Seroprevalence of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in Danish horses

Seroprevalence of IgG Antibodies Against Borrelia burgdorferi Sensu Lato, Anaplasma phagocytophilum, and Tick-Borne Encephalitis (TBE) Virus in Horses in Southern Norway

Ixodes ricinus ticks play a crucial role as carriers of diseases, transmitting pathogens to vertebrate hosts, including horses. This study aimed to investigate the seroprevalence of IgG antibodies against Borrelia burgdorferi sensu lato (s. l.), Anaplasma phagocytophilum, and tick-borne encephalitis virus (TBE-virus) in equine sera collected in southern Norway. In total, sera from 331 horses stabled in four counties (Agder, Vestfold and Telemark, Vestland, and Viken) were analyzed by immunoblot. In total, 66% of the horses were IgG-seropositive for antibodies against one or multiple tick-borne pathogens. The highest seroprevalence was detected against B. burgdorferi s. l. (47%), followed by A. phagocytophilum (34%) and TBE-virus (10%). A significant difference between the counties regarding IgG antibodies against A. phagocytophilum was found, with the highest seroprevalence in horses stabled in the coastal areas of Agder and Vestland. In conclusion, the study demonstrates that horses in southern Norway are at high risk of contracting tick-borne infections.

[Equine granulocytic anaplasmosis (EGA): Case description and overview of the epidemiological situation with focus on Germany]

Equine granulocytic anaplasmosis (EGA) is a tick-borne disease caused by Anaplasma (A.) phagocytophilum. In Central, Northern, Western, and Eastern Europe, ticks of the Ixodes (I.) ricinus/I. persulcatus complex, in Germany mainly I. ricinus, are considered as vectors. Ixodes ricinus ticks show peaks of activity during the spring and summer months, particularly April to July. Changing climatic conditions, however, have meanwhile led to a year-round risk of tick exposure and thus infections with A. phagocytophilum. The presented case report underlines the seasonal peak phase of the infection risk in that the presentation of the horse to the veterinarian occurred in June. Additionally, clinical signs - including fever - are mostly unspecific and thrombocytopenia represents the most significant hematological abnormality. Direct and indirect detection methods are available for the diagnosis of an infection or contact with the pathogen. A positive PCR confirms an acute infection, as in the presented case, while positive antibody levels indicate contact with the pathogen in the (recent) past. Additionally, inclusion bodies, so called morulae, may be detected rapidly and inexpensively in smears derived from the peripheral blood and are predominantly found in neutrophilic granulocytes, less frequently in eosinophilic granulocytes. However, microscopy has a lower sensitivity compared to PCR-testing. In the presented case, morulae could not be detected in EDTA blood despite positive PCR. Antibiotics with intracellular activity, such as oxytetracycline and/or doxycycline are the treatment of choice and, as in the described case, often result in rapid clinical improvement in horses suffering from EGA. The elimination of the pathogen should be confirmed by PCR-testing 5-8 days after the completion of the antibiotic therapy. Whether and how long antibodies against A. phagocytophilum could possibly be protective against reinfection remains unknown. In humans, A. phagocytophilum is classified as an emerging pathogen of increasing clinical importance in the northern hemisphere.

Evidence of Horse Exposure to Anaplasma phagocytophilum, Borrelia burgdorferi, and Leishmania infantum in Greece through the Detection of IgG Antibodies in Serum and in an Alternative Diagnostic Sample-The Saliva

Among the various zoonotic pathogens that infect horses, Anaplasma phagocytophilum, Borrelia spp. and Leishmania spp. have gained scientific interest, and relevant molecular and serological studies in horses have been conducted worldwide. Moreover, human and veterinary medicine have extensively applied alternatives to serum diagnostic samples-such as saliva-for detecting pathogens or antibodies. In this study, we investigated the exposure of horses in Greece to A. phagocytophilum, B. burgdorferi, and L. infantum, and we assessed the diagnostic accuracy of saliva compared to serum in detecting IgG antibodies against the abovementioned pathogens. Paired saliva and serum samples were collected from 317 horses from different regions in Greece. The paired samples were examined using the indirect fluorescent antibody test (IFAT) for detecting IgG antibodies against A. phagocytophilum, B. burgdorferi, and L. infantum. Sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were determined to assess the validity of saliva as an alternative to serum. The receiver operating characteristic (ROC) curve revealed that the optimal cut-off value for detecting antibodies against all the examined pathogens in saliva was 1/10. Higher seropositivity rates were found for B. burgdorferi (15.14%) and A. phagocytophilum (14.19%) compared to L. infantum (1.26%). The detection of IgG antibodies using IFAT in saliva samples had a good test performance compared to serum. The two sample types had a substantial to almost perfect agreement. Although the sensitivity was moderate (70.83-75.56%) in all cases, the specificity was almost perfect to perfect (99.63-100%). This study provides the first evidence that horses in Greece are exposed to A. phagocytophilum and B. burgdorferi and confirms that the seroprevalence of L. infantum in horses in Greece remains low. Our findings suggest that saliva sampling coupled with IFAT could be successfully applied for detecting IgG antibodies against these important zoonotic pathogens in large-scale epidemiological studies in horses, at the population level, as an alternative to serum.

