Serologic cross-reactivity between Anaplasma marginale and Anaplasma phagocytophilum

Does parity order or cow antibody level influence the humoral immunity of calves for cattle anaplasmosis?

Anaplasmosis is a widely distributed vector-borne disease of cattle caused by the bacteria Anaplasma marginale, which may lead to severe losses in beef and dairy cattle production. Anecdotal information among farmers suggested that some cows may deliver calves more resilient to anaplasmosis. To investigate this, we tested two hypotheses: (i) whether the parity order or (ii) cow antibody levels may influence the humoral immunity of pre-weaning calves against cattle anaplasmosis. For this study, we sampled 170 cattle (Bos taurus taurus, Angus breed) on a farm in Southern Brazil, comprising 85 cows (50 multiparous and 35 primiparous) and their 85 calves (50 days old). Antibodies against A. marginale were investigated using iELISA. Eighty percent of the animals were considered seropositive (100% of the cows and 60% of the calves). There was no significant difference in seroprevalence between calves from primiparous and multiparous cows. However, calves from multiparous cows exhibited higher antibody levels. To address the second question, we classified cows based on their antibody levels to A. marginale (high or low). Calves from cows with high antibody levels also showed elevated antibody levels against A. marginale. Furthermore, calves from cows with high antibody levels had approximately four times greater odds of being seropositive for A. marginale at 50 days old than those born to mothers with low antibody levels. In conclusion, the calf's antibody level against A. marginale appears to be related to the cow's parity order and the mother's antibody level.

PREVALENCE OF EHRLICHIA AND ANAPLASMA SPP. IN TICKS COLLECTED FROM CATTLE AND DEER IN ARKANSAS, USA

Bovine anaplasmosis, caused by Anaplasma marginale, is widespread in cattle in the southeast United States. The pathogen is biologically transmitted by Dermacentor spp. ticks, and mechanically transmitted by biting flies and via fomites. Despite high reported regional seroprevalence, Dermacentor spp. are rare on cattle in the southeast. To identify other putative An. marginale vectors, and to characterize cattle exposure to other tick-borne pathogens, we collected ticks from Arkansas cattle herds in 2020-2022. Recognizing that deer are important hosts for some of the same tick species that parasitize cattle, we also collected ticks from hunter-killed deer in the fall and winter of 2021. Ticks were screened for bacteria in the family Anaplasmataceae using qPCR. Positive samples were further amplified using a PCR assay targeting the groEL gene, and the resulting amplicons were sequenced for identification. A total of 3,794 ticks were collected, the majority of which were Amblyomma americanum. Amblyomma americanum was the most common species on cattle, and Ixodes scapularis was most common on deer. No ticks were positive for An. marginale, though Anaplasma phagocytophilum was detected in deer-collected I. scapularis, as well as in a single engorged Am. americanum from cattle. Amblyomma americanum from cattle were infected with Ehrlichia ewingii, Ehrilichia chaffeensis, and Panola Mountain Ehrlichia. Cattle in Arkansas are exposed to several ehrlichial pathogens and may also be exposed to An. phagocytophilum. The importance of these pathogens, particularly Panola Mountain Ehrlichia, in causing cattle disease in Arkansas deserves further study, as does the importance of mechanical transmission of An. marginale in bovine anaplasmosis epidemiology.

Unravelling the diversity of Anaplasma species circulating in selected African wildlife hosts by targeted 16S microbiome analysis

Organisms in the genus Anaplasma are obligate intracellular alphaproteobacteria. Bovine anaplasmosis, predominantly caused by Anaplasma marginale, is the most prevalent tick-borne disease (TBD) of cattle worldwide. Other Anaplasma species are known to cause disease; these include A. ovis, A. platys in dogs, A. capra in goats and humans, and A. phagocytophilum in humans. The rapid advancement of next-generation sequencing technologies has led to the discovery of many novel sequences ascribed to the genus Anaplasma, with over 20 putative new species being proposed since the last formal organization of the genus. Most 16S rRNA gene surveys for Anaplasma were conducted on cattle and to a lesser extent on rodents, dogs, and ticks. Little is known about the occurrence, diversity, or impact of Anaplasma species circulating in wildlife species. Therefore, we conducted a 16S rRNA gene survey with the goal of identifying Anaplasma species in a variety of wildlife species in the Kruger National Park and neighbouring game reserves, using an unbiased 16S rRNA gene microbiome approach. An Anaplasma/Ehrlichia-group specific quantitative real-time PCR (qPCR) assay revealed the presence of Anaplasma and/or Ehrlichia species in 70.0% (21/30) of African buffalo, 86.7% (26/30) of impala, 36.7% (11/30) of greater kudu, 3.2% (1/31) of African wild dog, 40.6% (13/32) of Burchell's zebra, 43.3% (13/30) of warthog, 22.6% (7/31) of spotted hyena, 40.0% (12/30) of leopard, 17.6% (6/34) of lion, 16.7% (5/30) of African elephant and 8.6% (3/35) of white rhinoceros samples. Microbiome sequencing data from the qPCR positive samples revealed four 16S rRNA sequences identical to previously published Anaplasma sequences, as well as nine novel Anaplasma 16S genotypes. Our results reveal a greater diversity of putative Anaplasma species circulating in wildlife than currently classified within the genus. Our findings highlight a potential expansion of the Anaplasma host range and the need for more genetic information from other important genes or genome sequencing of putative novel species for correct classification and further assessment of their occurrence in wildlife, livestock and companion animals.

Presence of Anaplasma spp. and Their Associated Antibodies in the Swedish Goat Population

Anaplasmosis is a tick-borne disease that has a severe impact on livestock production and welfare. The aim of this pilot study was to investigate the presence of Anaplasma spp. and associated antibodies in a subset of the Swedish goat population. In 2020, six goat herds located in different parts of Sweden were visited and whole blood and serum samples were collected. The whole blood samples (n = 40) were analysed for the presence of Anaplasma phagocytophilum, A. ovis and A. capra using quantitative and conventional polymerase chain reaction (PCR). The serum samples (n = 59) were analysed for the presence of antibodies to Anaplasma spp. using a commercial competitive enzyme-linked immunosorbent assay, and the same analysis was carried out on additional serum samples previously collected in 2018, 2019 and 2020 (n = 166). One goat (2.5%) tested positive for the presence of A. phagocytophilum genetic material, while the seropositivity rate ranged from 20 to 71%, depending on the surveyed year and area. These results indicate widespread exposure to Anaplasma spp. in the Swedish goat population. To inform future risk assessments and control efforts, further research is warranted to determine the prevalence of anaplasmosis and its impact on goat farming in Sweden.

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.

Serological Analysis of IgG and IgM Antibodies against Anaplasma spp. in Various Animal Species of the Qinghai-Tibetan Plateau

Anaplasma genus infects the blood cells of humans and animals by biting, causing zoonotic anaplasmosis. However, limited data are available on carrier animals for Anaplasma spp. antibodies in the Qinghai−Tibetan Plateau Area. Therefore, a serological indirect ELISA diagnostic method based on the major surface protein 5 (MSP5), derived from Anaplasma phagocytophilum, was developed in this study to analyze both IgG and IgM antibodies of Anaplasma spp. in a total of 3952 animals from the Qinghai−Tibetan Plateau, including yaks (Bos grunniens), cows (Bos taurus), cattle (Bos taurus domesticus), Tibetan sheep (Ovis aries), horses (Equus ferus caballus), pigs (Sus domesticus), chickens (Gallus gallus domesticus), donkeys (Equus asinus), stray dogs (Canis sp.), and stray cats (Felis sp.). The results showed that recombinant MSP5 protein was expressed and was successfully used to establish the indirect ELISA methods. The overall positivity for Anaplasma IgG and IgM antibodies was 14.6% (578/3952) and 7.9% (312/3952), respectively, and a total of 123 animals (3.1%) were both IgG- and IgM-positive. Moreover, the most prevalent Anaplasma IgG positivity was exhibited by donkeys (82.5%), followed by stray dogs, Tibetan sheep, pigs, chickens, horses, yaks, cows, cattle, and stray cats. The analysis for IgM antibody positivity revealed that IgM positivity was the most prevalent in the stray dogs (30.1%), followed by horses, yaks, Tibetan sheep, cows, stray cats, and cattle. Moreover, the results revealed significant differences (p < 0.05) at different altitudes in Anaplasma-specific IgG in the yaks, Tibetan sheep, and horses, and in IgM in the yaks and Tibetan sheep. In conclusion, this study is the first to demonstrate that yaks, cows, cattle, Tibetan sheep, horses, donkeys, stray dogs, stray cats, pigs, and chickens living in the Qinghai−Tibet Plateau are carrier animals for Anaplasma spp. IgG or IgM antibodies. The current findings provide valuable current data on the seroepidemiology of anaplasmosis in China and for plateau areas of the world.

