through regional surveillance, a wide diversity of Rickettsia spp. have been documented in D. variabilis, and Dermacentor spp. has been suggested as potential vectors for various other pathogens, including Babesia spp. and Ehrlichia canis. To better define the prevalence and diversity of pathogens in Dermacentor spp. across the United States, 848 ticks collected from dogs and cats in 44/50 states in 2018–2019 were tested by PCR for Rickettsia spp.-specific 17 kDa and ompA gene fragments; a subset of Dermacentor spp. was also tested with PCR, targeting fragments of the 18S and large subunit region rRNA genes of Babesia spp. and 16S rRNA genes of E. canis. Rickettsia spp. was identified in 12.5% (106/848) of ticks. Species detected include Rickettsia montanensis (n = 64 ticks), Rickettsia bellii (n = 15 ticks), Rickettsia rhipicephali (n = 13 ticks), Rickettsia peacockii (n = 8 ticks), Rickettsia amblyommatis (n = 3 ticks), Rickettsia cooleyi (n = 1 tick), and unclassified Rickettsia spp. (n = 2 ticks). Ticks with R. montanensis and R. bellii were submitted from every U.S. region; R. rhipicephali was predominantly detected in ticks from the southern half of the United States, and all R. peacockii-positive ticks were D. andersoni that originated from the Rocky Mountain states. Ehrlichia canis was not detected in any Dermacentor spp., and Babesia conradae was detected in two Dermacentor albipictus. Because most ticks had fed on dogs or cats before submission, these findings do not implicate a given Dermacentor sp. as a primary vector of these agents, but in regard to Rickettsia spp., the data do support other published work showing D. variabilis harbors a diversity of Rickettsia species with unknown implications for animal and human health.

Molecular detection of Anaplasma spp., Babesia spp. and Theileria spp. in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibetan Plateau, China

BACKGROUND

Anaplasma, Babesia and Theileria are tick-borne pathogens (TBPs) that affect livestock worldwide. However, information on these pathogens in yaks (Bos grunniens) and Tibetan sheep (Ovis aries) on the Qinghai-Tibet Plateau (QTP), China, is limited. In this study, Anaplasma spp., Babesia spp. and Theileria spp. infections were assessed in yaks and Tibetan sheep from Qinghai Province.

METHODS

A total of 734 blood samples were collected from 425 yaks and 309 Tibetan sheep at nine sampling sites. Standard or nested polymerase chain reaction was employed to screen all the blood samples using species- or genus-specific primers.

RESULTS

The results showed that 14.1% (60/425) of yaks and 79.9% (247/309) of Tibetan sheep were infected with at least one pathogen. Anaplasma ovis, Anaplasma bovis, Anaplasma capra, Anaplasma phagocytophilum, Babesia bovis and Theileria spp. were detected in this study, with total infection rates for all the assessed animals of 22.1% (162/734), 16.3% (120/734), 23.6% (173/734), 8.2% (60/734), 2.7% (20/734) and 19.3% (142/734), respectively. For yaks, the infection rate of A. bovis was 6.4% (27/425), that of B. bovis was 4.7% (20/425) and that of Theileria spp. was 3.3% (14/425). Moreover, 52.4% (162/309) of the Tibetan sheep samples were infected with A. ovis, 30.1% (93/309) with A. bovis, 56.0% (173/309) with A. capra, 19.4% (60/309) with A. phagocytophilum and 41.4% (128/309) with Theileria spp.

CONCLUSIONS

This study revealed the prevalence of Anaplasma spp., Babesia spp. and Theileria spp. in yaks and Tibetan sheep in Qinghai Province, China, and provides new data for a better understanding of the epidemiology of TBPs in these animals in this area of the QTP, China.