Antibodies against Borrelia burgdorferi Sensu Lato in Clinically Healthy and Sick Horses: First Report from the Czech Republic

Lyme disease, caused by some strains of bacterial spirochetes Borrelia burgdorferi sensu lato (Bbsl), affects humans but also domestic animals including horses. The primary pathogens in horses in Europe are B. afzelii, B. garinii and B. burgdorferi sensu stricto. To our knowledge, there are no data available on the seropositivity of B. burgdorferi s.l. in horses from the Czech Republic. In this country, horses are mainly used for sport, breeding, and recreational riding in areas where vectors of B. burgdorferi s.l. are present, which is why they are frequently at risk of infection. The aim of the study was to detect anti-borrelia IgM and IgG antibodies in clinically healthy and sick horses from the Czech Republic and to evaluate the risk factors of infection. In total, sera of 262 horses (247 clinically healthy horses and 15 horses hospitalized due to symptoms of encephalitis/meningoencephalitis) were examined by an indirect sandwich enzyme-linked immunosorbent assay. Positivity of B. burgdorferi was 27% (66/247) in clinically healthy horses (21% IgM, 7% IgG and 3% IgM + IgG antibodies) and 20% (3/15) in horses with clinical signs (20% IgM, 7% IgG and 7% IgM + IgG). In the clinically healthy horses, positivity statistically differed (p ≤ 0.05) only in Pony and Warmblood breeds, being the most affected at 32% and 30%, respectively, while other characteristics (sex, age, usage and localities) had no effect on positivity. This is the first survey of antibodies to B. burgdorferi s.l. in Czech horses showing that horses are exposed to ticks infected with B. burgdorferi s.l. This should be taken into account when making differential diagnoses in patients with non-specific symptoms to start with adequate therapy.

Seroexposure to Zoonotic Anaplasma and Borrelia in Dogs and Horses That Are in Contact with Vulnerable People in Italy

Equine and canine anaplasmosis and borreliosis are major tick-borne zoonotic diseases caused by Anaplasma phagocytophilum and various species of Borrelia (the most important being Borrelia burgdorferi s.l.), respectively. This study evaluated the seroexposure to Anaplasma and Borrelia in dogs and horses used in Animal-Assisted Interventions or living in contact with children, elderly people or immunocompromised persons. A total of 150 horses and 150 dogs living in Italy were equally divided into clinically healthy animals and animals with at least one clinical sign compatible with borreliosis and/or anaplasmosis (present at clinical examination or reported in the medical history). Serum samples were tested with ELISA and immunoblot for the presence of antibodies against A. phagocytophilum and B. burgdorferi s.l., and the association between seropositivity and possible risk factors was analyzed using multivariate and univariate tests. Overall, 13 dogs (8.7%) and 19 horses (12.7%) were positive for at least one of the two pathogens. In addition, 1 dog (0.7%) and 12 horses (8%) were positive for antibodies against A. phagocytophilum, while 12 dogs (8.0%) and 10 horses (6.7%) had antibodies against B. burgdorferi s.l. Tick infestation in the medical history of the dogs was significantly associated with seropositivity to at least one pathogen (p = 0.027; OR 7.398). These results indicate that, in Italy, ticks infected with A. phagocytophilum and/or B. burgdorferi circulate in places where horses and dogs are in contact with people at risk of developing severe diseases. Awareness should be increased, and adequate control plans need to be developed to protect human and animal health, especially where vulnerable, at-risk individuals are concerned.

Immune and Inflammatory Response of Donkeys (Equus asinus) Tested Positive to Tick-borne Pathogens

Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity and mortality and, in some cases, to their zoonotic relevance. Understanding the host immune/inflammatory response to the pathogens is crucial to develop effective methods of diagnosis, control and treatment. This study aimed to evaluate red blood cells (RBC), hematocrit (Hct), hemoglobin concentration (Hb), mean cell volume (MCV), mean cell hemoglobin content (MCH), mean cell hemoglobin (MCHC), platelets (PLT), white blood cells (WBC), leukocytes populations, and serum protein pattern of Sardinian donkeys scored positive to tick-borne pathogens. Thirty donkeys were dived in five groups, six subjects each: Group 1, tested negative to pathogens (control group); Group 2, donkeys infected by Theileria equi; Group 3, donkeys infected by Ehrlichia equi; Group 4, donkeys infected by Rickettsia Rickettsii; Group 5, donkeys co-infected by T. equi, E. equi and R. Rickettsii. From donkeys blood samples were collected and haematological and serum protein profiles were assessed. One-way ANOVA showed lower red blood cells, haemoglobin, platelets, lymphocytes and neutrophils values, and higher eosinophils, basophils, serum total proteins, α2-, β- and γ- globulins values in donkeys infected by one or more pathogens compared to control group (P < .05). The study highlighted an immune and inflammatory response of donkeys positive to E. equi, T. equi, and R. Rickettsii and represents a starting point for further investigations in the field to fill the gaps currently existing on the complex interwoven relationship between the pathogen and host immune and inflammatory response in equids.

Seroprevalence of Tick-Borne Infections in Horses from Northern Italy

Simple Summary

Equine vector-borne diseases, which include equine granulocytic anaplasmosis (EGA) and equine piroplasmosis (EP), are caused by several pathogens transmitted to horses by ticks. Considering the spread of equine vector-borne diseases in Italy and worldwide, a study was planned to investigate the seroprevalence of Anaplasma phagocytophilum and the other two selected pathogens, Theileria equi and Babesia caballi, in northern Italy. Data obtained from the present study demonstrated a high seroprevalence for all the three surveyed tick-borne pathogens and emphasized the importance of establishing control programs with the adoption of certain practices, including tick control, correct horses management, serological screening, regular usage of long-lasting acaricides and proper treatment of positive and clinically infected animals.

Abstract

Tick-borne diseases in horses are considered an emergent problem worldwide; the geographical redistribution of ticks, due to climatic and ecological changes, and the movements of infected horses between different nations play important roles in the spread of tick-borne diseases affecting these hosts. In this study, a survey was planned to estimate the seroprevalence of the Gram-negative bacterium Anaplasma phagocytophilum and the piroplasmid protozoa Babesia caballi and Theileria equi in Italian horses, as well as to evaluate possible risk factors associated with seropositive cases. Serum samples from 261 horses reared in northern Italy were collected and analyzed by indirect immunofluorescence antibody test for the detection of A. phagocytophilum-, B. caballi- and T. equi-specific antibodies. The overall seroprevalence to at least one of the investigated pathogens was 51%; sixty-one horses were seropositive to A. phagocytophilum (23.4%), forty-nine to B. caballi and the same number to T. equi (18.8% each). Seropositivity for more than one of the investigated agents was detected in thirty-two horses and the most common co-infection was observed between B. caballi and T. equi (5.7%). A significant risk factor for all the three pathogens was the elevation above sea level; indeed, the risk of infection was higher with an increase and decrease in elevation for A. phagocytophilum and for B. caballi and T. equi, respectively. Tick control in horses is strongly recommended considering the high seroprevalence values of transmitted pathogens.

