First molecular survey of Anaplasma bovis in small ruminants from Tunisia

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.

Current status of ruminant anaplasmosis in Algeria: a systematic review and meta-analysis

Anaplasmosis is an emerging infectious disease that is being recognised all over the world, with impact on animal health.This systematic review and meta-analysis aimed to assess the rate infection of Anaplasma spp. infection in Algerian ruminants. Three databases were searched to identify eligible studies for the final systematic review and meta-analysis. The 'meta' package in the R software was used for the meta-analysis, and the random effects model was chosen to pool the data. Meta-analysis encompasses 14 research papers spanning 19 years (2004-2023), out of an initial pool of 737 articles retrieved from various databases. The study included a total of 1515 cattle, 190 sheep, and 310 goats, and the overall Anaplasma infection rate was estimated at 28% (95% CI, 17-41%). The analysis revealed varying infection rates among species, with cattle at 20%, sheep at 30%, and goats at 61%. Five classified species and two unclassified strains belonging to Anaplasma genus were identified in ruminants, which are A. marginale, A. centrale, A. bovis, A. ovis, A. phagocytophilum, A. phagocytophilum-like strains, and A. platys-like strains. Among these, A. marginale was prevalent in ten out of eleven cattle studies. The data also revealed regional variations, with Northeastern Algeria showing a higher infection rate (26%) compared to North-central Algeria (9%). In the subgroup analysis, clinically healthy cattle had a higher infection rate (28%) compared to suspected disease cattle (16%). Molecular biology screening methods yielded a significantly higher infection rate (33%) than microscopy (12%). Gender analysis suggested slightly higher infection rates among male cattle (19%) compared to females (16%). Age analysis indicated that Anaplasma infection was more common in cattle less than 12 months (14%) compared to those over 12 months (9%). This systematic review provides valuable insights, highlighting the need for continued surveillance and potential preventive strategies in different regions and among different animal populations in Algeria.

Molecular detection and associated risk factors of Anaplasma marginale, A. ovis and A. platys in sheep from Algeria with evidence of the absence of A. phagocytophilum

Anaplasma species are obligate intracellular rickettsial pathogens that cause significant diseases in animals and humans. Despite their importance, limited information on Anaplasma infections in Algeria has been published thus far. This study aimed to assess the infection rate, characterize Anaplasma species, and identify associated risk factors in selected sheep farms across Oum El Bouaghi region in Algeria. In 2018, we collected 417 blood samples from sheep (Ovis aries) and performed molecular characterization of Anaplasma species infecting these animals. This characterization involved the use of 16S rRNA, msp2, rpoB, and msp5 genes, which were analyzed through nested PCR, qPCR, cPCR, DNA sequencing, and subsequent phylogenetic analysis. Our findings revealed infection rates of 12.7 % for Anaplasma species detected, with Anaplasma ovis at 10.8 %, Anaplasma marginale at 1.7 %, and Anaplasma platys at 0.2 %. Interestingly, all tested animals were found negative for Anaplasma phagocytophilum. Statistical analyses, including the Chi-square test and Fisher exact test, failed to establish any significant relationships (p > 0.05) between A. ovis and A. platys infections and variables such as age, sex, sampling season, and tick infestation level. However, A. marginale infection exhibited a significant association with age (p < 0.05), with a higher incidence observed in lambs (5.2 %) compared to other age groups. Remarkably, this study represents the first molecular detection of A. platys and A. marginale in Algerian sheep. These findings suggest that Algerian sheep may serve as potential reservoirs for these pathogens. This research contributes valuable insights into the prevalence and characteristics of Anaplasma infections in Algerian sheep populations, emphasizing the need for further investigation and enhanced surveillance to better understand and manage these diseases.

Molecular surveillance and genetic diversity of Anaplasma spp. in cattle (Bos taurus) and goat (Capra aegagrus hircus) from Hainan island/province, China