Ticks and Tick-Borne Pathogens Abound in the Cattle Population of the Rabat-Sale Kenitra Region, Morocco

Tick-borne pathogens cause the majority of diseases in the cattle population in Morocco. In this study, ticks were collected from cattle in the Rabat-Sale-Kenitra region of Morocco and identified morphologically, while tick-borne pathogens were detected in cattle blood samples via polymerase chain reaction assay and sequencing. A total of 3394 adult ixodid ticks were collected from cattle and identified as eight different tick species representing two genera, Hyalomma and Rhipicephalus. The collected ticks consisted of Hyalomma marginatum, Hyalomma anatolicum excavatum, Rhipicephalus sanguineus sensu lato, Rhipicephalus bursa, Hyalomma detritum, Hyalomma lusitanicum, Hyalomma dromedarii, and Hyalomma impeltatum. The overall prevalence of tick-borne pathogens in blood samples was 63.8%, with 29.3% positive for Babesia/Theileria spp., 51.2% for Anaplasma/Ehrlichia spp., and none of the samples positive for Rickettsia spp. Sequencing results revealed the presence of Theileria annulata, Babesia bovis, Anaplasma marginale, Theileria buffeli, Theileria orientalis, Babesia occultans, Anaplasma phagocytophilum, Anaplasma capra, Anaplasma platys, Anaplasma bovis, Ehrlichia minasensis, and one isolate of an unknown bovine Anaplasma sp. Crossbreeds, females, older age, and high tick infestation were the most important risk factors for the abundance of tick-borne pathogens, which occurred most frequently in Jorf El Melha, Sidi Yahya Zaer, Ait Ichou, and Arbaoua locations.

Epidemiology, Diagnosis, and Control of Canine Infectious Cyclic Thrombocytopenia and Granulocytic Anaplasmosis: Emerging Diseases of Veterinary and Public Health Significance

This review highlights the diagnostic methods used, the control strategies adopted, and the global epidemiological status of canine cyclic thrombocytopenia and granulocytic anaplasmosis at the animal–human interface. Canine anaplasmosis is an important worldwide disease, mainly caused by Anaplasma platys and A. phagocytophilum with zoonotic implications. A. platys chiefly infects platelets in canids, while A. phagocytophilum is the most common zoonotic pathogen infecting neutrophils of various vertebrate hosts. Diagnosis is based on the identification of clinical signs, the recognition of intracellular inclusions observed by microscopic observation of stained blood smear, and/or methods detecting antibodies or nucleic acids, although DNA sequencing is usually required to confirm the pathogenic strain. Serological cross-reactivity is the main problem in serodiagnosis. Prevalence varies from area to area depending on tick exposure. Tetracyclines are significant drugs for human and animal anaplasmosis. No universal vaccine is yet available that protects against diverse geographic strains. The control of canine anaplasmosis therefore relies on the detection of vectors/reservoirs, control of tick vectors, and prevention of iatrogenic/mechanical transmission. The control strategies for human anaplasmosis include reducing high-risk tick contact activities (such as gardening and hiking), careful blood transfusion, by passing immunosuppression, recognizing, and control of reservoirs/vectors.

Keeping the host alive - lessons from obligate intracellular bacterial pathogens

Mammals have evolved sophisticated host cell death signaling pathways as an important immune mechanism to recognize and eliminate cell intruders before they establish their replicative niche. However, intracellular bacterial pathogens that have co-evolved with their host have developed a multitude of tactics to counteract this defense strategy to facilitate their survival and replication. This requires manipulation of pro-death and pro-survival host signaling pathways during infection. Obligate intracellular bacterial pathogens are organisms that absolutely require an eukaryotic host to survive and replicate, and therefore they have developed virulence factors to prevent diverse forms of host cell death and conserve their replicative niche. This review encapsulates our current understanding of these host-pathogen interactions by exploring the most relevant findings of Anaplasma spp., Chlamydia spp., Rickettsia spp. and Coxiella burnetii modulating host cell death pathways. A detailed comprehension of the molecular mechanisms through which these obligate intracellular pathogens manipulate regulated host cell death will not only increase the current understanding of these difficult-to-study pathogens but also provide insights into new tools to study regulated cell death and the development of new therapeutic approaches to control infection.