The first study on the seroprevalence of Anaplasma spp. in small ruminants and assessment of associated risk factors in North Egypt

Background and Aim

Ovine anaplasmosis is a rickettsial disease caused by Anaplasma spp. These Gram-negative intracellular bacteria are mainly transmitted by ticks and infected blood cells of caprine, ovine, and wild small ruminants. At present, epidemiological data on anaplasmosis in cattle, dogs, and camels in Egypt are available, but the data about Anaplasma spp. in sheep and goat are scarce. This study aimed to determine the seroprevalence of Anaplasma spp. in small ruminants and assess the associated risk factors.

Materials and Methods

A cross-sectional study was performed to investigate the seroprevalence of Anaplasma spp. in 300 sheep and 300 goats from four governorates in North Egypt using a commercial competitive enzyme-linked immunosorbent assays kit, and the associated risk factors for the infection were evaluated.

Results

Overall, the seroprevalence of anti-Anaplasma antibodies was 18.3% and 21.3% in sheep and goats, respectively. A multivariable logistic regression model was used to determine the association between risk factors and Anaplasma spp. infection.

Conclusion

Age, animal husbandry, acaricide use, tick infestation, and contact with cattle were the primary risk factors for Anaplasma seropositivity. This study confirms the presence of antibodies against Anaplasma spp. in small ruminants from Egypt. This is the first study to assess the associated risk factors for Anaplasma infection in small ruminants from Egypt. Further studies are needed to improve the understanding of the associated disease factors, facilitating the development of new procedures for control of anaplasmosis in livestock.

Serological and molecular surveys of Anaplasma spp. in Egyptian cattle reveal high A. marginale infection prevalence

BACKGROUND

Bovine anaplasmosis is an infectious disease with worldwide distribution. It spreads by various routes mainly through tick bites.

AIMS

This study aimed to investigate bovine related Anaplasma spp. in cattle from three northern governorates of Egypt by serological and molecular assays, to evaluate the associated risk factors and to analyze the phylogeny of revealed A. marginale isolates.

METHODS

During 2020, a total of 650 blood samples were collected from asymptomatic cattle in the governorates of Kafr El-Sheikh (n=240), Menofia (n=230), and Al-Gharbia (n=180). Sera samples were examined using the Anaplasma antibody test kit, cELISA v2. Blood genomic DNA of seropositive cattle was then examined by PCRs specific to A. marginale, A. centrale, and A. bovis. Selected positive samples were subjected to nucleotide sequencing. Risk factors (i.e. geographical area, breed, type of production, sex, age, herd size, season, husbandry system, tick infestation, and application of acaricides) were evaluated by logistic regression approach.

RESULTS

In total, 130 cattle (20%, 95% CI: 17.1-23.3) were recorded seropositive for Anaplasma species. Major risk factors associated with seropositivity were being crossbred, dairy cattle, aged more than 5 years, summer season, herd size of below 300, pasture grazing, tick infestation, and not being subjected to regular treatment with acaricides. By using species-specific PCR, only A. marginale was detected. Nucleotide sequencing showed the occurrence of two different msp4 genotypes.

CONCLUSION

This study shows the high prevalence of A. marginale in cattle of Kafr El-Sheikh, Al-Gharbia, and Menofia. However, the connection between Anaplasma species and their tick vectors remains unknown in Egypt and merits further investigations. Since these infections primarily spread through ixodid tick bites, effective ectoparasite control strategies, regular examination of cattle and successful chemoprophylaxis are recommended.

Assessment of Seroprevalence and Associated Risk Factors for Anaplasmosis in Camelus dromedarius

(1) Background: Anaplasmosis is an infectious disease in camels caused by an obligate intracellular bacterium that is transmitted by ticks. (2) Methods: A cross-sectional study was conducted during 2020 to study the seroprevalence of Anaplasma spp. among Camelus dromedarius in three governorates in Egypt and assess the associated risk factors. Serum samples from 365 camels were examined by a competitive enzyme-linked immunosorbent assay (cELISA) test. (3) Results: Overall, the seroprevalence of anaplasmosis among camels was 18.6%. Multivariable logistic regression was performed, and it was discovered that tick infestation, application of acaricides, grooming practice and body condition were potential risk factors for Anaplasma spp. infection (odds ratio > 1) in dromedary camels. In contrast, the locality in which the camels lived and their age were not significant effects with regard to the occurrence of anaplasmosis. (4) Conclusions: The current findings suggest that improvement of protective measures to limit the effects of the identified risk factors can help to reduce the spread of anaplasmosis among camels in Egypt.

Anaplasma phagocytophilum and Anaplasma ovis-Emerging Pathogens in the German Sheep Population

Knowledge on the occurrence of pathogenic tick-borne bacteria Anaplasma phagocytophilum and Anaplasma ovis is scarce in sheep from Germany. In 2020, owners from five flocks reported ill thrift lambs and ewes with tick infestation. Out of 67 affected sheep, 55 animals were clinically examined and hematological values, blood chemistry and fecal examinations were performed to investigate the underlying disease causes. Serological tests (cELISA, IFAT) and qPCR were applied to all affected sheep to rule out A. phagocytophilum and A. ovis as a differential diagnosis. Ticks were collected from selected pastures and tested by qPCR. Most animals (n = 43) suffered from selenium deficiency and endoparasites were detected in each flock. Anaplasma spp. antibodies were determined in 59% of examined sheep. Seventeen animals tested positive for A. phagocytophilum by qPCR from all flocks and A. phagocytophilum was also detected in eight pools of Ixodes ricinus. Anaplasma phagocytophilum isolates from sheep and ticks were genotyped using three genes (16S rRNA, msp4 and groEL). Anaplasma ovis DNA was identified in six animals from one flock. Clinical, hematological and biochemical changes were not significantly associated with Anaplasma spp. infection. The 16S rRNA analysis revealed known variants of A. phagocytophilum, whereas the msp4 and groEL showed new genotypes. Further investigations are necessary to evaluate the dissemination and health impact of both pathogens in the German sheep population particularly in case of comorbidities.

Molecular Detection and Phylogeny of Anaplasma phagocytophilum and Related Variants in Small Ruminants from Turkey

Simple Summary

We explored the existence of Anaplasma phagocytophilum and related variant in samples of goats and sheep obtained from Antalya and Mersin provinces, representative of Mediterranean region of Turkey. Based on 16S rRNA and groEL genes of A. phagocytophilum and related variants, we examined blood samples by polymerase chain reaction (PCR) followed by sequencing. The results showed that the prevalence of A. phagocytophilum and A. phagocytophilum-like 1 infection was 1.4% and 26.5%, respectively. Sequencing confirmed molecular data and showed the presence of A. phagocytophilum and A. phagocytophilum-like-1 variant in the sampled animals.

Abstract

Anaplasma phagocytophilum causes tick-borne fever in small ruminants. Recently, novel Anaplasma variants related to A. phagocytophilum have been reported in ruminants from Tunisia, Italy, South Korea, Japan, and China. Based on 16S rRNA and groEL genes and sequencing, we screened the frequency of A. phagocytophilum and related variants in 433 apparently healthy small ruminants in Turkey. Anaplasma spp. overall infection rates were 27.9% (121/433 analyzed samples). The frequency of A. phagocytophilum and A. phagocytophilum-like 1 infections was 1.4% and 26.5%, respectively. No A. phagocytophilum-like 2 was detected in the tested animals. The prevalence of Anaplasma spp. was comparable in species, and no significant difference was detected between sheep and goats, whereas the prevalence significantly increased with tick infestation. Sequencing confirmed PCR-RFLP data and showed the presence of A. phagocytophilum and A. phagocytophilum-like-1 variant in the sampled animals. Phylogeny-based on 16S rRNA gene revealed the A. phagocytophilum-like 1 in a separate clade together with the previous isolates detected in small ruminants and ticks. In this work, A. phagocytophilum-like 1 has been detected for the first time in sheep and goats from Turkey. This finding revealed that the variant should be considered in the diagnosis of caprine and ovine anaplasmosis.