Serological and Molecular Detection of Anaplasma spp. in Blood From Healthy Horses: A Preliminary Study of Horses in East Texas

Anaplasmosis is a disease caused by the bacterium Anaplasma phagocytophilum, which is spread by infected ticks. In horses, A. phagocytophilum generally causes transient infection characterized by fever, lethargy, inappetence, ventral edema, petechiae, icterus, ataxia, recumbency, muscle stiffness, and, in severe cases, death. Following natural infection, horses retain antibodies for approximately 2 years, which can be detected through an immunofluorescence antibody assay. Current infections are determined through PCR assay of white blood cell DNA. For this study, whole blood was collected from apparently healthy horses located in East Texas (n = 70), west Texas (n = 3), New York (n = 49), and New Jersey (n = 11) for the determination of serum antibodies and PCR testing of bacterial DNA. Of the 133 horses, 24 tested positive for DNA presence of A. phagocytophilum, and 107 tested positive for serum antibodies. Of the 24 horses testing positive for A. phagocytophilum, 16 were positive for serum antibody presence and 8 were negative. Twenty of the msp2 positive horses were located in East Texas and 4 resided in New York. For serum antibodies, 100% of New York and New Jersey horses tested positive, while only 66% of Texas horses tested positive. This study provides evidence that a large number of horses are exposed to A. phagocytophilum and that this bacterium is present in East Texas. No Texas horse owners reported treatment for anaplasmosis, and the currently infected horses were not demonstrating signs of illness at the time of sample collection. Further research to understand the differences in disease severity amongst equine populations is warranted.

Frequency and factors associated of potential zoonotic pathogens (Borrelia spp., Rickettsia spp., Leishmania spp., and Anaplasma phagocytophilum) in equids in the state of Bahia, Brazil

BACKGROUND

Currently, various zoonotic diseases are classified as emerging or reemerging. Because equids have a direct relationship with various vectors, they are possibly more frequently exposed to zoonotic agents than are humans. The undeniable importance of diseases such as human granulocytic anaplasmosis, spotted fever, and leishmaniasis for both public and animal health, as well as the possibility of equids acting as sources, reservoirs, or even sentinels for these pathogens, justifies the detection of their frequency and factors associated with infection in equids from northeastern Brazil.

METHODS

Blood samples were collected from 569 equids (528 horses, 33 donkeys, and 8 mules), 516 from a rural area and 53 from an urban area. Pathogen detection was carried out as follows: Borrelia spp. and Rickettsia spp., serological analysis; Leishmania spp., serological analysis and polymerase chain reaction (PCR); Anaplasma phagocytophilum, PCR. Determination of associated factors was carried out through generalized linear models.

RESULTS

The frequencies of positivity for the pathogens observed in equids were as follows: Borrelia spp., 13.9% (79/569); Leishmania spp., 3.5% (20/569); Rickettsia spp. 33.4% (190/569). Regarding factors associated with infection, male sex was associated with protection against Borrelia spp.; donkeys and mules were associated with protection against Rickettsia spp., while a younger age was a risk factor. The infection of A. phagocytophilum was not detected in the sampled population. Co-infection was detected in 5.1% (29/569) of the animals.

CONCLUSIONS

Most of the studied pathogenic agents are present in the prospected area, indicating a possible risk for both human and animal health. This demonstrates that equids can be considered important sentinels in the assessment of pathogens with zoonotic potential in the region.

Molecular surveillance of tick-borne diseases affecting horses in Poland-Own observations

The purpose of the study was to carry out the molecular surveillance of piroplasmosis, granulocytic anaplasmosis and lyme borreliosis in horses which originated from Poland and exhibited symptoms raising the suspicion of the aforementioned disease units. The presence of Theileria equi genetic material was detected in 37 out of 512 examined horses (7.2%), and Anaplasma phagocytophilum in 9 (1.8%). The DNA of Borrelia burgdorferi was found in 11 out of 204 examined horses (5.4%). The above-cited results indicate that the problem of tick-borne diseases affecting horses in Poland is not as significant as in other parts of Europe, however they have to be considered in differential diagnosis of the diseases with lethargy, fever, anaemia and thrombocytopenia.

Serological Evidence of Natural Exposure to Tick-Borne Pathogens in Horses, Romania

The purpose of this study was to investigate the seroprevalence of selected tick-borne-pathogens (TBPs) among Romanian horses. For this, a total of 223 animals originating from north, central, and southeast Romania, including horses from stud farms (n = 118) and working horses (n = 105), were tested using a commercial rapid ELISA-based test. Overall, 10.3% (95% confidence interval (CI): 6.7-15.1%) of the tested horses were seropositive for antibodies (Ab) against Anaplasma phagocytophilum. Additionally, 18.8% (95% CI: 13.9-24.6%) and 0.5% (95% CI: 0.01-2.5%) of horses were seropositive for Ab against Borrelia burgdorferi sensu lato and Ehrlichia spp., respectively. Among the tested horses, 3.1% were seroreactive to two or three pathogens. These findings show the natural exposure of Romanian horses to zoonotic tick-borne pathogens and emphasize the need for further studies to better understand the epidemiology of equine tick-borne diseases in Romania.