Anaplasmosis is a highly prevalent tick-borne intracellular bacterial disease that affects various host species globally, particularly ruminants in tropical and subtropical regions. However, information regarding the distribution and epidemiology of anaplasmosis in small and large ruminants on Hainan Isalnd is limited. To address this knowledge gap, the present study aimed to assess the occurrence of Anaplasma spp. infections in goats (N = 731) and cattle (N = 176) blood samples using nested PCR and conventional PCR based assays. The results revealed an overall prevalence of 30.1% in goats and 14.8% in cattle. The infection rates of A. bovis, A. phagocytophilum, A. ovis and A. capra in goat samples were 22.7%, 13.8%, 2.0% and 3.4%, respectively, while the infection rates of A. bovis, A. phagocytophilum and A. marginale in cattle samples were 11.4%, 6.3% and 5.7%, respectively. A. bovis exhibited the highest prevalence among the Anaplasma spp. in both goat and cattle samples. In addition, the most frequent co-infection was the one with A. phagocytophilum and A. bovis. It was found that the age, sex and feeding habits of cattle and goats were considered to be important risk factors. Evaluation of the risk factor relating to the rearing system showed that the infection rate for the free-range goats and cattle was significantly higher when compared with stall-feeding system.This study represents one of the largest investigations on the distribution, prevalence, and risk factors associated with Anaplasma infection in ruminants on Hainan Island, highlighting a higher circulation of the infection in the region than previously anticipated. Further reasesrch is necessary to investigate tick vectors, reservoir animals, and the zoonotic potential of the Anaplasma spp. in this endemic region of Hainan Island.

Anaplasma Species in Africa-A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

Anaplasma ovis Prevalence Assessment and Cross Validation Using Multiparametric Screening Approach in Sheep from Central Tunisia

We conducted a 5-month-long screening of Anaplasma spp. and Anaplasma ovis infection in sheep from central Tunisia. During this longitudinal study, we investigated the infection dynamics using both direct and indirect assessments validated with a polymerase chain reaction (PCR) as the gold standard method. The experimental design included 84 male lambs aged from 6 to 8 months, and 32 ewes, both chosen randomly from June to November with a periodicity of 2 weeks approximately between June and September, and 1 month between September and November. A total of 9 field visits were carried out in this period during which animals were clinically examined and biological samples were extracted. Thus, a total of 716 blood smears, 698 sera from the nine sampling dates, as well as 220 blood samples from the first and the ninth sampling dates were collected from apparently healthy lambs and ewes, respectively, and analyzed by competitive enzyme-linked immunosorbent assay (cELISA) and polymerase chain reaction (PCR) assay, for the detection of Anaplasma antibodies and A. ovis DNA, respectively. Sera were analyzed by competitive enzyme-linked immunosorbent assay (cELISA) and PCR, for the detection of Anaplasma antibodies and A. ovis DNA, respectively. The Anaplasma spp. initial seroprevalence rate was 33.3% in lambs and 100% in ewes, and it then flowed in an upward trend to reach a maximum of 52.6% in lambs, whereas in ewes, the Anaplasma spp. seroprevalence rate remained unchanged and equal to 100%. Meanwhile, the A. ovis initial molecular prevalence was 22.6% at the first visit and 26.3% at the last visit in lambs, whereas in ewes, the molecular prevalence rates of A. ovis were higher in both the first and the last visit estimated at 100% and 85.7%, respectively. The Kappa coefficient between cELISA and PCR indicated a moderate level of agreement on the first sampling date (0.67) and a low agreement level on the last (0.43). Furthermore, an exploratory data analysis using a multimodal machine learning approach highlighted the underlying pattern of each analytical technique used in this study. In this prospect, we were able to establish the performance of each technique at detecting Anaplasma spp. in sheep. The combination of these approaches should improve the field assessment while promoting a data-based decision in precision epidemiology. The genetic follow-up test relevant to A. ovis msp4 sequences revealed three different genotypes, two of which were previously described in Italy.

Molecular survey for tick-borne pathogens and associated risk factors in sheep and goats in Kano Metropolis, Nigeria

Tick-borne pathogens (TBPs) pose an increased health and productivity risk to livestock in sub-Saharan Africa. Information regarding TBPs infecting small ruminants in Kano metropolis is scarce. Therefore, we investigated the molecular epidemiology of tick-borne pathogens of economic importance from sheep and goats in Kano, Nigeria using Polymerase chain reaction (PCR). A total of 346 blood DNA samples were collected from small ruminants and analyzed for TBPs using PCR and sequencing. Risk of infection was determined for age, sex, breed and animal species. Our results indicate the absence of piroplasmids (Babesia/Theileria) and Rickettsia spp. infections. The overall prevalence for Anaplasma spp. was 9.25% (32/346) with a higher prevalence in goats 13.59% (25/184) compared with sheep 4.32% (7/162). With respect to age of animals, goats >4 years had the highest prevalence of 32.45% (11/37) which differs significantly (P = 0.0059) compared with other age categories. Cross breed goats had a prevalence of 15.63% (5/32) compared with Kano brown breed 14.08 (20/142). Sex significant difference (P = 0.029) was observed in the goats with females having the highest prevalence 20.89% (14/67) compared with males 9.40% (11/117). Furthermore, with regards to sheep, no significant difference (P > 0.05) was observed with respect to age and breed. Finally, no significant difference (P > 0.05) was observed with the prevalence of Anaplasma spp. due to Body condition score (BCS) in both sheep and goats. Conclusively, the occurrence of TBPs in small ruminants is low. Continuous efforts in tick control must be sustained to ensure high productive yield and reduced disease burden associated with TBPs of sheep and goats in Kano metropolis.