Zoonotic Tick-Borne Pathogens in Temperate and Cold Regions of Europe-A Review on the Prevalence in Domestic Animals

Ticks transmit a variety of pathogens affecting both human and animal health. In temperate and cold regions of Europe (Western, Central, Eastern, and Northern Europe), the most relevant zoonotic tick-borne pathogens are tick-borne encephalitis virus (TBEV), Borrelia spp. and Anaplasma phagocytophilum. More rarely, Rickettsia spp., Neoehrlichia mikurensis, and zoonotic Babesia spp. are identified as a cause of human disease. Domestic animals may also be clinically affected by these pathogens, and, furthermore, can be regarded as sentinel hosts for their occurrence in a certain area, or even play a role as reservoirs or amplifying hosts. For example, viraemic ruminants may transmit TBEV to humans via raw milk products. This review summarizes the role of domestic animals, including ruminants, horses, dogs, and cats, in the ecology of TBEV, Borrelia spp., A. phagocytophilum, Rickettsia spp., N. mikurensis, and zoonotic Babesia species. It gives an overview on the (sero-)prevalence of these infectious agents in domestic animals in temperate/cold regions of Europe, based on 148 individual prevalence studies. Meta-analyses of seroprevalence in asymptomatic animals estimated an overall seroprevalence of 2.7% for TBEV, 12.9% for Borrelia burgdorferi sensu lato (s.l.), 16.2% for A. phagocytophilum and 7.4% for Babesia divergens, with a high level of heterogeneity. Subgroup analyses with regard to animal species, diagnostic test, geographical region and decade of sampling were mostly non-significant, with the exception of significantly lower B. burgdorferi s.l. seroprevalences in dogs than in horses and cattle. More surveillance studies employing highly sensitive and specific test methods and including hitherto non-investigated regions are needed to determine if and how global changes in terms of climate, land use, agricultural practices and human behavior impact the frequency of zoonotic tick-borne pathogens in domestic animals.

Prevalence of antibodies to Anaplasma in cattle and buffaloes of different organized herds in India

Bovine anaplasmosis is one of the most important tick borne disease in ruminants causing huge economic loss to the dairy industry. A cross-sectional study was carried out to detect serum antibodies to Anaplasma infection in cattle and buffaloes housed in 14 organized herds located at various climatic zones spreading over 9 different states in India. A total of 911 serum samples, collected from 667 cattle and 244 buffaloes, were subjected to a competitive enzyme linked immune-sorbent assay detecting an epitope of major surface protein 5 (MSP5) of Anaplasma. The overall true prevalence was 48.72% (95% CI 45.13-52.32%). The prevalence rate was higher in cattle (51.58%) than buffaloes (40.89%) and the difference was statistically significant (p < 0.05). Indigenous cattle (59.30%) showed higher seropositivity than crossbreed (57.16%) and exotic cattle breeds (42.28%). Although statistically not significant, female (52.37%) showed higher seropositivity than male (46.43%). Similarly, significant difference in prevalence (p < 0.05) was observed for animals reared in different climatic zones with highest prevalence recorded in arid zone (90.49%) and lowest in semi-arid zone (29.83%). Very wide variation in prevalence (9.95-100%) was recorded between farms. The present study indicates endemicity of Anaplasma in India, similar to other tropical and sub-tropical countries of the world. Endemic instability was recorded in some of the studied farms suggesting possibility of outbreak of new clinical cases resulting in economic loss. Therefore, suitable policies and procedures for prevention and control of Anaplasma infection should be adopted in these farms.

Molecular detection and genetic characterization of Anaplasma marginale and Anaplasma platys-like (Rickettsiales: Anaplasmataceae) in water buffalo from eight provinces of Thailand

Background

Anaplasmosis, an animal disease caused by rickettsial bacteria in the genus Anaplasma, is of considerable economic importance in livestock animals in many countries worldwide. The objectives of this study were to determine the identity, prevalence, and geographic distribution of Ehrlichia and Anaplasma in naturally infected water buffalo in Thailand using PCR amplification and sequencing of the 16S ribosomal RNA and heat shock protein groEL genes. A total of 456 buffalo blood samples from Thailand were investigated. Species identification and genetic differentiation of intra-population and inter-population with the global isolates were conducted based on nucleotide sequences. Interplay between the infection and host factors was also assessed.

Results

Overall, 41% of water buffalo were found to be infected with rickettsial organisms in the family Anaplasmataceae, but Ehrlichia spp., Neorickettsia spp., and Wolbachia spp. were not found in any of the sequenced samples in this study. Female buffalo were more frequently infected with bacteria in the family Anaplasmataceae than males [71 out of 176 females (40.3%) versus 11 out of 47 males (23.4%)]. The Odds Ratio value indicated that the risk of infection for female buffalo was 2.2-fold higher than that for males (p < 0.05). We detected three haplotypes of A. marginale 16S rRNA gene and they were placed in a clade that was closely related to the A. marginale in buffalo in China; and cattle in Thailand, Uganda, and China. Homology searching of groEL sequences against the GenBank™ database using the BLASTn algorithm revealed that the obtained sequences had a high percentage similarity (98.36–99.62%) to A. platys sequences. The groEL sequences of three A. platys-like isolates were clustered in the same clade as the A. platys from the tick Rhipicephalus microplus in China.

Conclusions

Our data showed that the apparently healthy buffalo were naturally infected by bacteria in the family Anaplasmataceae at a relatively high prevalence. We also report the finding of A. platys-like infections in water buffalo in Thailand for the first time. Water buffalo serving as the reservoir host of anaplasmosis is of concern for managing the disease control and prevention in ruminants.

Epidemiological and Comparative Diagnostic Study of Anaplasma Spp. Infection in Goats from North-Eastern Algeria

Anaplasmosis is an infectious disease affecting goats and other ruminants. Our goal was to estimate the prevalence of Anaplasma spp. infections, and to identify different tick species in goa ts along with their associated risk factors. The epidemiology of Anaplasma spp. (A. ovis/A. marginale) was investigated from April to September 2016 in dairy goats from three different agro-ecological areas in the northeast region of Algeria (Guelma and El-Taref). We tested 182 goat sera using a MSP5 competitive ELISA (cELISA) test for IgG antibody screening, and by microscopic examination using the Giemsa (May-Greunwald-Giemsa) stain of 128 blood smears to detect intraerythrocytic inclusions bodies. The results demonstrated a total infection rate of 78.02 % and 42.18 % using cELISA and MGG, respectively. Only two species of ticks collected were identified, i. e. Rhipicephalus sanguineus (85.39 %) and Rhipicephalus bursa (14.60 %). Our study revealed that factors, such as the season, the type of farming, the hygienic status and the climatic conditions of the studied areas were found to be significantly associated with the tick infestation of goats (P < 0.05). The Anaplasma spp. infection prevalence was found to be highly dependent on the climatic conditions, the season (P < 0.05) and most closely related to the type of breeding and herd management (P = 0.000).

The evaluation of the Giemsa technique showed specificity and sensitivity of 60.71 % and 45.16 % respectively. Calculating the concordance between the two techniques revealed Cohen’s Kappa value of 0.038 in the range 0.21—0.40, which corresponded to a very low agreement. The McNemar test results showed that both tests gave significantly different results (P < 0.05). This work provides evidence for Anaplasma spp. in goats from north-eastern Algeria.

Vector competence of Rhipicephalus sanguineus sensu stricto for Anaplasma platys

Anaplasma platys is a Gram-negative, obligate intracellular bacteria that causes canine infectious cyclic thrombocytopenia in dogs. The brown dog tick Rhipicephalus sanguineus sensu lato is presumed to be the vector of A. platys based on the overlap in distribution of R. sanguineus and A. platys infections, detection of A. platys DNA in both flat and engorged field-collected R. sanguineus, and the fact that dogs are primary hosts of both brown dog ticks and A. platys. However, the only study evaluating the vector competence of R. sanguineus for A. platys under controlled laboratory conditions reported an apparent inability of ticks to acquire or maintain the pathogen. In 2016, engorged female Rhipicephalus sanguineus sensu stricto ticks were collected off dogs to start a laboratory tick colony. After one generation of colony maintenance on tick-naïve and pathogen-free New Zealand White rabbits, a rabbit used to feed F1 adults seroconverted to Anaplasma phagocytophilum antigen. PCR and subsequent DNA sequencing identified the presence of A. platys in both the adult ticks fed on this rabbit and their resulting F2 progenies. Retrospective testing of all previous (P and F1) life stages of this colony demonstrated that the infection originated from one field-collected A. platys-infected female whose progeny was propagated in the laboratory and produced the PCR-positive F1 adults. Over the following (F2-F4) generations, the prevalence of A. platys in this colony reached 90-100 % indicating highly efficient transovarial and horizontal transmission, as well as transstadial maintenance, of this pathogen by R. sanguineus s.s.

