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

Genomic characters of Anaplasma bovis and genetic diversity in China

The emergence of Anaplasma bovis or A. bovis-like infection in humans from China and the United States of America has raised concern about the public health importance of this pathogen. Although A. bovis has been detected in a wide range of ticks and mammals in the world, no genome of the pathogen is available up to now, which has prohibited us from better understanding the genetic basis for its pathogenicity. Here we describe an A. bovis genome from metagenomic sequencing of an infected goat in China. Anaplasma bovis had the smallest genome of the genus Anaplasma, and relatively lower GC content. Phylogenetic analysis of single-copy orthologue sequence showed that A. bovis was closely related to A. platys and A. phagocytophilum, but relatively far from intraerythrocytic Anaplasma species. Anaplasma bovis had 116 unique orthogroups and lacked 51 orthogroups in comparison to other Anaplasma species. The virulence factors of A. bovis were significantly less than those of A. phagocytophilum, suggesting less pathogenicity of A. bovis. When tested by specific PCR assays, A. bovis was detected in 23 of 29 goats, with an infection rate up to 79.3% (95% CI: 64.6% ∼94.1%). The phylogenetic analyses based on partial 16S rRNA, gltA and groEL genes indicated that A. bovis had high genetic diversity. The findings of this study lay a foundation for further understanding of the biological characteristics and genetic diversity of A. bovis, and will facilitate the formulation of prevention and control strategies.

First molecular survey of tick-borne protozoan and bacterial pathogens in the questing tick population in Bangladesh

Questing ticks carry various tick-borne pathogens (TBPs) that are responsible for causing tick-borne diseases (TBDs) in humans and animals around the globe, especially in the tropics and sub-tropics. Information on the distribution of ticks and TBPs in a specific geography is crucial for the formulation of mitigation measures against TBDs. Therefore, this study aimed to survey the TBPs in the questing tick population in Bangladesh. A total of 2748 questing hard ticks were collected from the pastures in Sylhet, Bandarban, Sirajganj, Dhaka, and Mymensingh districts through the flagging method. After morphological identification, the ticks were grouped into 142 pools based on their species, sexes, life stages, and collection sites. The genomic DNA extracted from tick specimens was screened for 14 pathogens, namely Babesia bigemina (AMA-1), Babesia bovis (RAP-1), Babesia naoakii (AMA-1), Babesia ovis (18S rRNA), Theileria luwenshuni (18S rRNA), Theileria annulata (Tams-1), Theileria orientalis (MPSP), Anaplasma marginale (groEL), Anaplasma phagocytophilum (16S rRNA), Anaplasma bovis (16S rRNA), Anaplasma platys (16S rRNA), Ehrlichia spp. (16S rRNA), Rickettsia spp. (gltA), and Borrelia (Bo.) spp. (flagellin B) using genus and species-specific polymerase chain reaction (PCR) assays. The prevalence of the detected pathogens was calculated using the maximum likelihood method (MLE) with 95 % confidence interval (CI). Among 2748 ixodid ticks, 2332 (84.86 %) and 416 (15.14 %) were identified as Haemaphysalis bispinosa and Rhipicephalus microplus, respectively. Haemaphysalis bispinosa was found to carry all the seven detected pathogens, while larvae of R. microplus were found to carry only Bo. theileri. Among the TBPs, the highest detection rate was observed in A. bovis (20/142 pools, 0.81 %, CI: 0.51-1.20), followed by T. orientalis (19/142 pools, 0.72 %, CI: 0.44-1.09), T. luwenshuni (9/142 pools, 0.34 %, CI: 0.16-0.62), B. ovis (4/142 pools, 0.15 %, CI: 0.05 - 0.34) and Bo. theileri (4/142 pools, 0.15 %, CI: 0.05-0.34), Ehrlichia ewingii (3/142 pools, 0.11 %, CI: 0.03-0.29), and Babesia bigemina (1/142, 0.04 %, CI: 0.00 - 0.16). This study reports the existence of T. luwenshuni, E. ewingii, and Bo. theileri in Bangladesh for the first time. The novel findings of this study are the foremost documentation of transovarian transmission of B. bigemina and E. ewingii in H. bispinosa and also provide primary molecular evidence on the presence of E. ewingii and Bo. theileri in H. bispinosa. Therefore, this study may shed light on the circulating TBPs in ticks in the natural environment and thereby advocate awareness among physicians and veterinarians to control and prevent TBDs in Bangladesh.