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.

First Molecular Evidence for the Presence of Anaplasma phagocytophilum in Naturally Infected Small Ruminants in Tunisia, and Confirmation of Anaplasma ovis Endemicity

Anaplasma species are obligate intracellular rickettsial vector-borne pathogens that impose economic constraints on animal breeders and threaten human health. Anaplasma ovis and Anaplasma phagocytophilum infect sheep and goats worldwide. A duplex PCR targeting the msp2 and msp4 genes of A. phagocytophilum and A. ovis, respectively, was developed to analyze the field blood samples collected from sheep and goats. A total of 263 apparently healthy small ruminants from 16 randomly selected flocks situated in 3 bioclimatic zones in Tunisia were analyzed for Anaplasma infections. Anaplasma spp. was detected in 78.3% (95% confidence interval (CI): 72.8–83.1) of the analyzed animals. The prevalence of A. ovis in sheep (80.4%) and goats (70.3%) was higher than that of A. phagocytophilum (7.0% in sheep and 1.6% in goats). Using an inexpensive, specific, and rapid duplex PCR assay, we provide, to the best of our knowledge, the first molecular evidence for the presence of A. phagocytophilum in small ruminants in Tunisia. A. phagocytophilum generally presented as a co-infection with A. ovis. This study provides important data to understand the epidemiology of anaplasmosis in small ruminants, and highlights the risk of contracting the infection upon tick exposure.

Genome variation in tick infestation and cryptic divergence in Tunisian indigenous sheep

Background

Ticks are obligate haematophagous ectoparasites considered second to mosquitos as vectors and reservoirs of multiple pathogens of global concern. Individual variation in tick infestation has been reported in indigenous sheep, but its genetic control remains unknown.

Results

Here, we report 397 genome-wide signatures of selection overlapping 991 genes from the analysis, using ROH, LR-GWAS, XP-EHH, and F_ST, of 600 K SNP genotype data from 165 Tunisian sheep showing high and low levels of tick infestations and piroplasm infections. We consider 45 signatures that are detected by consensus results of at least two methods as high-confidence selection regions. These spanned 104 genes which included immune system function genes, solute carriers and chemokine receptor. One region spanned STX5, that has been associated with tick resistance in cattle, implicating it as a prime candidate in sheep. We also observed RAB6B and TF in a high confidence candidate region that has been associated with growth traits suggesting natural selection is enhancing growth and developmental stability under tick challenge. The analysis also revealed fine-scale genome structure indicative of cryptic divergence in Tunisian sheep.

Conclusions

Our findings provide a genomic reference that can enhance the understanding of the genetic architecture of tick resistance and cryptic divergence in indigenous African sheep.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08321-1.

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.

Screening and Analysis of Anaplasma marginale Tunisian Isolates Reveal the Diversity of lipA Phylogeographic Marker and the Conservation of OmpA Protein Vaccine Candidate

Bovine anaplasmosis caused by Anaplasma marginale is a disease responsible for serious animal health problems and great economic losses all over the world. Thereby, the identification of A. marginale isolates from various bioclimatic areas in each country, the phylogeographic analysis of these isolates based on the most informative markers, and the evaluation of the most promising candidate antigens are crucial steps in developing effective vaccines against a wide range of A. marginale strains. In order to contribute to this challenge, a total of 791 bovine samples from various bioclimatic areas of Tunisia were tested for the occurrence of A. marginale DNA through msp4 gene fragment amplification. Phylogeographic analysis was performed by using lipA and sucB gene analyses, and the genetic relationship with previously characterized A. marginale isolates and strains was analyzed by applying similarity comparison and phylogenetic analysis. To evaluate the conservation of OmpA protein vaccine candidate, almost complete ompA nucleotide sequences were also obtained from Tunisian isolates, and various bioinformatics software were used in order to analyze the physicochemical properties and the secondary and tertiary structures of their deduced proteins and to predict their immunodominant epitopes of B and T cells. A. marginale DNA was detected in 19 bovine samples (2.4%). Risk factor analysis shows that cattle derived from subhumid bioclimatic area were more infected than those that originated from other areas. The analysis of lipA phylogeographic marker indicated a higher diversity of Tunisian A. marginale isolates compared with other available worldwide isolates and strains. Molecular, phylogenetic, and immuno-informatics analyses of the vaccine candidate OmpA protein demonstrated that this antigen and its predicted immunodominant epitopes of B and T cells appear to be highly conserved between Tunisian isolates and compared with isolates from other countries, suggesting that the minimal intraspecific modifications will not affect the potential cross-protective capacity of humoral and cell-mediated immune responses against multiple A. marginale worldwide strains.