Molecular epidemiology of Anaplasma spp. related to A. phagocytophilum in Mediterranean small ruminants

The genus Anaplasma currently comprises 6 bacterial species mostly pathogenic to animals and/or human, including the zoonotic species Anaplasma phagocytophilum, the causative agent of tick-borne fever (TBF) of ruminants, and of granulocytic anaplasmosis of horses, dogs and human. Recently, novel potentially non-pathogenic strains related to A. phagocytophilum have been identified in Japan, China, and Tunisia. This paper reports the identification, molecular typing, and evolutionary history of novel Anaplasma strains (A. phagocytophilum-like 1 and 2), related to but distinct from A. phagocytophilum in Mediterranean area of Europe and Africa. PCR-RFLP and phylogenetic analyses based on 16S rRNA provided evidence for the circulation of A. phagocytophilum-like 1 strains in Europe. Phylogeny based on groEL gene showed the inclusion of Sardinian and Tunisian A. phagocytophilum-like 1 strains in a unique clade distinct from, but related to that of Japanese strains. Results suggest that genetic diversity within the genus Anaplasma is much greater than expected and provide information useful for the development of specific and effective diagnostic and prophylactic tools.

Real-time PCR assay with an endogenous internal amplification control for detection and quantification of Anaplasma marginale in bovine blood

Bovine anaplasmosis is a tick-borne rickettsial disease, causing significant economic losses in many countries. The main causative agent of bovine anaplasmosis is Anaplasma marginale (Rickettsiales, Anaplasmataceae). To date, several PCR assays for A. marginale DNA detection were proposed, but most of them do not provide an internal amplification control, which allows to prevent false-negative results and is required for reliability of the results of pathogen DNA detection by PCR assay. In the present study, a real-time PCR assay based on the species-specific and highly conserved fragment of msp1α gene was developed for detection and quantification of A. marginale in bovine blood. The real-time PCR assay is able to detect as few as one copу of msp1α gene per reaction. To prevent false-negative results, simultaneous amplification and detection of the bovine genomic DNA fragment as an endogenous internal amplification control (IAC) was provided. The assay can be used as a highly specific and sensitive method for detection and quantification of A. marginale in infected cattle, and for the evaluation of the efficacy of anti-rickettsial drugs and anaplasmosis vaccines.

Factors associated with seroprevalence of bovine anaplasmosis in Mississippi, USA

Anecdotally, Veterinary Feed Directive prescriptions in the southeastern United States (U.S.) are written most often for treatment and prevention of bovine anaplasmosis (BA) but seroprevalence estimates and factors associated with this disease are currently unavailable in Mississippi (MS). Bovine anaplasmosis, a tick-borne disease of cattle caused by Anaplasma marginale, remains an economically important disease in U.S. The lack of recent seroprevalence of BA throughout the U.S. makes accurate assessment of production losses incurred by the cattle industry in the U.S. difficult, if not impossible to estimate. This study was aimed at determining the seroprevalence of and factors associated with BA in MS. Data were obtained from an active survey of 207 beef cows slaughtered between May 2013 and December, 2014 as well as from reviewing 5182 Veterinary Diagnostic Laboratories (VDLs) records of specimens from MS submitted for BA testing between 2002 and 2018. From the active surveillance, the overall observed apparent seroprevalence of BA in MS with cELISA was 28.99% (95% CI: 23.23 - 35.50%) while the estimated true seroprevalence was 29.02% (22.74 - 36.07%). However, from the laboratory records, the overall apparent period seroprevalence of BA in MS between 2002 and 2018 irrespective of diagnostic assay used was 16.72% (15.73 - 17.76%) and yearly increase in the diagnosis of BA followed a significant trend (P < 0.0001). With cELISA, the apparent seroprevalence of BA was 22.11% (20.78 - 23.49%) and the estimated true seroprevalence was 21.62% (20.18 - 23.11%). However, with CFT, the apparent seroprevalence of BA was 13.50% (10.75 - 16.81%) and the estimated true seroprevalence was 47.90% (36.30 - 61.87%). Factors associated with positive BA results were age, cattle type, and quarter of the year the specimens were submitted. The odds of the outcome were 22 as high in adults, 27 times as high in beef cattle, and 2 times as high between October to December in comparisons to juveniles, dairy cattle, and between April to June, respectively. Cattle population in the counties was not associated with positive BA results. Current records from the VDLs appear to accurately estimate the seroprevalence of BA in MS and thus serves as a reliable surveillance tool BA in the state. Because the burden of BA appears to be distributed throughout the state, future prevention and control measures for BA should focus on the identified putative risk factors and be intensified throughout MS.

Real-Time Diagnostics of Anaplasmosis in Cattle by PCR Method

The purpose of the research is real-time development of PCR method for diagnostics of anaplasmosis in cattle. Materials and methods. For real time development of primers and fluorescence-labeled probe for PCR msp1α gene sequences 57 isolates Anaplasma marginale available on database Genbank (http://www.ncbi.nlm.nih.gov/genbank/) were used. Conservative areas of msp1α gene were revealed with Сlustal Omega programme (https://www.ebi.ac.uk/Tools/msa/clustalo/). Specificity of primers and probe were checked experimentally in silico using BLASTN programme (http://blast.ncbi.nlm.nih.gov/Blast.cgi) on the animals’ blood samples infected by Anaplasma A. ovis, A. centrale, A. bovis, A. phagocytophilum and A. platys, and sequence analysis of amplicon by Sanger’s method. pGEM-msp1α plasmid designed by us containing msp1α gene fragment with a length of 207 bps was used to assess of sensitivity of the method. Results and discussion. PCR method has been developed in real time mode to detect A. marginale anaplasmosis agent in cattle. Primers and fluorescence-labeled probe have been developed to amplify and detect msp1α gene fragment with a length of 207 bps and PCR conditions have been optimized. Sensitivity of the method allows to detect one copy of msp1а gene copy of А. marginale in analysed DNA sample. Specificity of method allows to differentiate A. marginale from other anaplasma types (A. ovis, A. bovis, A. centrale, A. phagocytophilum, A. platys). The developed method can be used to detect and assess А. Marginale quantitatively in blood samples of infected animals in order to prove the diagnosis as well as to perform epizootological monitoring of anaplasmosis in cattle.

Factors associated with seroprevalence of bovine anaplasmosis in Texas

Bovine anaplasmosis (BA), caused by Anaplasma marginale, is an economically important tick-borne disease of cattle in the United States (U.S.) and worldwide. Anecdotally, Veterinary Feed Directive prescriptions in the southeastern U.S. are written mostly for treatment/prevention of BA. However, there are no recent temporal seroprevalence estimates of BA in Texas (TX). Thus, this study was aimed at determining the seroprevalence of and factors associated with BA in TX. Data were obtained from an active slaughter survey (n = 215) performed between August and December 2014 as well as from reviewing Texas A&M Veterinary Medical Diagnostic Laboratories (TVMDLs) records of specimens submitted for BA testing from January 2002 to June 2012 (n = 15,460). Irrespective of the assay used, the overall apparent seroprevalence of BA in TX between 2002 and 2012 was 15.91% (95% CI: 15.34 - 16.50%) and the yearly increase in seroprevalence followed a significant trend (P < .0001). With cELISA, the apparent seroprevalence of BA was 13.49% (95% CI: 9.56 - 18.7%) and 13.02% (95% CI: 9.74 - 17.18%) for the slaughter survey and TVMDLs records between October and December 2011, respectively. Whereas the estimated true seroprevalence for the same period was 12.35% (95% CI: 8.04 - 18.05%) and 12.78% (95% CI: 9.19 - 17.30%), respectively. Factors associated with positive BA results were age, breed, diagnostic assay used, year and quarter of the year the specimens were submitted. The odds of the outcome were 1.5 times as high when cattle were adults (vs juvenile). In comparison to other breeds, the odds of the outcome were 11.57, 7.16, and 2.5 times higher in Hereford, Angus, and mixed breeds, respectively. When compared to 2003, the odds of the diagnosis of BA was approximately 2 times as high in 2010 but 3 times as high in 2002, 2005, and 2011 and approximately 4 times as high in 2006 and 2007. In comparison to the duration from October to December, the odds of the outcome were approximately 1.5 as high from January to March and from July to September durations. Counties with specimen submissions for BA testing had a significantly greater cattle population (p = .0061) and number of cattle farms (p < .001) than counties without specimen submissions. Subsequent prevention and control measures for BA should target these factors and should prioritize on counties with higher cattle population in the eastern part of TX. Furthermore, TVMDLs records appear sufficient for the surveillance of BA in TX.