Detection of Anaplasma and Ehrlichia bacteria in humans, wildlife, and ticks in the Amazon rainforest

Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for Ehrlichia and Anaplasma infections in the rainforests of the Amazon biome of French Guiana. Through molecular genetics and metagenomics reconstruction, we observe a high indigenous biodiversity of infections circulating among humans, wildlife, and ticks inhabiting these ecosystems. Molecular typing identifies these infections as highly endemic, with a majority of new strains and putative species specific to French Guiana. They are detected in unusual rainforest wild animals, suggesting they have distinctive sylvatic transmission cycles. They also present potential health hazards, as revealed by the detection of Candidatus Anaplasma sparouinense in human red blood cells and that of a new close relative of the human pathogen Ehrlichia ewingii, Candidatus Ehrlichia cajennense, in the tick species that most frequently bite humans in South America. The genome assembly of three new putative species obtained from human, sloth, and tick metagenomes further reveals the presence of major homologs of Ehrlichia and Anaplasma virulence factors. These observations converge to classify health hazards associated with Ehrlichia and Anaplasma infections in the Amazon biome as distinct from those in the Northern Hemisphere.

Molecular Characterization of Tick-borne Pathogens in Bactrian Camels and Ticks from Gansu Province, China

PURPOSE

Ticks are dangerous ectoparasites for humans and other animals, and tick-borne pathogens of Bactrian camels have been epidemiologically surveyed in Gansu Province, China. We aimed to determine the current distribution of tick-borne pathogens among Bactrian camels in Gansu during August 2013 using molecular tools.

METHODS

All ticks underwent morphological identification. We extracted DNA from the blood samples and ticks, screened them for Theileria, Babesia, Anaplasma, and Ehrlichia using standard or nested PCR with specific primers.

RESULTS

All ticks collected from the skin were identified as Hyalomma asiaticum. The blood and tick samples harbored similar pathogens, including the Theileria species, T. annulata, T. luwenshuni, T. uilenbergi, and T. capreoli, the Anaplasma species A. bovis and uncultured Anaplasma, the Ehrlichia species E. canis and uncultured Ehrlichia, and a new haplotype of Babesia species.

CONCLUSION

Our findings of anaplasmataceae and piroplasmida in Bactrian camels in Gansu provide a theoretical basis for deeper investigation into the epidemiology of tick-borne pathogens in these camels.

First report on the molecular detection and genetic diversity of Anaplasma marginale in healthy dairy cattle in Khon Kaen province, Thailand

Background and Aim

Bovine anaplasmosis (BA) is one of the most important diseases of ruminants worldwide, causing significant economic losses in the livestock industry due to the high morbidity and mortality in susceptible cattle herds. Anaplasma marginale is the main causative agent of BA occurring worldwide in tropical and subtropical regions. This study aimed to investigate the first molecular detection and genetic diversity of A. marginale in dairy cattle in Khon Kaen Province, Thailand.

Materials and Methods

Blood samples were collected from 385 lactating cows from 40 dairy farms in five districts of Khon Kaen, regardless of age and health status. To detect A. marginale, all DNA preparations were used for molecular diagnosis using a single polymerase chain reaction with the msp4 gene target. A phylogenetic tree was constructed from the msp4 gene sequences using molecular genetic characterization. Genetic diversity was calculated as haplotype diversity, haplotype number, number of nucleotide differences, nucleotide diversity, and average number of nucleotide differences.

Results

The overall prevalence of A. marginale was 12.72% (49/385). The highest prevalence (17.19%) was found in Ubolratana district, followed by Muang, Kranuan, Khao Suan Kwang, and Nam Phong districts (14.94%, 14.74%, 13.79%, and 3.70%, respectively). Phylogenetic analysis showed that A. marginale was closely related to isolates from Australia (98.96%), China (99.68%), Spain (99.74%), and the USA (99.63%).

Conclusion

The molecular prevalence of BA in dairy cattle is the first to be observed in this area, and the genetic variability with separated clusters shown in the msp4 gene of A. marginale revealed species variation in dairy cattle. This significant genetic diversity contributes to the understanding of the diversity of A. marginale and will be important for the control and prevention of A. marginale in dairy cattle.

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.

Anaplasma bovis-Like Infections in Humans, United States, 2015-2017

We detected the DNA of an Anaplasma bovis-like bacterium in blood specimens from 4 patients from the United States with suspected tickborne illnesses. Initial molecular characterization of this novel agent reveals identity to A. bovis-like bacteria detected in Dermacentor variabilis ticks collected from multiple US states.