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.

Molecular identification and genetic characterization of tick-borne pathogens in sheep and goats at two farms in the central and southern regions of Malawi

Tick-borne diseases (TBDs) caused by pathogens belonging to the genera Anaplasma, Ehrlichia, Babesia and Theileria in small ruminants are widespread in the tropical and sub-tropical countries. The epidemiology of tick-borne pathogens (TBPs) in small ruminants is less understood compared to those infecting cattle in general. This study was carried out to investigate and characterize TBPs in sheep and goats using molecular tools. A total of 107 blood samples from sheep (n = 8) and goats (n = 99) were collected from animals that were apparently healthy from two farms in the central and the southern regions of Malawi. The V4 hypervariable region of the 18S ribosomal RNA gene (rDNA) and the V1 hypervariable region of the 16S rDNA polymerase chain reaction (PCR) assays were used for detection of tick-borne piroplasms and Anaplasmataceae, respectively. Almost the full-length 18S rDNA and the heat shock protein (groEL) gene sequences were used for genetic characterization of the piroplasms and Anaplasmataceae, respectively. The results showed that 76.6 % of the examined animals (n = 107) were positive for at least one TBP. The overall co-infection with at least two TBPs was observed in forty-eight animals (45 %). The detected TBPs were Anaplasma ovis (65 %), Ehrlichia ruminantium (4%), Ehrlichia canis (2%), Babesia strain closely related to Babesia gibsoni (1%), Theileria ovis (52 %), Theileria mutans (3%), Theileria separata (2%), Anaplasma sp. (1%) and Theileria sp. strain MSD-like (17 %). To the authors knowledge this is the first molecular study of TBPs in sheep and goats in Malawi. These results have therefore provided a significant milestone in the knowledge of occurrence of TBPs in sheep and goats in Malawi, which is prerequisite to proper diagnosis and control.

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.

Improving specific detection and updating phylogenetic data related to Anaplasma platys-like strains infecting camels (Camelus dromedarius) and their ticks

In camels and their infesting ectoparasites, specific detection of pathogenic Anaplasma platys and genetically related strains (A. platys-like strains) remains problematic. This requires sequencing of the hemi-nested PCR products specific to A. platys and related strains. In this study, a PCR/RFLP method, earlier developed for specific detection of A. platys-like strains in animal species other than camels, was adapted in order to subtype A. platys-like strains isolated from camels and their ticks and to differentiate them from pathogenic A. platys without going through a sequencing step. This approach was used for investigating the infections with A. platys and related strains in 412 Camelus dromedarius camels and 334 feeding ticks from five Tunisian governorates. Microscopic examination using Giemsa-stained blood smears was performed in order to specify which types of cells were infected. Ticks were identified as Hyalomma dromedarii (n = 164, 49%), H. impeltatum (n = 161, 48.3%) and H. excavatum (n = 9, 2.7%). A. platys was not detected in any of the tested camels or ticks. The overall prevalence of A. platys-like strains was 5.6% (23/412) in camels and microscopic examination of infected cells showed a tropism for neutrophil granulocytes. One tick identified as H. dromedarii out of 327 analyzed ticks was found to be infected with A. platys-like strains (0.3%). Alignment, identity comparison and phylogenetic analysis of the 16S rRNA partial sequences obtained in this study suggest that Tunisian dromedaries and feeding ticks are infected with different Anaplasma strains genetically related to A. platys. Sequence analysis and phylogenetic study based on the groEL gene confirm the RFLP results and show that camel strains formed a separate sub-cluster relatively close to A. platys-like strains infecting Tunisian cattle. This adapted RFLP assay allows fast and specific detection of pathogenic A. platys and A. platys-like strains in camels and infesting ticks and has the intrinsic potential of revealing co-infections with these two types of bacteria in the same sample, reducing the time and costs associated with cloning and sequencing during molecular diagnosis.