Equine Granulocytic Anaplasmosis, A Neglected Disease: Risk Factors Associated with Prevalence of Antibodies in Equines

Background:

Anaplasma phagocytophilum, a tick-borne bacterium that causes granulocytic anaplasmosis, is a neglected pathogen in Brazil, and is diagnosed in several species of domestic and wild animals as well as in humans.

Objective:

This study aimed to investigate the prevalence of anti-A. phagocytophilum antibodies in Equidae from the state of Rio de Janeiro and to identify possible risk factors for infection.

Materials and Methods:

A total of 612 blood samples were collected from horses from 15 municipalities within the state. Moreover, an epidemiological questionnaire was administered to evaluate aspects related to seroreaction, taking into account the spatial distribution (properties, municipalities, and mesoregions), management practices, signs of disease, and the individual state of the animals. For the diagnosis, indirect immunofluorescence was performed.

Results:

In the present study, 124 (20.26%), out of a total of 612, animals with anti-A. phagocytophilum IgG antibodies at titers of 1:80 were detected. Multivariate logistic regression analysis showed that the presence of the infection at the property (P <0.0001) and the origin (P = 0.0095) of the horse were the true risk factors for infection in the state of Rio de Janeiro.

Conclusion:

This allows to infer that the bacterium is distributed in all mesoregions of the state of Rio de Janeiro and that animals from other states can introduce the infection and make a property a focus of disease; it can also be inferred that these properties are important in the maintenance of the disease and the permanence of bacteria circulating in horses. It is also noteworthy that this was the first identification of mules as hosts of A. phagocytophilum infection.

Modelling the probability and impact of false-positive serology for Borrelia burgdorferi sensu lato: A case study

Background

Serological screening tests for Lyme borreliosis have poor specificity, with potential for misdiagnosis and unnecessary antimicrobial treatment.

Objectives

To evaluate the impact of Lyme borreliosis seroprevalence and serologic test characteristics on the probability of obtaining a false‐positive result and impact on antimicrobial use.

Study design

Cross‐sectional serological survey and modelling.

Methods

Sera from 303 horses in southern Belgium were analysed by enzyme‐linked immunosorbent assay (ELISA). Apparent seroprevalence was derived from serological data and a Bayesian estimate of true seroprevalence was computed. These were a starting point to model the impact of test and population characteristics on the probability of obtaining false‐positive results and consequently unnecessary treatments and complications.

Results

Apparent and true seroprevalence were 22% (95% CI 18%‐27%) and 11% (credible interval with 95% probability 0.6%‐21%) respectively. We estimate that two‐thirds of positive samples are false positive in southern Belgium, with one in five of tested horses potentially misdiagnosed as infected. Around 5% of antimicrobial use in equine veterinary practice in Belgium may be attributable to treatment of a false‐positive result.

Main limitations

There was uncertainty regarding the ELISA's sensitivity and specificity.

Conclusions

This study highlights the importance of appreciating the poor diagnostic value of ELISA screening for Lyme borreliosis as demonstrated by this case study of seroprevalence in southern Belgium where we demonstrate that a nontrivial number of horses is estimated to receive unwarranted treatment due to poor appreciation of screening test characteristics by practitioners, contributing substantially to unnecessary use of antimicrobials.

Seroprevalence of Anaplasma phagocytophilum, Ehrlichia spp. and Borrelia burgdorferi infections in horses: first report from Northern Bulgaria - Short communication

Lyme borreliosis, granulocytic anaplasmosis and monocytic ehrlichiosis are well studied in humans and dogs. In horses, these diseases are not widely investigated and limited information is available about their occurrence. The purpose of this study was to present the first ELISA-based report on the seroprevalence of Anaplasma phagocytophilum, Ehrlichia spp. and Borrelia burgdorferi in horses from Northern Bulgaria. A total of 192 horses were investigated from three regions in Northern Bulgaria (Northwestern, North-Central and Northeastern Bulgaria). All equine sera were tested for A. phagocytophilum, Ehrlichia spp. and B. burgdorferi antibodies by a commercial rapid ELISA test. Antibodies against A. phagocytophilum were found in all the three regions at a mean frequency of 12% (23/192), ranging from 9.38 to 15.63% by region. Antibodies against Ehrlichia spp. were found in horses from one region (Northeastern) at a rate of 0.5% (1/192). Anti-B. burgdorferi antibodies were detected in all the three regions with a mean frequency of 15.1% (29/192), ranging from 14.06 to 17.19% by region. A co-exposure to A. phagocytophilum and B. burgdorferi was observed in 6.3% of the cases (12/192). This is the first report on the natural exposure of horses to these bacteria (A. phagocytophilum, Ehrlichia spp. and B. burgdorferi) in Northern Bulgaria.

Molecular evidence of Anaplasma phagocytophilum and Theileria equi coinfection in horses from Rio de Janeiro, Brazil

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Molecular evidence of coinfection with A. phagocytophilum and T. equi in horses in Brazil was confirmed for the first time by the detection of DNA from both agents.

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EGA should be included in differential diagnosis of tick-borne diseases in horses.

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Different clinical manifestations in horses may be due to coinfection.