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.

Anaplasma Species in Ticks Infesting Mammals of Sardinia, Italy

Ticks are hematophagous ectoparasites that are recognized for their ability to vector a wide variety of pathogens of viral, bacterial, protozoal, and helminthic nature to vertebrate hosts. Among the different diseases transmitted by ticks, also called "Tick-Borne Diseases" (TBD), many are zoonotic. Pathogens of the genus Anaplasma refer to obligate intracellular bacteria within the Rickettsiales order transmitted mainly through tick bites and considered as well-established threats to domestic animals, livestock, and humans, worldwide. In this retrospective study, 156 ticks collected from twenty goats, one marten, and one cattle from several Sardinian sites, were examined by molecular analyses to detect the presence of Anaplasma species. A total of 10 (10/156; 6.4%) ticks were shown to be Anaplasma-positive by PCR screening. After sequence analyses, A. phagocytophilum was detected in four Rhipicephalus sanguineus s.l. (3.3%) and four Rh. bursa (11%) ticks from goats, while one Rh. sanguineus s.l. (0.8%) and one Rh. bursa (2.8%) collected from the marten and cattle, respectively, exhibited 100% of identity with A. marginale strains. In this study, we provide the first description and molecular detection of A. marginale and A. phagocytophilum in ticks of the Rhiphicephalus genus in Sardinia. Considering the growing impact of tick-borne Anaplasma pathogens on human health, further studies are necessary to monitor the prevalence of these pathogens in Sardinia.

Detection and Genotypic Analysis of Anaplasma bovis and A. phagocytophilum in Horse Blood and Lung Tissue

A clinical case of Anaplasma bovis was reported for the first time in our previous study (2019) in a horse, a nondefinitive host. Although A. bovis is a ruminant and not a zoonotic pathogen, it is responsible for persistent infections in horses. In this follow-up study, the prevalence of Anaplasma spp., including A. bovis, was assessed in horse blood and lung tissue samples to fully understand Anaplasma spp. pathogen distribution and the potential risk factors of infection. Among 1696 samples, including 1433 blood samples from farms nationwide and 263 lung tissue samples from horse abattoirs on Jeju Island, a total of 29 samples (1.7%) tested positive for A. bovis and 31 (1.8%) samples tested positive for A. phagocytophilum, as determined by 16S rRNA nucleotide sequencing and restriction fragment length polymorphism. This study is the first to detect A. bovis infection in horse lung tissue samples. Further studies are needed to clarify the comparison of sample types within cohorts. Although the clinical significance of Anaplasma infection was not evaluated in this study, our results emphasize the need to clarify the host tropism and genetic divergence of Anaplasma to enable the development of effective prevention and control measures through broad epidemiological studies.

Emergence of Anaplasma Species Related to A. phagocytophilum and A. platys in Senegal

The genus Anaplasma (Anaplasmataceae, Rickettsiales) includes tick-transmitted bacterial species of importance to both veterinary and human medicine. Apart from the traditionally recognized six Anaplasma species (A. phagocytophilum, A. platys, A. bovis, A. ovis, A. centrale, A. marginale), novel strains and candidate species, also of relevance to veterinary and human medicine, are emerging worldwide. Although species related to the zoonotic A. platys and A. phagocytophilum have been reported in several African and European Mediterranean countries, data on the presence of these species in sub-Saharan countries are still lacking. This manuscript reports the investigation of Anaplasma strains related to zoonotic species in ruminants in Senegal by combining different molecular tests and phylogenetic approaches. The results demonstrated a recent introduction of Candidatus (Ca) Anaplasma turritanum, a species related to the pathogenic A. platys, possibly originating by founder effect. Further, novel undetected strains related to Candidatus (Ca) Anaplasma cinensis were detected in cattle. Based on groEL and gltA molecular comparisons, we propose including these latter strains into the Candidatus (Ca) Anaplasma africanum species. Finally, we also report the emergence of Candidatus (Ca) A. boleense in Senegal. Collectively, results confirm that Anaplasma species diversity is greater than expected and should be further investigated, and that Anaplasma routine diagnostic procedures and epidemiological surveillance should take into account specificity issues raised by the presence of these novel strains, suggesting the use of a One Health approach for the management of Anaplasmataceae in sub-Saharan Africa.