Molecular investigation of tick-borne infections in cattle from Xinjiang Uygur Autonomous Region, China

Tick-borne diseases cause significant losses to livestock production in tropical and subtropical regions. However, information about the tick-borne infections in cattle in Xinjiang Uygur Autonomous Region (XUAR), northwestern China, is scarce. In this study, nested polymerase chain reaction (PCR) assays and gene sequencing were used to detect and analyze epidemiological features of Babesia bovis, B. bigemina, Coxiella burnetii and Anaplasma bovis infections in XUAR. Out of 195 samples tested, 24 (12.3%), 67 (34.4%), 40 (20.5%) and 10 (5.1%) were positive for B. bovis, B. bigemina, C. burnetii and A. bovis, respectively. Sequencing analysis indicated that B. bovis SBP-4, B. bigemina Rap1a, C. burnetii htpB and A. bovis 16S rRNA genes from XUAR showed 99%-100% identity with documented isolates from other countries. Phylogenetic analyses revealed that B. bovis SBP-4, B. bigemina Rap1a, C. burnetii htpB and A. bovis 16S rRNA gene sequences clustered in the same clade with isolates from other countries. To the best of our knowledge, this is the first report of C. burnetii infection of cattle in XUAR. Furthermore, this study provides important data for understanding the distribution of tick-borne pathogens, and is expected to improve the approach for prevention and control of tick-borne diseases in China.

Molecular detection, genotyping and phylogeny of Anaplasma spp. in Rhipicephalus ticks from Tunisia

In Tunisia, most of Anaplasma species and unclassified strains have been detected in several animals, but data on the occurrence of Anaplasma spp. in ticks are still lacking. In this study, we report the molecular evidence, genetic characterization and phylogeny of Anaplasma spp. in ticks collected from small ruminants. A total of 395 ticks (178 males and 179 females) were collected from sheep (n = 215) and goats (n = 180). Tick species were identified as 232 Rhipicephalus turanicus, 99 Rhipicephalus sanguineus sensu lato, 34 Rhipicephalus bursa and 30 Rhipicephalus annulatus. Overall infection rate of Anaplasma spp. was 5.6% (20/357 analyzed ticks). All positive ticks were collected from goats and found to be infected by A. ovis. R. turanicus is the most infected tick species by A. ovis (7.9%) followed by R. sanguineus s.l. (2.5%) with an absence of infection in R. bursa and R. annulatus. A. ovis prevalence rate varied significantly according to bioclimatic areas and geographic regions. GroEL typing and phylogenetic analysis revealed that these analyzed ticks are infected with various and novel strains of A. ovis. The use of PCR-RFLP method complemented with sequencing and phylogenetic analysis based on 16S rRNA gene confirm that one R. turanicus tick, positive to A. ovis, is co-infected with A. phagocytophilum-like 2 (0.3%). Specific A. phagocytophilum, A. phagocytophilum-like 1, A. marginale, A. centrale, A. bovis, and A. platys and related strains were not detected in any of the tested ticks. Present data expand knowledge about tick-borne bacteria present in ticks and further clarify the transmission cycles of these bacteria and their different elements in Tunisia.

Molecular detection of Anaplasma infections in ixodid ticks from the Qinghai-Tibet Plateau

Anaplasma species are tick-transmitted obligate intracellular bacteria that infect many wild and domestic animals and humans. The prevalence of Anaplasma spp. in ixodid ticks of Qinghai Province is poorly understood. In this study, a total of 1104 questing adult ticks were investigated for the infection of Anaplasma species. As a result, we demonstrated the total infection rates of 3.1, 11.1, 5.6, and 4.5% for A. phagocytophilum, A. bovis, A. ovis and A. capra, respectively. All of the tick samples were negative for A. marginale. The positive rates of A. phagocytophilum, A. ovis and A. capra in different tick species were significantly different. The positive rates of A. capra and A. bovis in the male ticks were significantly higher than that in the female ticks. Sequence analysis of A. ovis showed 99.5-100% identity to the previous reported isolates. The sequences of A. phagocytophilum had 100% identity to strains Ap-SHX21, JC3-3 and ZAM dog-181 from sheep, Mongolian gazelles, and dogs. Two genotypes of A. capra were found based on 16S rRNA, citrate synthase (gltA) gene and heat shock protein (groEL) gene analysis. In conclusion, A. bovis, A. ovis, A. phagocytophilum, and A. capra were present in the ticks in Qinghai Province. Anaplasma infection is associated with tick species, gender and distribution. These data will be helpful for understanding prevalence status of Anaplasma infections in ticks in Qinghai-Tibet Plateau.