The present study aims to determine the frequencies of Theileria equi and Anaplasma phagocytophilum antibodies among horses from the state of Rio de Janeiro, Brazil, and to detect the presence of DNA of these pathogens through molecular methods. A total of 98 serum samples of horses from the municipality of Seropedica were tested by indirect immunofluorescence antibody (IFA) to detect anti-A. phagocytophilum and anti-T. equi IgG antibodies. In addition, quantitative real-time PCR (qPCR) was used to detect these pathogens in the DNA extracted from the whole blood and buffy coat of horses. Bivariate analysis and odds ratio were performed to verify the possible association between positivity and characteristics related to the horses. As evaluated by IFA and qPCR, the frequency of animals that tested positive for T. equi was 89.8% (n = 88/98) and 91.8% (n = 90/98), whereas A. phagocytophilum was 17.4% (n = 17/98) and 1.0% (n = 1/98), respectively. Serological evidence of exposure to A. phagocytophilum and T. equi was observed in 16.3% (n = 16/98) of the horses; however, exposure was confirmed by qPCR in only 1.0% (n = 1/98). No statistical association was found in the bivariate and odds ratio analysis. This is the first study reporting the molecular detection of A. phagocytophilum DNA in horses from the state of Rio de Janeiro, and also the coinfection of A. phagocytophilum and T. equi in a horse from Brazil confirmed by molecular methods. Equine granulocytic anaplasmosis is circulating in Brazilian horses, together with T. equi, and should be included in the differential diagnosis of tick-borne diseases.

Serological Evidence of Borrelia burgdorferi, Anaplasma phagocytophilum and Ehrlichia Spp. Infections in Horses from Southeastern Bulgaria

Lyme Borreliosis and granulocytic anaplasmosis are less extensively studied in horses than in dogs and humans. Equine ehrlichiosis is not known in Europe and is in the initial stage of investigation in South, Central, and North America. The aim of this study was to determine the seroprevalence of these infections in Bulgaria. A total of 155 horses were investigated from five regions in Southeastern Bulgaria. Horses were tested for Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia spp. antibodies by a commercial rapid ELISA test. B. burgdorferi and A. phagocytophilum antibodies were found in all five regions (Burgas, Sliven, Stara Zagora, Haskovo, and Kardzhali) at frequencies of 36/155 (23.2%; 95% CI: 16.8-30.7%; ranging by region from 6.4% to 50%) and 31/155 (20%; 95% CI: 14-27.2%; ranging by region from 10% to 30.8%), respectively. Antibodies against Ehrlichia spp. were found in horses from three regions (Burgas, Stara Zagora, and Haskovo) at a rate of 6/155 (3.9%; 95% CI: 1.4-8.2%; ranging by region from 5.7% to 6.4%). The combination of B. burgdorferi/A. phagocytophilum (11/155; 7.1%; 95% CI: 3.6-12.3%) was the most common coexposure observed, followed by B. burgdorferi/Ehrlichia spp. (2/155; 1.3%; 95% CI: 0.2-4.6%) and A. phagocytophilum/Ehrlichia spp. (1/155; 0.6%; 95% CI: 0-3.5%). The study shows that horses in Bulgaria are exposed or coexposed to three tick-transmitted zoonotic bacterial species. Furthermore, it reports Ehrlichia spp. seroreactivity in equines in Europe.

First molecular evidence of equine granulocytic anaplasmosis in Pakistan

Anaplasma phagocytophilum (A. phagocytophilum) is an obligate intracellular bacterium that causes equine granulocytic anaplasmosis (EGA) disease in equines. This pathogen has zoonotic potential, which makes it very important to be detected and controlled as early as possible. This study was aimed to assess the molecular prevalence, associated risk factors of EGA along with its effects on various hematological parameters. This study revealed an overall 10.67% prevalence in equine. Horses showed highest prevalence followed by mules and donkeys presenting 11.86, 10.53 and 9.43% prevalence, respectively. The samples were confirmed for anaplasmosis through sequencing. The BLAST queries confirmed very high homology of our isolates with Chinese and Japanese isolates of A. phagocytophilum (Accession no's; KX505303, KY242456 and LC002836). The phylogenetic analysis found the study isolates clustered with each other and this cluster closely resembled Chinese isolate of A. bovis (FJ169957), A. phagocytophilum (HQ872464) and A. phagocytophilum (NR_044762) human isolate from northern Minnesota and Wisconsin. The key risk factors identified for occurrence of EGA in equine species on the basis of univariable analysis were sex of animal, housing type, tick infestation, previous tick history and tick control status, type of acaricides used, rearing system and farm hygiene, respectively. The hematological parameters like Hemoglobin (Hb), Total Leukocyte Count (TLC), Total Erythrocytes Count (TEC), and granulocytes were decreased in diseased animals. The mules showed no typical hematological variations which make sense for its nature as carrier of infection to the susceptible species. This is the first molecular evidence of EGA in Pakistan. The disease needs to be handled seriously as it has zoonotic potential. The animals should be properly attended in disease conditions as leukopenia, neutropenia and lymphopenia can aggravate the condition by making the animal prone to secondary infections.

Prevalence of Anaplasma phagocytophilum infection in feral cats in Massachusetts

Objectives

The primary objective of this study was to determine the prevalence of Anaplasma phagocytophilum infection and exposure in adult feral cats in Massachusetts, an endemic area for A phagocytophilum and its tick vector Ixodes scapularis. The secondary objective was to determine if there were correlations between A phagocytophilum infection and the presence of anemia and thrombocytopenia.

Methods

Blood samples were collected between June and December 2015 from 175 apparently healthy adult feral cats that were presented to trap and release spay/neuter centers in Massachusetts. Complete blood count, blood smear evaluation, SNAP 4Dx Plus test (IDEXX) and A phagocytophilum PCR were performed on all samples to document acute infection (PCR-positive and/or inclusions observed on blood smear) and exposure to A phagocytophilum (SNAP 4Dx Plus-positive for A phagocytophilum antibodies).

Results

The prevalence of exposure to A phagocytophilum in feral cats in Massachusetts was 9.7%, whereas the prevalence of acute infection was 6.9%. All blood smears were negative for Anaplasma species inclusions; therefore, acute infection was defined as testing positive on PCR analysis. No statistically significant correlations were identified for cats that were positive for A phagocytophilum on PCR analysis or SNAP 4Dx Plus test and the presence of anemia or thrombocytopenia.