A Comparative Spatial and Climate Analysis of Human Granulocytic Anaplasmosis and Human Babesiosis in New York State (2013-2018)

Human granulocytic anaplasmosis (HGA) and human babesiosis are tick-borne diseases spread by the blacklegged tick (Ixodes scapularis Say, Acari: Ixodidae) and are the result of infection with Anaplasma phagocytophilum and Babesia microti, respectively. In New York State (NYS), incidence rates of these diseases increased concordantly until around 2013, when rates of HGA began to increase more rapidly than human babesiosis, and the spatial extent of the diseases diverged. Surveillance data of tick-borne pathogens (2007 to 2018) and reported human cases of HGA (n = 4,297) and human babesiosis (n = 2,986) (2013-2018) from the New York State Department of Health (NYSDOH) showed a positive association between the presence/temporal emergence of each pathogen and rates of disease in surrounding areas. Incidence rates of HGA were higher than human babesiosis among White and non-Hispanic/non-Latino individuals, as well as all age and sex groups. Human babesiosis exhibited higher rates among non-White individuals. Climate, weather, and landscape data were used to build a spatially weighted zero-inflated negative binomial (ZINB) model to examine and compare associations between the environment and rates of HGA and human babesiosis. HGA and human babesiosis ZINB models indicated similar associations with forest cover, forest land cover change, and winter minimum temperature; and differing associations with elevation, urban land cover change, and winter precipitation. These results indicate that tick-borne disease ecology varies between pathogens spread by I. scapularis.

Seroprevalence of Antibodies against Tick-Borne Pathogens in Czech Patients with Suspected Post-Treatment Lyme Disease Syndrome

The hypothesized importance of coinfections in the pathogenesis of post-treatment Lyme disease syndrome (PTLDS) leads to the use of combined, ongoing antimicrobial treatment in many cases despite the absence of symptoms typical of the presence of infection with specific pathogens. Serum samples from 103 patients with suspected post-treatment Lyme disease syndrome were tested for the presence of antibodies to the major tick-borne pathogens Anaplasma phagocytophilum, Bartonella henselae/Bartonella quinatana, and Babesia microti. Although the presence of anti-Anaplasma antibodies was detected in 12.6% of the samples and anti-Bartonella antibodies in 9.7% of the samples, the presence of antibodies against both pathogens in the same samples or anti-Babesia antibodies in the selected group of patients could not be confirmed. However, we were able to detect autoantibodies, mostly antinuclear, in 11.6% of the patients studied. Our results are in good agreement with previously published studies showing the presence of a wide spectrum of autoantibodies in some patients with complicated forms of Lyme disease and post-treatment Lyme disease syndrome, but they do not reveal a significant influence of co-infections on the development of PTLDS in the studied group of patients.

Ehrlichiosis and Anaplasmosis among Transfusion and Transplant Recipients in the United States

Physicians should be aware that these infections are rare but can have severe outcomes.

Ehrlichiosis and anaplasmosis are emerging tickborne diseases that can also be transmitted through blood transfusions or organ transplants. Since 2000, ehrlichiosis and anaplasmosis cases in the United States have increased substantially, resulting in potential risk to transplant and transfusion recipients. We reviewed ehrlichiosis and anaplasmosis cases among blood transfusion and solid organ transplant recipients in the United States from peer-reviewed literature and Centers for Disease Control and Prevention investigations. We identified 132 cases during 1997–2020, 12 transfusion-associated cases and 120 cases in transplant recipients; 8 cases were donor-derived, and in 13 cases illness occurred <1 year after transplant. Disease in the remaining 99 cases occurred ≥1 year after transplant, suggesting donor-derived disease was unlikely. Severe illness or death were reported among 15 transfusion and transplant recipients. Clinicians should be alert for these possible infections among transfusion and transplant recipients to prevent severe complications or death by quickly treating them.

Detection of Anaplasma phagocytophilum in Wild and Farmed Cervids in Poland

Background: The role of cervids in the circulation of A. phagocytophilum has not yet been clearly determined; however, several species of wild and farm cervids may be a natural reservoir of this bacteria. Methods: Spleen and liver tissue samples were taken from 207 wild (red deer, roe deer, fallow deer and moose) and farmed cervids (red deer and fallow deer) from five geographical areas. These were tested for the A. phagocytophilum16S rDNA partial gene by nested PCR. Results: Anaplasma spp. were detected in 91 of 207 examined cervids (prevalence 43.9%). Three different variants of 16S rDNA partial gene were reported, one for the first time. Anaplasma phagocytophilum was more often detected in young specimens than in adults and more often in the spleen than in the liver. Conclusions: Cervids from the four sites across Poland were found to be major natural reservoirs of various strains of A. phagocytophilum. This is the first study to use spleen and liver as biological material to detect A. phagocytophilum in moose in Poland.