First molecular detection of Anaplasma phagocytophilum in the hard tick Rhipicephalus haemaphysaloides in Taiwan

Anaplasma phagocytophilum is transmitted mainly by hard ticks and can cause potentially fatal granulocytic anaplasmosis in humans, but its occurrence in ticks in Taiwan has never been investigated although this pathogen has been detected in Taiwanese rodents before. Ticks collected from small mammals in Hualien, eastern Taiwan, were assayed for Anaplasma infections; infections of Rickettsia and Apicomplexa protozoans were also studied. Of the 270 individually assayed Rhipicephalus haemaphysaloides ticks, A. phagocytophilum was identified in a nymphal tick. Parasites most similar to Anaplasma bovis, Rickettsia rickettsii, Rickettsia sp. TwKM01, and at least seven apicomplexan species (including genera Cryptosporidium, Hepatozoon, and Theileria) were also identified. This study shows that A. phagocytophilum does occur in the hard tick in Taiwan, although whether R. haemaphysaloides can vector this pathogen remains to be determined. This work also reveals a high diversity of tick-borne bacteria and protozoans circulating in a small region and calls for further research on their potential risks for human health.

Differences in tick infestation of Tunisian sheep breeds

Different infestation patterns by ixodid ticks were studied in three sheep breeds in Tunisia: Barbarine, Queue Fine de l'Ouest and their cross-bred animals. During one year, 700 sheep were monitored and examined for tick infestation. A total of 722 ticks were collected from sheep ears. The most frequent tick species was by far Rhipicephalus sanguineus sensu lato (99%) and there were few specimens of Rhipicephalus bursa (1%) (p < 0.001). Overall infestation prevalence was estimated at 10.4%. The lowest infestation prevalence was in Barbarine sheep (7.3%), followed by Queue Fine de l'Ouest (16.7%) and the highest prevalence was in cross-bred sheep (19.1%) (p < 0.001). Mean overall infestation intensity was 1.6 ticks/sheep: lowest in Barbarine (1.4), followed by Queue Fine de l'Ouest (1.7) and cross-bred sheep (1.8). Similarly, abundance was lowest in Barbarine sheep (0.1), and was 0.3 in Queue Fine de l'Ouest and cross-bred animals. The results demonstrated a reduced infestation, possibly due to reduced attractiveness and/or increased resistance to tick infestation, of the Barbarine breed compared with the other two breeds. Further behavioural, genetic and molecular studies are needed to explain the mechanisms for the lower infestation indicators.

Anaplasma spp. in North Africa: A review on molecular epidemiology, associated risk factors and genetic characteristics

The genus Anaplasma belonging to the Anaplasmataceae family (order Rickettsiales) comprises obligate intracellular Gram-negative bacteria of veterinary and public health importance. Six species and five types of strains genetically related are currently assigned to the genus Anaplasma including Anaplasma marginale, A. centrale, A. bovis, A. phagocytophilum, A. ovis and A. platys as classified species, and "A. capra", A. odocolei sp. nov., A. phagocytophilum-like 1 (Anaplasma sp.-Japan), A. phagocytophilum-like 2 (Anaplasma sp.-China) and A. platys-like (also named Candidatus Anaplasma camelii) as unclassified strains. Most of these Anaplasma species and strains have been molecularly identified in several animal and/or tick species in the north of Africa. The aim of this review is to summarize the current knowledge about molecular epidemiology, associated risk factors and genetic diversity of Anaplasma species and related strains infecting animals and/or their incriminated tick vectors in North Africa. All these data should be considered when establishing of common management and control programs for anaplasmosis infecting humans and different animal species in North African countries.

GroEL typing and phylogeny of Anaplasma species in ticks from domestic and wild vertebrates

Anaplasma species are globally distributed tick-borne bacteria causing a range of clinical conditions in domestic animals, wildlife, and human. Nevertheless, data on presence and distribution of Anaplasma strains in ticks are still lacking, especially in the Mediterranean region. This study reports the molecular identification, genetic characterization and phylogeny of Anaplasma strains of both veterinary and zoonotic importance in ticks collected from domestic and wild hosts sampled in a typical Mediterranean warm temperate region, the island of Sardinia. Results reveal the presence of A. ovis in Rhipicephalus bursa and R. sanguineus sensu lato ticks; A. platys-like was found in R. bursa ticks; while A. platys and A. phagocytophilum were detected in Hyalomma marginatum and H. lusitanicum ticks. Investigating the occurrence of different Anaplasma species in ticks from domestic and wild hosts improves the knowledge of tick-borne diseases in the Mediterranean area, and has implications in defining vector species distribution and risk assessment.