Prevalence of Anaplasma bovis in Canadian populations of the Rocky Mountain wood tick, Dermacentor andersoni

PCR and DNA sequencing were used to determine the prevalence of Anaplasma bovis in Rocky Mountain wood ticks (Dermacentor andersoni) collected in Alberta and Saskatchewan, Canada. These analyses revealed that A. bovis DNA was present in 35 (2.1%) of 1679 ticks collected at 12 of the 24 localities. The discovery of A. bovis in host-seeking female and male D. andersoni from multiple locations in southern Canada may have important implications for diagnosis of anaplasmosis in Canada.

Factors associated with Seroprevalence of Anaplasma marginale in Kentucky cattle

Bovine anaplasmosis (BA) is tick-borne disease of cattle caused by Anaplasma marginale and it remains an economically important disease in the United States (U.S.). We have anecdotal information that Veterinary Feed Directive prescriptions in Kentucky (KY) are written most often for treatment and prevention of BA. However, there are no recent prevalence estimates of this disease in KY. Thus, this study was aimed at determining the seroprevalence of and factors associated with BA in KY. Data were obtained from an active slaughter survey (n = 232) performed between May and July 2013 as well as from reviewing The University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) records of specimens submitted for BA testing from 2002-2012 (n = 2,573). With competitive ELISA, the apparent prevalence of BA in KY was 10.78% (95% CI: 7.41-15.42%) and 11.58% (95% CI: 10.31-12.98%) for the slaughter survey and laboratory records, respectively. Whereas the estimated true prevalence was 9.44% (95% CI: 5.65-14.48%) and 10.3% (95% CI: 8.92-11.8%), respectively. From the laboratory records, factors associated with positive BA results were age, breed, whether specimens were submitted singularly or as a group, year and quarter of the year the specimens were submitted. The odds of the outcome were 5 times as high when cattle were adults (vs juvenile) and almost 4 times as high when specimens were submitted singularly (vs group). In comparison to Holstein breed, the odds of the outcome were 3.5 and 2.5 times higher in Angus and mixed breeds, respectively. The odds of a diagnosis of BA varied in an undulating pattern by year of sample submission. When compared to 2011, the odds of a diagnosis of BA was approximately 3 times as high in 2005, 2008, and 2009 and approximately 5 times as high in 2004, 2006, and 2012. In comparison to the duration from January to March, the odds of the outcome were almost 20 times as high from July to September but 10 times as high from October to December durations. Counties with specimen submissions for BA testing had a significantly greater cattle population and number of cattle farms than counties without specimen submissions. Future prevention and control measures for BA should target these factors and should be weighted more on counties with higher cattle population. Furthermore, current records from the UKVDL appear sufficient for the surveillance of BA in KY.

Bovine anaplasmosis and tick-borne pathogens in cattle of the Galapagos Islands

A cross-sectional study was conducted to determine the species of Anaplasma spp. and estimate its prevalence in cattle of the three main cattle-producing Galapagos Islands (Santa Cruz, San Cristóbal and Isabela) using indirect PCR assays, genetic sequencing and ELISA. Ticks were also collected from cattle and scanned for 47 tick-borne pathogens in a 48 × 48 real-time PCR chip. A mixed effects logistic regression was performed to identify potential risk factors explaining Anaplasma infection in cattle. A. phagocytophilum was not detected in any of the tested animals. Genetic sequencing allowed detection of A. platys-like strains in 11 (36.7%) of the 30 Anaplasma spp.-positive samples analysed. A. marginale was widespread in the three islands with a global between-herd prevalence of 100% [89; 100]_{95% CI} and a median within-herd prevalence of 93%. A significant association was found between A. marginale infection and age with higher odds of being positive for adults (OR = 3.3 [1.2; 9.9]_{95% Bootstrap CI} ). All collected ticks were identified as Rhipicephalus microplus. A. marginale, Babesia bigemina, Borrelia theileri and Francisella-like endosymbiont were detected in tick pools. These results show that the Galapagos Islands are endemic for A. marginale.

Estimated seroprevalence of Anaplasma spp. and spotted fever group Rickettsia exposure among herders and livestock in Mongolia

BACKGROUND

To better understand the epidemiology of tick-borne disease in Mongolia, a comprehensive seroprevalence study was conducted investigating exposure to Anaplasma spp. and spotted fever group (SFG) Rickettsia spp. in nomadic herders and their livestock across three provinces from 2014 to 2015.

METHODS

Blood was collected from 397 herders and 2370 livestock, including sheep, goats, cattle, horses and camels. Antibodies against Anaplasma spp. and SFG Rickettsia were determined by indirect immunofluorescence using commercially available slides coated with Anaplasma phagocytophilum and Rickettsia rickettsii antigens. Logistic regression was used to determine if the odds of previous exposure differed by gender, location, and species, with or without adjustment for age. To examine the association between seroprevalence and environmental variables we used ArcGIS to circumscribe the five major clusters where human and animal data were collected.

RESULTS

Anaplasma spp. exposure was detected in 37.3% (136/365) of humans and 47.3% (1120/2370) of livestock; SFG Rickettsia exposure was detected in 19.5% (73/374) humans and 20.4% (478/2342) livestock. Compared to the southern province (aimag) of Dornogovi, located in the Gobi Desert, humans were significantly more likely to be exposed to Anaplasma spp. and SFG Rickettsia in the northern provinces of Tov (OR=7.3, 95% CI: 3.5, 15.1; OR=3.3, 95% CI: 1.7, 7.5), and Selenge (OR=6.9, 95% CI: 3.4, 14.0; OR=2.2, 95% CI: 1.1, 4.8).

CONCLUSION

The high seroprevalence of Anaplasma spp. and SFG Rickettsia in humans and livestock suggests that exposure to tick-borne pathogens may be common in herders and livestock in Mongolia, particularly in the more northern regions of the country. Until more is known about these pathogens in Mongolia, physicians and veterinarians in the countryside should consider testing for Anaplasma and SFG Rickettsia infections and treating clinically compatible cases, while public health authorities should expand surveillance efforts for these emerging infections.

Molecular detection of tick-borne pathogens in cattle from Southwestern Ethiopia

Tick-borne diseases (TBDs) cause significant losses among livestock and impact the livelihoods of resource-poor farming communities worldwide. In Ethiopia, detailed studies on the epidemiology of tick-borne pathogens (TBPs) in cattle using sensitive molecular detection methods are scarce. The objective of this study was to determine the prevalence and species composition of bovine TBPs of veterinary significance in local cattle populations. A comprehensive cross-sectional epidemiological study was conducted in cattle populations of Illubabor zone in Southwestern Ethiopia from June to August 2013. For this purpose, blood samples were collected from 392 cattle. A combination of polymerase chain reaction (PCR) and a Reverse Line Blot (RLB) hybridization assay was employed for the detection of TBPs in these samples. The PCR/RLB results of the 392 blood samples indicated a high overall prevalence of 96.9% for TBPs, including Theileria mutans (66.1%), Theileria orientalis (51.8%), Anaplasma sp. Omatjenne (25.5%), Anaplasma marginale (14.5%), Babesia bigemina (14.0%) and Theileria velifera (13.0%) and minor occurrences of Ehrlichia ruminantium (0.5%) and Ehrlichia minasensis (0.26%). Moreover, three novel Anaplasma genotypes were detected in bovine blood samples. A phylogenetic analysis revealed that they most likely represent three, but at least two, new species. The prevalence of the three novel Anaplasma species, preliminary designated as Anaplasma sp. Hadesa, Anaplasma sp. Saso and Anaplasma sp. Dedessa, was 12.5%, 14.3% and 5.6%, respectively. Overall, a total of 227 cattle (57.9%) were found to be co-infected with two or more TBPs simultaneously and 86 different species combinations were observed. The findings show a very high burden of infection of cattle with TBPs in Ethiopia. The high frequency of co-infections suggests that clinical manifestations might be complex. Further research is required to determine the pathogenicity, host cell types and vector of the three novel Anaplasma species identified in this study.

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.

"Candidatus anaplasma camelii" in one-humped camels (Camelus dromedarius) in Morocco: a novel and emerging anaplasma species?

Background

There has been a growing interest in camel anaplasmosis due to its recent emergence in this reservoir species and concerns for its zoonotic potential. The epidemiology of anaplasmosis in camels therefore remains poorly understood mostly because camels belong to marginalised poor and often transhumant populations whose interests are largely neglected. Most studies of anaplasmosis in camels have relied on microscopy and serology for diagnosis and only three studies, undertaken in Tunisia, Saudia Arabia and China, have used molecular diagnostics. The present work characterises Anaplasmataceae strains circulating in the Camelus dromedarius reservoir in Morocco using PCR.