Conclusions and relevance

The prevalence of A phagocytophilum exposure in feral cats approaches 10% and is higher than the previously reported national average prevalence of 4.3% in the USA. A phagocytophilum infection may be an emerging infectious disease in cats. Further research is needed to determine the prevalence of clinical illness associated with A phagocytophilum infection in cats living in endemic areas.

Molecular evidence for bacterial pathogens in Ixodes ricinus ticks infesting Shetland ponies

Ixodes ricinus has the potential to transmit zoonotic pathogens to humans and domestic animals. The feeding I. ricinus (n = 1737) collected from 49 Shetland ponies and questing ones from vegetation (n = 371) were tested for the presence and differentiation of the bacterial species. DNA of I. ricinus ticks was examined with PCR and sequencing analysis to identify species of Borrelia burgdorferi sensu lato (Bbsl), Anaplasma phagocytophilum and Rickettsia spp. Altogether, 24.3 % I. ricinus of the infested horses and 12.4 % ticks from vegetation carried at least one pathogen species. Horse-feeding ticks (19.2 %) were significantly more frequently infected with Borrelia spp. than questing ticks (4.8 %). Among Bbsl species, in I. ricinus infesting ponies, B. garinii, B. afzelii, B. burgdorferi sensu stricto, B. valaisiana and B. lusitanie and one species, B. miyamotoi related to relapsing fever group, were detected. The 73 flaB gene sequences of Borrelia obtained from feeding I. ricinus have been deposited in GenBank. Among Rickettsia species, two were identified: R. helvetica which was dominant and R. monacensis. Infections with more than one pathogenic species, involving mostly Bbsl and R. helvetica were detected in 6.3 % of infected ticks collected from horses. Shetland ponies may play an important role in the epidemiological cycle of Bbsl and probably could contribute to the natural cycle of A. phagocytophilum and R. helvetica as host for infected ticks. The awareness about these infectious agents in ticks from ponies might be an important criterion for the risk assessment of human diseases, especially as these animals are maintained for recreational purposes.

Seroprevalence of Borrelia burgdorferi in Horses Presented for Coggins Testing in Southwest Virginia and Change in Positive Test Results Approximately 1 Year Later

Background

Lyme disease can affect people, dogs, and horses, but it remains poorly understood, especially in the horse. Determining the seroprevalence of Borrelia burgdorferi in horses in different geographic areas will enable better understanding of the epidemiology of the disease, thus improving diagnosis and treatment of affected animals.

Hypothesis

To determine the seroprevalence of B. burgdorferi in horses in southwest Virginia.

Animals

Horses presented for routine Coggins testing from January 2013 to January 2014 had additional blood drawn for Lyme Multiplex Assay testing.

Methods

Of 492 samples collected, 250 samples were analyzed using the Lyme Multiplex Assay. Of the 83 horses that had positive test results to at least 1 outer surface protein (Osp), 63 were available for follow‐up testing 5–17 months later (June 2014).

Results

Thirty‐three percent of horses had positive results for antibodies to at least 1 Osp. Horses with a positive outer surface protein F (OspF) result were older (14.5 ± 0.79) than horses with a negative OspF result (11.6 ± 0.53). Of the horses available for follow‐up testing, 63% had the same result as that of the initial test. There was no difference in test result between initial and follow‐up testing.

Conclusions

Horses seropositive to B. burgdorferi are common in Virginia, and older horses are more likely to have a positive test result for OspF than younger horses. Follow‐up testing indicated that the majority of horses that were positive on initial testing did not have a different test result 5–17 months later.

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.

Serological Detection of Borrelia burgdorferi among Horses in Korea

Lyme disease is a tick-borne zoonotic infectious disease caused by Borrelia burgdorferi. The present study assessed the infection status of B. burgdorferi among horses reared in Korea using ELISA and PCR. Between 2009 and 2013, blood samples were collected from 727 horses throughout Korea. Data for each animal including age, gender, breed, and region of sample collection were used for epidemiological analysis. Overall, 38 (5.2%; true prevalence: 5.5%) of 727 horses were seropositive by ELISA. There were statistically significant differences according to breed and region (P<0.001) whose differences might be attributed to the ecology of vector ticks and climate conditions. Using 2 nested PCR, none of the samples tested positive for B. burgdorferi. Thus, a positive ELISA result can indicate only that the tested horse was previously exposed to B. burgdorferi, with no certainty over the time of exposure. Since global warming is likely to increase the abundance of ticks in Korea, continuous monitoring of tick-borne diseases in Korean horses is needed.

Anaplasma marginale and Anaplasma phagocytophilum: Rickettsiales pathogens of veterinary and public health significance

Anaplasma marginale and Anaplasma phagocytophilum are the most important tick-borne bacteria of veterinary and public health significance in the family Anaplasmataceae. The objective of current review is to provide knowledge on ecology and epidemiology of A. phagocytophilum and compare major similarities and differences of A. marginale and A. phagocytophilum. Bovine anaplasmosis is globally distributed tick-borne disease of livestock with great economic importance in cattle industry. A. phagocytophilum, a cosmopolitan zoonotic tick transmitted pathogen of wide mammalian hosts. The infection in domestic animals is generally referred as tick-borne fever. Concurrent infections exist in ticks, domestic and wild animals in same geographic area. All age groups are susceptible, but the prevalence increases with age. Movement of susceptible domestic animals from tick free non-endemic regions to disease endemic regions is the major risk factor of bovine anaplasmosis and tick-borne fever. Recreational activities or any other high-risk tick exposure habits as well as blood transfusion are important risk factors of human granulocytic anaplasmosis. After infection, individuals remain life-long carriers. Clinical anaplasmosis is usually diagnosed upon examination of stained blood smears. Generally, detection of serum antibodies followed by molecular diagnosis is usually recommended. There are problems of sensitivity and cross-reactivity with both the Anaplasma species during serological tests. Tetracyclines are the drugs of choice for treatment and elimination of anaplasmosis in animals and humans. Universal vaccine is not available for either A. marginale or A. phagocytophilum, effective against geographically diverse strains. Major control measures for bovine anaplasmosis and tick-borne fever include rearing of tick-resistant breeds, endemic stability, breeding Anaplasma-free herds, identification of regional vectors, domestic/wild reservoirs and control, habitat modification, biological control, chemotherapy, and vaccinations (anaplasmosis and/or tick vaccination). Minimizing the tick exposure activities, identification and control of reservoirs are important control measures for human granulocytic anaplasmosis.