Occurrence of four Anaplasma species with veterinary and public health significance in sheep, northwestern China

The members of the genus Anaplasma are important tick-borne rickettsial bacteria of veterinary and public health significance. Domestic ruminants are important reservoir hosts for several Anaplasma species. In this study, the occurrence of Anaplasma spp. was investigated by PCR in domestic small ruminants from Gansu, northwestern China. The results showed a high prevalence of Anaplasma spp. (46.2%, 201/435) in sheep. The average infection rates were 5.7%, 24.4%, 28.0% and 18.2% for A. ovis, A. bovis, A. phagocytophilum and A. capra, respectively. Coinfection of different Anaplasma species occurred in 96 (22.1%) sheep. The infections of Anaplasma species in sheep were confirmed by sequencing of msp4, 16S rRNA and gltA genes. Sequence analysis revealed a novel A. capra genotype in sheep that was distinct from the isolates identified from patients in northeastern China. This study gives the first insight of presence of four distinct Anaplasma species with veterinary and medical significance in sheep in northwestern China.

Identification of Anaplasma ovis appendage-associated protein (AAAP) for development of an indirect ELISA and its application

Background

Ovine anaplasmosis is a tick-borne disease that is caused by Anaplasma ovis in sheep and goats. The pathogen is widely distributed in tropical and subtropical regions of the world. At present, diagnosis of the disease mainly depends on microscopy or nucleic acid based molecular tests, although a few serological tests have been applied for the detection of A. ovis infection.

Results

Here we describe the identification of an A. ovis protein that is homologous to the A. marginale appendage-associated protein (AAAP). We expressed a recombinant fragment of this protein for the development of an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of A. ovis. Anaplasma ovis-positive serum showed specific reactivity to recombinantly expressed AAAP (rAAAP), which was further confirmed by the rAAAP ELISA, which also demonstrated no cross-reactivity with sera from animals infected with A. bovis or other related pathogens in sheep and goats. Testing antibody kinetics of five experimentally infected sheep for 1 year demonstrated that the rAAAP ELISA is suitable for the detection of early and persistent infection of A. ovis infections. Investigation of 3138 field-collected serum samples from 54 regions in 23 provinces in China demonstrated that the seroprevalence varied from 9.4% to 65.3%, which is in agreement with previous reports of A. ovis infection.

Conclusions

An A. ovis derived antigenic protein, AAAP, was identified and the antigenicity of the recombinant AAAP was confirmed. Using rAAAP an indirect ELISA assay was established, and the assay has been proven to be an alternative serological diagnostic tool for investigating the prevalence of ovine anaplasmosis of sheep and goats.

Bacterial arthropod-borne diseases in West Africa

Arthropods such as ticks, lice, fleas and mites are excellent vectors for many pathogenic agents including bacteria, protozoa and viruses to animals. Moreover, many of these pathogens can also be accidentally transmitted to humans throughout the world. Bacterial vector-borne diseases seem to be numerous and very important in human pathology, however, they are often ignored and are not well known. Yet they are in a phase of geographic expansion and play an important role in the etiology of febrile episodes in regions of Africa. Since the introduction of molecular techniques, the presence of these pathogens has been confirmed in various samples from arthropods and animals, and more rarely from human samples in West Africa. In this review, the aim is to summarize the latest information about vector-borne bacteria, focusing on West Africa from 2000 until today in order to better understand the epidemiological risks associated with these arthropods. This will allow health and veterinary authorities to develop a strategy for surveillance of arthropods and bacterial disease in order to protect people and animals.

A rapid, simple and sensitive loop-mediated isothermal amplification method to detect Anaplasma bovis in sheep and goats samples

A loop-mediated isothermal amplification (LAMP) technique has been widely used in detecting the nucleic acid of various pathogenic bacteria. In this study, a set of four LAMP primers was designed to specifically test Anaplasma bovis. The LAMP assay was performed at 62°C for 60min in a water bath. The specificity was confirmed by amplifying A. bovis isolate, while no cross reaction was observed with other five pathogens (Anaplasma bovis, Anaplasma phagocytophilum, Theileria luwenshuni, Babesia motasi and Schistosoma japonicum). The sensitivity of LAMP was 5×10⁰copies/μL, 100 times more than that of conventional PCR (5×10²copies/μL). Of 120 blood DNA extracted from sheep and goats field samples, 81 (67.5%), 22 (18.3%) and 43 (35.8%) were positively detected by LAMP, conventional PCR and nested PCR, respectively. The findings indicated that the developed LAMP assay is a new convenient tool for rapid and cost-effective detection of A. bovis.