Methods

Camels (n = 106) were randomly sampled from 6 regions representing different agro-ecological areas in southern Morocco. Whole blood was collected and screened using PCR methods targeting the gene groEL. Anaplasmataceae strains were characterised by sequence analysis of the gene groEL.

Results

A total of 39.62% (42/106) camels screened were positive for Anaplasmataceae spp. GenBank BLAST analysis of five positive sequenced samples revealed that all strains were 100% identical to “Candidatus Anaplasma camelii”. Phylogenetic investigation and genetic characterisation of the aligned segment (650 bp) of the gene groEL confirmed high similarity with A. platys.

Conclusion

This study demonstrates the circulation of a previously unidentified species of the genus Anaplasma in Morocco which is genetically close to the agent causing canine anaplasmosis but whose main reservoir is thought to be Camelus dromedarius.

Trial registration number

This study is not a clinical trial and therefore a trial registration number does not apply.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0216-8) contains supplementary material, which is available to authorized users.

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.

Serologic screening for 13 infectious agents in roe deer (Capreolus capreolus) in Flanders

Introduction

In order to investigate the role of roe deer in the maintenance and transmission of infectious animal and human diseases in Flanders, we conducted a serologic screening in 12 hunting areas.

Materials and methods

Roe deer sera collected between 2008 and 2013 (n=190) were examined for antibodies against 13 infectious agents, using indirect enzyme-linked immunosorbent assay, virus neutralisation, immunofluorescence, or microagglutination test, depending on the agent.

Results and discussion

High numbers of seropositives were found for Anaplasma phagocytophilum (45.8%), Toxoplasma gondii (43.2%) and Schmallenberg virus (27.9%), the latter with a distinct temporal distribution pattern following the outbreak in domestic ruminants. Lower antibody prevalence was found for Chlamydia abortus (6.7%), tick-borne encephalitis virus (5.1%), Neospora caninum (4.8%), and Mycobacterium avium subsp paratuberculosis (4.1%). The lowest prevalences were found for Leptospira (1.7%), bovine viral diarrhoea virus 1 (1.3%), and Coxiella burnetii (1.2%). No antibodies were found against Brucella sp., bovine herpesvirus 1, and bluetongue virus. A significant difference in seroprevalence between ages (higher in adults >1 year) was found for N. caninum. Four doubtful reacting sera accounted for a significant difference in seroprevalence between sexes for C. abortus (higher in females).

Conclusions

Despite the more intensive landscape use in Flanders, the results are consistent with other European studies. Apart from maintaining C. abortus and MAP, roe deer do not seem to play an important role in the epidemiology of the examined zoonotic and domestic animal pathogens. Nevertheless, their meaning as sentinels should not be neglected in the absence of other wild cervid species.

Molecular and serological in-herd prevalence of Anaplasma marginale infection in Texas cattle

Bovine anaplasmosis is an infectious, non-contagious disease caused by the rickettsial pathogen Anaplasma marginale (A. marginale). The organism has a global distribution and infects erythrocytes, resulting in anemia, jaundice, fever, abortions and death. Once infected, animals remain carriers for life. The carrier status provides immunity to clinical disease, but is problematic if infected and naïve cattle are comingled. Knowledge of infection prevalence and spatial distribution is important in disease management. The objective of this study was to assess A. marginale infection in-herd prevalence in Texas cattle using both molecular and serological methods. Blood samples from 11 cattle herds within Texas were collected and analyzed by reverse transcription quantitative real-time PCR (RT-qPCR) and a commercial competitive enzyme-linked immunosorbent assay (cELISA). Samples from experimentally infected animals were also analyzed and RT-qPCR detected A. marginale infection up to 15 days before cELISA, providing empirical data to support the interpretation of herd prevalence results. Herds with high prevalence were located in the north Texas Rolling Plains and west Trans-Pecos Desert, with RT-qPCR prevalence as high as 82% and cELISA prevalence as high as 88%. Overall prevalence was significantly higher in cattle in north and west Texas compared to cattle in east Texas (p<0.0001 for prevalence based on both RT-qPCR and cELISA). The overall RT-qPCR and cELISA results exhibited 90% agreement (kappa=0.79) and provide the first A. marginale infection prevalence study for Texas cattle using two diagnostic methods. Since cattle are the most important reservoir host for A. marginale and can serve as a source of infection for tick and mechanical transmission, information on infection prevalence is beneficial in the development of prevention and control strategies.

Can Anaplasma ovis in small ruminants be neglected any longer?

Anaplasma species are obligate intracellular rickettsial pathogens transmitted by ticks with an impact on human and animal health. Anaplasma ovis infects sheep and goats in many regions of the world, and it can be diagnosed by different methods like Giemsa staining, PCR or competitive ELISA. In this study, a PCR based on the gene coding for major surface protein 4 (MSP-4) was used to examine field samples collected from sheep in different countries. Altogether, 1161 blood samples from Turkey (n = 830), Iraq (n = 195), Sudan (n = 96) and Portugal (n = 40) were examined, of which 31.4%, 66.6% 41.6% and 82.5%, respectively, were positive. This indicates high prevalence of A. ovis in the countries under investigation, and it can be assumed that the situation in other areas of the world might be similar. Thus, A. ovis should be considered as an important constraint of livestock production, and further efforts are needed to better understand the epidemiology and to implement suitable control measures.

Development and assessment of a latex agglutination test based on recombinant MSP5 to detect antibodies against Anaplasma marginale in cattle

The recombinant protein MSP5 has been established as an important antigen for serological diagnosis of Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). However, due to the high cost of specialized equipment, this technique is not accessible to all laboratories, especially in developing countries in areas where the disease is endemic. The present study describes the standardization of a latex agglutination test (LAT) to detect antibodies against A. marginale based on recombinant MSP5. Compared with indirect enzyme-linked immunosorbent assay (iELISA), the relative sensitivity and specificity of the LAT were 95.21% and 91.86% respectively, with an almost perfect agreement between tests (kappa index = 0.863). These results can be considered important for the serological diagnosis of A. marginale, as they indicate that the test represents a rapid and low cost alternative to ELISA.

Cross-protection between geographically distinct Anaplasma marginale isolates appears to be constrained by limited antibody responses

The rickettsia Anaplasma marginale causes the haemolytic disease bovine anaplasmosis, an economic problem in tropical and subtropical areas worldwide. The closely related but less pathogenic Anaplasma centrale is commonly used as a live vaccine to prevent anaplasmosis, but it can only be produced from infected blood. UFMG1 is a low pathogenic Brazilian strain of A. marginale, which has been shown to protect cattle against a high pathogenic Brazilian isolate. As UFMG1 can be grown in tick cells, the strain was proposed as a possible cell culture-derived vaccine. We have evaluated whether UFMG1 could protect cattle against a geographically distant heterologous strain, using A. centrale vaccination as a standard for comparison. Trial calves were infected with UFMG1, A. centrale or PBS. UFMG1-infected animals were more symptomatic than those infected with A. centrale, but none required treatment. All calves were then challenged with the Israeli A. marginale Gonen strain (one of the most prevalent strain in Israel). The A. centrale group had the mildest symptoms, while UFMG1 and control groups both had a more severe response. Nevertheless, the challenge did not cause life-threatening disease in any group. Animals infected with A. centrale had a significantly higher IgG response than UFMG1, when measured in an ELISA against initial bodies from their homologous strain or Gonen. The level of cross-reactivity of the response to initial infection correlated significantly with reduced symptoms after challenge. In conclusion, UFMG1 had limited effect in preventing disease by the geographically distant heterologous Gonen strain. While the low pathogenicity of the Gonen strain in this trial makes it impossible to conclusively state that UFMG1 would have given no protective effect against more serious disease, the comparatively low IgG response to UFMG1 suggests it would not have been as effective as A. centrale.