Serological survey of Ehrlichia species in dogs, horses and humans: zoonotic scenery in a rural settlement from southern Brazil

The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses and 100 humans were used. Fifty-six out of 132 (42.4%) dogs were seropositive for E. canis. Dogs > one year were more likely to be seropositive for E. canis than dogs ≤ one year (p = 0.0051). Ten/16 (62.5%) and 8/16 (50%) horses were seropositive by the commercial ELISA and IFA, respectively. Five out of 100 (5%) humans were seropositive for E. canis and E. chaffeensis. Rhipicephalus sanguineus (n = 291, 97.98%) on dogs and Amblyomma cajennense (n = 25, 96.15%) on horses were the most common ticks found. In conclusion, anti-Ehrlichia spp. antibodies were found in horses; however, the lack of a molecular characterization precludes any conclusion regarding the agent involved. Additionally, the higher seroprevalence of E. canis in dogs and the evidence of anti-Ehrlichia spp. antibodies in humans suggest that human cases of ehrlichiosis in Brazil might be caused by E. canis, or other closely related species.

Anaplasma phagocytophilum--a widespread multi-host pathogen with highly adaptive strategies

The bacterium Anaplasma phagocytophilum has for decades been known to cause the disease tick-borne fever (TBF) in domestic ruminants in Ixodes ricinus-infested areas in northern Europe. In recent years, the bacterium has been found associated with Ixodes-tick species more or less worldwide on the northern hemisphere. A. phagocytophilum has a broad host range and may cause severe disease in several mammalian species, including humans. However, the clinical symptoms vary from subclinical to fatal conditions, and considerable underreporting of clinical incidents is suspected in both human and veterinary medicine. Several variants of A. phagocytophilum have been genetically characterized. Identification and stratification into phylogenetic subfamilies has been based on cell culturing, experimental infections, PCR, and sequencing techniques. However, few genome sequences have been completed so far, thus observations on biological, ecological, and pathological differences between genotypes of the bacterium, have yet to be elucidated by molecular and experimental infection studies. The natural transmission cycles of various A. phagocytophilum variants, the involvement of their respective hosts and vectors involved, in particular the zoonotic potential, have to be unraveled. A. phagocytophilum is able to persist between seasons of tick activity in several mammalian species and movement of hosts and infected ticks on migrating animals or birds may spread the bacterium. In the present review, we focus on the ecology and epidemiology of A. phagocytophilum, especially the role of wildlife in contribution to the spread and sustainability of the infection in domestic livestock and humans.

Antibodies to OspC, OspF and C6 antigens as indicators for infection with Borrelia burgdorferi in horses

REASONS FOR PERFORMING STUDY

Lyme disease is caused by Borrelia burgdorferi, which is transmitted by infected ticks (Ixodes spp.). Reports on Lyme disease in horses have increased in recent years. Nevertheless, the diagnosis of Lyme disease in horses is still challenging owing to its vague clinical presentation and the limitations of diagnostic tests.

OBJECTIVES

This study used a new serological Lyme multiplex assay to examine antibody responses to 3 antigens of B. burgdorferi, outer surface protein (Osp) C, OspF and C6, and to verify their use as markers for early and late infection stages in horses.

METHODS

Multiplex analysis of antibodies to OspC, OspF and C6 in equine patient sera (n = 191) was performed. A subset of the sera (n = 90) was also tested using a commercial C6-based Lyme test.

RESULTS

Antibodies to OspF and C6 highly correlate as reliable markers of infection with B. burgdorferi in horses. Antibodies to OspC, which have been confirmed as early infection markers in man and dogs, were only detected in some patient sera, suggesting that OspC antibodies are indicators of early infection in horses. Commercial C6 testing identified most infected horses but also resulted in false positive and false negative interpretations.

CONCLUSIONS

Serological multiplex testing is a rapid and quantitative diagnostic method to confirm infection with B. burgdorferi and to identify the stage of infection. In horses with risk of exposure and clinical signs, multiplex testing supports the diagnosis of Lyme disease.

POTENTIAL RELEVANCE

Antimicrobial treatment of B. burgdorferi is time sensitive. Treatment success decreases with time of persistent infection, while the risk of developing chronic disease increases. The ability to identify early infection with B. burgdorferi provides practitioners and clinicians with a tool to improve the diagnosis of equine Lyme disease and make treatment decisions.

Anaplasma phagocytophilum in horses and ticks in Tunisia

Background

Anaplasma phagocytophilum , the causative agent of granulocytic anaplasmosis, affects several species of wild and domesticated mammals, including horses. We used direct and indirect methods to compare and evaluate exposure to A. phagocytophilum in horses in northern Tunisia.

Methods

Serum from 60 horses was tested by IFA for antibodies to A. phagocytophilum , and whole blood was tested for A. phagocytophilum 16S rRNA gene using a nested-PCR. To examine the risk of A. phagocytophilum transmission, 154 ticks that had been collected from horses were examined for the presence of A. phagocytophilum by nested-PCR targeting 16S rRNA gene.