Anaplasma marginale and A. phagocytophilum in cattle in Tunisia

Background

Tick-borne diseases caused by Anaplasma species put serious constraints on the health and production of domestic cattle in tropical and sub-tropical regions. After recovering from a primary infection, cattle typically become persistent carriers of pathogens and play a critical role in the epidemiology of the disease, acting as reservoirs of the Anaplasma spp.

Methods

In this study a duplex PCR assay was used for the simultaneous detection of Anaplasma marginale and Anaplasma phagocytophilum in cattle using two primer pairs targeting msp4 and msp2 genes, respectively. We used this method to analyze DNA preparations derived from 328 blood cattle samples that were collected from 80 farms distributed among Tunisia’s four bioclimatic zones.

Results

The prevalence of the A. marginale infection (24.7 %) was significantly higher and more widespread (in all bioclimatic areas) than that of A. phagocytophilum (0.6 %), which was found in a mixed infection with A. marginale.

Conclusions

The duplex PCR assay used proved to be a rapid, specific and inexpensive mean for the simultaneous detection of Anaplasma marginale and Anaplasma phagocytophilum in cattle blood. It allowed us to report the identification of A. phagocytophilum for the first time in cattle in Tunisia and confirm the presence of A. marginale in cattle from several geographical areas of the country. Further epidemiological studies undertaken using this assay will help improve the surveillance of the associated diseases in the regions where they are endemic.

First molecular survey and identification of Anaplasma spp. in white yaks (Bos grunniens) in China

Anaplasmosis is caused by a group of obligate intracellular bacteria in the genus Anaplasma, which are transmitted by ticks and infect humans, domestic animals and wildlife. This study was conducted to determine the prevalence and molecular characterization of Anaplasma spp. in semi-wild white yaks sampled in Tianzhu Tibetan Autonomous County, northwest China. Out of 332 samples tested, 35 (10·9%) were positive for Anaplasma spp. The positive rates were 6·2% (20/322) and 5·3% (17/322) for Anaplasma bovis and Anaplasma phagocytophilum in white yaks, respectively. None of the sample was positive for Anaplasma marginale. Two (0·6%) samples were simultaneously positive to A. bovis and A. phagocytophilum. Sequence analysis of the 16S rRNA gene revealed two genotypes (ApG1 and ApG2) of A. phagocytophilum and two sequence types (ST1 and ST2) of A. bovis in white yaks. This study is the first to document the presence of Anaplasma in white yaks. Our findings extend the host range for Anaplasma species and provide more valuable information for the control and management of anaplasmosis in white yaks.

Alpha proteobacteria of genusAnaplasma(Rickettsiales: Anaplasmataceae): Epidemiology and characteristics ofAnaplasmaspecies related to veterinary and public health importance

TheAnaplasmaspecies are important globally distributed tick-transmitted bacteria of veterinary and public health importance. These pathogens, cause anaplasmosis in domestic and wild animal species including humans.Rhipicephalus, Ixodes, DermacentorandAmblyommagenera of ticks are the important vectors ofAnaplasma.Acute anaplasmosis is usually diagnosed upon blood smear examination followed by antibodies and nucleic acid detection. All age groups are susceptible but prevalence increases with age. Serological cross-reactivity is one of the important issues amongAnaplasmaspecies. They co-exist and concurrent infections occur in animals and ticks in same geographic area. These are closely related bacteria and share various common attributes which should be considered while developing vaccines and diagnostic assays. Movement of susceptible animals from non-endemic to endemic regions is the major risk factor of bovine/ovine anaplasmosis and tick-borne fever. Tetracyclines are currently available drugs for clearance of infection and treatment in humans and animals. Worldwide vaccine is not yet available. Identification, elimination of reservoirs, vector control (chemical and biological), endemic stability, habitat modification, rearing of tick resistant breeds, chemotherapy and tick vaccination are major control measures of animal anaplasmosis. Identification of reservoirs and minimizing the high-risk tick exposure activities are important control strategies for human granulocytic anaplasmosis.