Molecular investigation and phylogeny of Anaplasma spp. in Mediterranean ruminants reveal the presence of neutrophil-tropic strains closely related to A. platys

Few data are available on the prevalence and molecular typing of species belonging to the genus Anaplasma in Mediterranean ruminants. In this study, PCR analysis and sequencing of both 16S rRNA and groEL genes were combined to investigate the presence, prevalence, and molecular traits of Anaplasma spp. in ruminants sampled on the Island of Sardinia, chosen as a subtropical representative area. The results demonstrate a high prevalence of Anaplasma spp. in ruminants, with animals infected by at least four of six Anaplasma species (Anaplasma marginale, A. bovis, A. ovis, and A. phagocytophilum). Moreover, ruminants host a number of neutrophil-tropic strains genetically closely related to the canine pathogen A. platys. The high Anaplasma spp. prevalence and the identification of as-yet-unclassified neutrophil-tropic strains raise concerns about the specificity of serological tests routinely used in ruminants and provide additional background for reconstructing the evolutionary history of species genetically related to A. phagocytophilum.

Serological cross-reactivity between Anaplasma marginale and an Ehrlichia species in naturally and experimentally infected cattle

Seroconversion and cross-reactivity in cattle infected with Anaplasma marginale or a recently described Ehrlichia species (BOV2010 from British Columbia, Canada) were investigated. The study used 76 samples from 20 animals, a commercially available competitive enzyme-linked immunosorbent assay (cELISA) for bovine anaplasmosis, and an indirect fluorescent antibody test (IFAT). Blood smear examination and/or polymerase chain reaction assay were performed to confirm or rule out the presence of Anaplasma or Ehrlichia. Samples comprised 3 groups. Group 1 consisted of 24 samples from 9 cattle naturally infected with Ehrlichia sp. BOV2010. Group 2 had 13 samples from 3 A. marginale-infected cattle from Manitoba, Canada. Group 3 had 39 samples, consisting of 26 from 5 calves experimentally infected with Ehrlichia sp. BOV2010, 10 from 2 calves experimentally infected with A. marginale from cattle (Manitoba) or bison (Saskatchewan), and 3 from an uninfected calf. All samples from cattle naturally or experimentally infected with Ehrlichia sp. BOV2010 or A. marginale were seropositive for A. marginale by both cELISA and IFAT, except 3 calves euthanized at 28 and 33 days post-inoculation (DPI) that did not seroconvert. Antibodies were detected in 2 experimental animals inoculated with Ehrlichia sp. BOV2010, as early as 28 and 33 DPI by the cELISA and IFAT, respectively, and by 42 DPI for both tests. The current study demonstrates that the specificity of the recombinant major surface protein 5 (MSP5) antigen is not restricted to Anaplasma spp., which reduces the utility of the test for serological diagnosis of bovine anaplasmosis in regions where Ehrlichia sp. BOV2010-infected cattle might exist.

Sheep experimentally infected with a human isolate of Anaplasma phagocytophilum serve as a host for infection of Ixodes scapularis ticks

Anaplasma phagocytophilum, first identified as a pathogen of ruminants in Europe, has more recently been recognized as an emerging tick-borne pathogen of humans in the U.S. and Europe. A. phagocytophilum is transmitted by Ixodes spp., but the tick developmental cycle and pathogen/vector interactions have not been fully described. In this research, we report on the experimental infection of sheep with the human NY-18 isolate of A. phagocytophilum which then served as a host for infection of I. scapularis nymphs and adults. A. phagocytophilum was propagated in the human promyelocytic cell line, HL-60, and the infected cell cultures were then used to infect sheep by intravenous inoculation. Infections in sheep were confirmed by PCR and an Anaplasma-competitive ELISA. Clinical signs were not apparent in any of the infected sheep, and only limited hematologic and mild serum biochemical abnormalities were identified. While A. phagocytophilum morulae were rarely seen in neutrophils, blood film evaluation revealed prominent large granular lymphocytes, occasional plasma cells, and rare macrophages. Upon necropsy, gross lesions were restricted to the lymphoid system. Mild splenomegaly and lymphadenomegaly with microscopic evidence of lymphoid hyperplasia was observed in all infected sheep. Female I. scapularis that were allowed to feed and acquire infection on each of the 3 experimentally infected sheep became infected with A. phagocytophilum as determined by PCR of guts (80-87%) and salivary glands (67-100%). Female I. scapularis that acquired infection as nymphs on an experimentally infected sheep transmitted A. phagocytophilum to a susceptible sheep, thus confirming transstadial transmission. Sheep proved to be a good host for the production of I. scapularis infected with this human isolate of A. phagocytophilum, which can be used as a model for future studies of the tick/pathogen interface.

Prevalence and molecular characterization of Anaplasmataceae agents in free-ranging Brazilian marsh deer (Blastocerus dichotomus)

Anaplasmataceae organisms comprise a group of obligate intracellular gram-negative, tick-borne bacteria that can infect both animals and humans. In the present work we investigate the presence of Ehrlichia, Anaplasma, and Neorickettsia species in blood samples from Brazilian marsh deer (Blastocerus dichotomus), using both molecular and serologic techniques. Blood was collected from 143 deer captured along floodplains of the Paraná River, near the Porto Primavera hydroelectric power plant. Before and after flooding, marsh deer were captured for a wide range research program under the financial support of São Paulo State Energy Company (CESP), between 1998 and 2001. Samples were divided into four groups according to time and location of capture and named MS01 (n=99), MS02 (n=18) (Mato Grosso do Sul, before and after flooding, respectively), PX (n=9; Peixe River, after flooding), and AGUA (n=17; Aguapeí River, after flooding). The seroprevalences for Ehrlichia chaffeensis and Anaplasma phagocytophilum were 76.76% and 20.2% in MS01, 88.88% and 5.55% in MS02, 88.88% and 22.22% in PX, and 94.12% and 5.88% in AGUA, respectively. Sixty-one animals (42.65% of the total population) were PCR-positive for E. chaffeensis PCR (100.0% identity based on 16S rRNA, dsb, and groESL genes). Seventy deer (48.95% of the total population) were PCR-positive for Anaplasma spp. (99.0% of identity with A. platys, and in the same clade as A. phagocytophilum, A. bovis, and A. platys based on 16S rRNA phylogenetic analysis). Our results demonstrate that Brazilian marsh deer are exposed to E. chaffeensis and Anaplasma spp. and may act as reservoirs for these rickettsial agents, playing a role in disease transmission to humans and other animals.

Molecular study of free-ranging mule deer and white-tailed deer from British Columbia, Canada, for evidence of Anaplasma spp. and Ehrlichia spp

Twenty-three free-ranging white-tailed deer (WTD; Odocoileus virginianus) and six mule deer (MD; Odocoileus hemionus) from south-central British Columbia, Canada, were tested for Anaplasma marginale by msp5 gene-specific PCR and Ehrlichia spp. by 16S rRNA or citrate synthase (gltA) gene-specific PCR, as well as by PCR with universal 16S rRNA primers detecting a wide range of bacteria. No deer tested positive for A. marginale. Amplification with universal 16S rRNA primers followed by sequencing of cloned fragments detected an Anaplasma sp. in one of 23 (4.3%) WTD and six of six (100%) MD and Bartonella sp. in four of 23 (17.4%) WTD. The Anaplasma sp. was genetically distinct from A. marginale and all other recognized members of the genus. Four of six (66.7%) MD and 0 of 23 (0%) WTD were Ehrlichia positive by PCR with primers for 16S rRNA and gltA genes. The sequences of gltA PCR fragments were identical to each other and to the respective region of the gltA gene of an Ehrlichia sp. which we detected previously in naturally infected cattle from the same area, suggesting the possibility of biological transmission of this rickettsia between cattle and wild cervids. Antibodies reactive with the MSP5 protein of A. marginale were detected using a competitive enzyme-linked immunosorbent assay in two of six (33.3%) MD, but not in WTD. The two seropositive MD were PCR positive for both the Anaplasma sp. and Ehrlichia sp. detected in this study, suggesting a reaction of antibodies against one or both of these rickettsias with the MSP5 antigen.

Real time polymerase chain reaction to diagnose Anaplasma marginale in cattle and deer (Ozotoceros bezoarticus leucogaster) of the Brazilian Pantanal

Epizootiological study of Anaplasma marginale in regions that contain various reservoir hosts, co-existence of rickettsia pathogens, and common vectors is a complicated task. To achieve diagnosis of this rickettsia in cattle and campeiro deer of Brazilian Pantanal, a comparison was made between a real time polymerase chain reaction (RT-PCR) with intercalating Sybr Green fluorochrome and primers based on msp5 gene of A. marginale; a conventional PCR (C-PCR); and parasitological examination using thin blood smear stained with Giemsa-MayGrunwald. Both PCRs showed good performance in the diagnosis of A. marginale in cattle, and were superior to the parasitological exam. The RT-PCR detected seven positive campeiro deer (16.3%). This rate was significantly higher compared to C-PCR, which identified one animal as positive (2.3%), and also compared to parasitological diagnosis, which did not find any positive animals. The dissociation temperature average of positive reactions in cattle (81.72 °C ± 0.20) was identical to dissociation temperature found in the cervids (81.72 °C ± 0.12), suggesting that both animal species were infected with A. marginale. We concluded that RT-PCR can be used for A. marginale diagnosis and in epizootiological studies of cattle and cervids; in spite of the small number of campeiro deer samples, the results indicated that this wildlife species has importance in the Anaplasma epizootiology in the Brazilian Pantanal.