Results

This is the first time that A. phagocytophilum has been detected in horses in Tunisia, with an overall seroprevalence of 40/60 (67%). Six of the seroreactive samples (10%) had an IFA titer of 1:80, 14 (23%) of 1:160, 8 (13%) of 1:320 and 12 (20%) a titer 1 ≥ 640. The seroprevalence revealed no significant regional and sex differences. In contrast, a significant difference was observed between breeds. Eight (13%) of the horses were positive for A. phagocytophilum in the PCR, with no significant breed and age differences. Hyalomma marginatum was a predominant tick species (130/154), and 3 were infected by A. phagocytophilum (a prevalence of 2.3%). The concordance rate of A. phagocytophilum detection between IFA and PCR had a k value of −0.07.

Conclusions

The results presented in this study suggest that horses infested by ticks in Tunisia are exposed to A. phagocytophilum.

Anaplasma phagocytophilum seroprevalence in equids: a survey in Sicily (Italy)

This study was undertaken to determine the prevalence of Anaplasma phagocytophilum infection in Equidae and investigate the possibility of exposure to the organism in Sicily (Southern Italy). During the study blood samples were collected in horses and donkeys housed in five of the nine provinces of Sicilian Island. Of 133 horses and 100 donkeys tested, respectively 9.0% and 6.0% were seroactive (IFAT) with A. phagocytophilum antigen. In only 4.7% of the horses, specific A. phagocytophilum DNA was recorded; in donkey, Anaplasma DNA was not found. Our results indicate a low prevalence of A. phagocytophilum in Sicilian equids. This condition does not justify the exclusion of equids from prophylactic plans for this multihost pathogen infection, a zoonosis with a wide distribution in other European countries. However, further studies are necessary to elucidate the possible mechanisms that involve the Equidae as host of this pathogen.

Genetic variants of Anaplasma phagocytophilum from 14 equine granulocytic anaplasmosis cases

Background

Equine Granulocytic Anaplasmosis (EGA) is caused by Anaplasma phagocytophilum, a tick-transmitted, obligate intracellular bacterium. In Europe, it is transmitted by Ixodes ricinus. A large number of genetic variants of A. phagocytophilum circulate in nature and have been found in ticks and different animals. Attempts have been made to assign certain genetic variants to certain host species or pathologies, but have not been successful so far. The purpose of this study was to investigate the causing agent A. phagocytophilum of 14 cases of EGA in naturally infected horses with molecular methods on the basis of 4 partial genes (16S rRNA, groEL, msp2, and msp4).

Results

All DNA extracts of EDTA-blood samples of the horses gave bands of the correct nucleotide size in all four genotyping PCRs. Sequence analysis revealed 4 different variants in the partial 16S rRNA, groEL gene and msp2 genes, and 3 in the msp4 gene. One 16S rRNA gene variant involved in 11 of the 14 cases was identical to the "prototype" variant causing disease in humans in the amplified part [GenBank: U02521]. Phylogenetic analysis revealed as expected for the groEL gene that sequences from horses clustered separately from roe deer. Sequences of the partial msp2 gene from this study formed a separate cluster from ruminant variants in Europe and from all US variants.

Conclusions

The results show that more than one variant of A. phagocytophilum seems to be involved in EGA in Germany. The comparative genetic analysis of the variants involved points towards different natural cycles in the epidemiology of A. phagocytophilum, possibly involving different reservoir hosts or host adaptation, rather than a strict species separation.

Antibody profiling of Borrelia burgdorferi infection in horses

Infection with Borrelia burgdorferi is common in horses and ponies from the New England and mid-Atlantic regions of the United States. Here, we evaluated luciferase immunoprecipitation systems (LIPS) for profiling antibody responses against three different antigenic targets for the diagnosis of equine B. burgdorferi infection. LIPS testing of horse serum samples suspected of Lyme infection revealed that approximately 75% of the horse samples (114/159) were seropositive against the synthetic VOVO antigen, comprising repeated immunodominant C6 epitopes as well as OspC immunodominant epitopes. A comparison of VOVO and immunofluorescence assays (IFA) showed that 51% of the samples were positive in both assays (VOVO(+)/IFA(+)), 13% were VOVO(-)/IFA(+), 21% were VOVO(+)/IFA(-), and 15% were negative in both. To further understand humoral responses to B. burgdorferi and reconcile the diagnostic differences between IFA and VOVO, two additional B. burgdorferi LIPS tests were performed with DbpA and DbpB. Robust seropositive antibody responses against DbpA and/or DbpB were detected in 98% (79/81) of the VOVO(+)/IFA(+) and 93% (50/54) of the discrepant samples. Additionally, some of the samples negative by both VOVO and IFA showed immunoreactivity against DbpA and/or DbpB. Overall, 94% of the suspected horse samples were seropositive by LIPS, and heat map analysis revealed that seropositive samples often were immunoreactive with at least two of the three antigens. These results suggest that LIPS tests employing multiple recombinant antigens offer a promising approach for the evaluation of antibody responses in Lyme disease.

Seroprevalence of Anaplasma phagocytophilum in horses in the Czech Republic

Anaplasma phagocytophilum is the aetiological agent of equine granulocytic anaplasmosis (EGA). The aim of this survey was to assess the prevalence of anti-A. phagocytophilum antibodies in the horse population of the Czech Republic (CZ) and to investigate possible links between seropositivity and the geographic origin, age, and/or sex of the tested horses. Antibodies against A. phagocytophilum were screened using an indirect fluorescent antibody method (IFA). Serum samples from 96 healthy horses from 8 localities (7 within the CZ and one control upland/tick-free locality in Ukraine) were examined. While the controls tested negative, the seroprevalence in the Czech localities was estimated at 73%, which suggests that subclinical EGA is common among horses in the CZ. Significant differences between seropositivity rates in individual stables were demonstrated (explicable by the different environment and/or management styles of the horses stabled therein). Horses in stables from which previous manifest cases had been reported tended to have higher average titres. Mares displayed a somewhat higher seropositivity rate than did stallions; age had no demonstrable effect upon the serological status of the examined horses.