Novel genotypes of Anaplasma bovis, "Candidatus Midichloria" sp. and Ignatzschineria sp. in the Rocky Mountain wood tick, Dermacentor andersoni

Bovine anaplasmosis, caused by Anaplasma marginale, is a vector-borne disease that is enzootic in many parts of the USA. Although Dermacentor andersoni, a major vector of A. marginale, occurs in Canada, the Canadian cattle herds are currently considered free of bovine anaplasmosis. There have been two outbreaks of the disease in the province of Saskatchewan, but these have been linked to the importation of infected animals. However, the distribution of bovine anaplasmosis may alter with range expansion of the vectors. The aim of the present study was to use molecular techniques to determine if Anaplasma were present in D. andersoni at a locality near its northeastern distributional limit in Saskatchewan. Nested PCR analyses of the bacterial 16S rRNA gene were conducted on the total genomic DNA of 105 individual ticks. Single strand conformation polymorphism analysis and DNA sequencing of the 11 PCR-positive amplicons revealed the presence of three species of bacteria, none of which have been previously reported in D. andersoni. Although no ticks were infected with A. marginale, a novel genotype of A. bovis was detected in eight individuals. This discovery represents the first report of A. bovis in Canada. The potential implications of this finding with respect to animal health and anaplasmosis surveillance in Canada are discussed. The other two bacterial species detected were genetically similar to "Candidatus Midichloria mitochondrii" and Ignatzschineria larvae, the latter of which has been associated with human disease in Europe. Further investigations are needed to determine the prevalence, reservoir hosts, and pathogenicity of the Canadian genotype of A. bovis.

Comparison of iatrogenic transmission of Anaplasma marginale in Holstein steers via needle and needle-free injection techniques

OBJECTIVE

To compare iatrogenic transmission of Anaplasma marginale during sham vaccination between needle and needle-free injection techniques.

ANIMALS

26 Holstein steers confirmed negative for anaplasmosis by use of a competitive ELISA (cELISA) and an A marginale-specific reverse transcription (RT)-PCR assay.

PROCEDURES

An isolate of A marginale was propagated to a circulating parasitemia of 2.0% in a splenectomized steer. Sham vaccination was performed in the left cervical muscles of the splenectomized parasitemic steer with a hypodermic needle fitted to a multiple-dose syringe. The same needle and syringe were used to sham vaccinate a naïve steer. This 2-step procedure was repeated until 10 naïve steers (group ND) were injected. Similarly, sham vaccination of the left cervical muscles of the splenectomized parasitemic steer and another group of 10 naïve steers (group NF) was performed by use of a needle-free injection system. Five control steers were not injected. Disease status was evaluated twice weekly for 61 days by use of light microscopy, a cELISA, and an A marginale-specific RT-PCR assay.

RESULTS

Iatrogenic transmission was detected in 6 of 10 steers in group ND. Disease status did not change in the NF or control steers. Sensitivity of light microscopy, cELISA, and RT-PCR assay was 100% on days 41, 41, and 20 after sham vaccination, respectively; however, only cELISA and RT-PCR assay sustained a sensitivity of 100% thereafter.

CONCLUSIONS AND CLINICAL RELEVANCE

Needle-free injection was superior to needle injection for the control of iatrogenic transmission of A marginale.

Molecular survey and genetic characterization of tick-borne pathogens in dogs in metropolitan Recife (north-eastern Brazil)

To identify DNA of the main tick-borne pathogens in dogs from Recife (Brazil), polymerase chain reactions were carried out on blood samples of dogs treated at the Veterinary Hospital of the Universidade Federal Rural de Pernambuco from March 2007 to June 2008. The detection of DNA was performed using specific primers. Amplicons were analyzed through electrophoresis and sequencing. A phylogenetic tree was constructed using the UPGMA method, revealing that the sequences were closely related to those of strains from other geographic regions. Among the 205 blood samples analyzed, 48.78% was positive for Anaplasma platys; 38.04% was positive for Ehrlichia canis; 7.31% was positive for Babesia canis vogeli; and 0.49% was positive for Hepatozoon canis and Mycoplasma haemocanis. Coinfection of two or three pathogens was found in 23.9% (49/205) of the dogs. The subspecies B. canis vogeli was identified. Infection by H. canis and M. haemocanis is reported for the first time in dogs in the state of Pernambuco (Brazil). The data indicate that the main tick-borne pathogens in dogs in this region are E. canis and/or A. platys, followed by B. canis vogeli.

Detection of Anaplasma marginale and A. phagocytophilum in bovine peripheral blood samples by duplex real-time reverse transcriptase PCR assay

Insufficient diagnostic sensitivity and specificity coupled with the potential for cross-reactivity among closely related Anaplasma species has made the accurate determination of infection status problematic. A method for the development of simplex and duplex real-time quantitative reverse transcriptase PCR (qRT-PCR) assays for the detection of A. marginale and A. phagocytophilum 16S rRNA in plasma-free bovine peripheral blood samples is described. The duplex assay was able to detect as few as 100 copies of 16S rRNA of both A. marginale and A. phagocytophilum in the same reaction. The ratio of 16S rRNA to 16S DNA copies for A. marginale was determined to be 117.9:1 (95% confidence interval [95% CI], 100.7:1, 135.2:1). Therefore, the detection limit is the minimum infective unit of one A. marginale bacterium. The duplex assay detected nonequivalent molar ratios as high as 100-fold. Additionally, the duplex assay and a competitive enzyme-linked immunosorbent assay (cELISA) were used to screen 237 samples collected from herds in which anaplasmosis was endemic. When the cELISA was evaluated by the results of the qRT-PCR, its sensitivity and specificity for the detection of A. marginale infection were found to be 65.2% (95% CI, 55.3%, 75.1%) and 97.3% (95% CI, 94.7%, 99.9%), respectively. A. phagocytophilum infection was not detected in the samples analyzed. One- and two-way receiver operator characteristic curves were constructed in order to recommend the optimum negative cutoff value for the cELISA. Percentages of inhibition of 20 and 15.3% were recommended for the one- and two-way curves, respectively. In conclusion, the duplex real-time qRT-PCR assay is a highly sensitive and specific diagnostic tool for the accurate and precise detection of A. marginale and A. phagocytophilum infections in cattle.

Molecular and serological evidence of Anaplasma phagocytophilum infection of farm animals in the Black Sea Region of Turkey

This study was designed to determine the presence and the prevalence of Anaplasma phagocytophilum infection in sheep and cattle in the Middle and Eastern Black Sea Regions of Turkey in which the potential vector, Ixodes ricinus, is widespread. Blood samples were collected from 720 sheep and 720 cattle from 6 provinces of the region, and used for detecting antibodies to A. phagocytophilum by indirect immunofluorescent antibody test (IFAT) and specific nucleic acids by a nested polymerase chain reaction (PCR). Blood smears were also prepared and examined microscopically for the presence of A. phagocytophilum-like organisms in polymorphonuclear cells. Of the animals examined, antibodies were detected in 110 (15.27%) cattle and 107 (14.86%) sheep and A. phagocytophilum-like organisms were detected in the blood of 73 (10.13%) cattle and 71 (9.86%) sheep. In addition, specific DNA was detected in the blood of 27 (14.75%) cattle and 22 (12.35%) sheep. The results obtained constitute the first molecular and serological evidence of A. phagocytophilum infection in sheep and cattle in the Black Sea Region of Turkey.

Detecção de anticorpos para Anaplasma sp. em pequenos ruminantes no semi-árido do estado de Pernambuco, Brasil

Neste trabalho é descrita a detecção de anticorpos para Anaplasma sp. em caprinos e ovinos da região do semi-árido do Estado de Pernambuco, Brasil, utilizando-se um ensaio de imunoadsorção enzimática baseado em MSP5 recombinante de Anaplasma marginale. Foram analisados soros de 243 caprinos e 68 ovinos provenientes do município de Ibimirim, e observadas freqüências de anticorpos de 11,93% (29/243) e 16,17% (11/68) para caprinos e ovinos, respectivamente. A importância epidemiológica dos achados foi discutida.