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Development of a Multiplex PCR and Magnetic DNA Capture Assay for Detecting Six Species Pathogens of the Genera Anaplasma and Ehrlichia in Canine, Bovine, Caprine and Ovine Blood Samples from Grenada, West Indies. Pathogens 2021; 10:pathogens10020192. [PMID: 33578784 PMCID: PMC7916465 DOI: 10.3390/pathogens10020192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/03/2021] [Accepted: 02/07/2021] [Indexed: 02/08/2023] Open
Abstract
Infections with tick-borne pathogens belonging to Anaplasma/Ehrlichia in various vertebrate hosts are a persistent problem resulting in nonspecific clinical signs during early infection. Diagnosis of single and multi-infections with these pathogens, causing diseases in companion/agricultural animals and people, remains a challenge. Traditional methods of diagnosis, such as microscopy and serology, have low sensitivity and specificity. Polymerase chain reaction (PCR) assays are widely used to detect early-phase infections, since these have high sensitivity and specificity. We report the development and validation of an assay involving PCR followed by magnetic capture method using species-specific oligonucleotides to detect six Anaplasma/Ehrlichia species pathogens in canine, bovine, caprine, and ovine blood samples. Overall, the assay application to 455 samples detected 30.1% (137/455) positives for one or more out of six screened pathogens. Single-pathogen infections were observed in 94.9% (130/137) of the positive samples, while co-infections were detected in 5.1% (7/137). Anaplasma marginale infection in cattle had the highest detection rate (34.4%), followed by canines positive for Anaplasma platys (16.4%) and Ehrlichia canis (13.9%). The assay aided in documenting the first molecular evidence for A. marginale in cattle and small ruminants and Ehrlichia chaffeensis and Ehrlichia ewingii in dogs in the Caribbean island of Grenada.
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Mylonakis ME, Theodorou KN. Canine Monocytic Ehrlichiosis: An Update on Diagnosis and Treatment. ACTA VET-BEOGRAD 2017. [DOI: 10.1515/acve-2017-0025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Abstract
Canine monocytic ehrlichiosis (CME) is a tick-borne disease of worldwide distribution. The major causative agent is Ehrlichia canis, a gram-negative, obligate intracellular, pleomorphic bacterium of the genus Ehrlichia, which infects monocytes, macrophages and lymphocytes, forming intracytoplasmic, membrane-bound bacterial aggregates, called morulae. After an incubation period of 8-20 days, the course of E. canis infection, can be sequentially divided into acute, subclinical and chronic phases, although these phases can hardly be distinguished in the clinical setting. Clinical recovery is the typical outcome of acutely infected dogs, entering the subclinical phase, during which they show no or minimal clinical signs and/or mild hematological abnormalities. Immunocompetent dogs may eliminate the infection during the acute or subclinical phases, but an unpredictable proportion of dogs will eventually develop the chronic phase, characterized by aplastic pancytopenia and high mortality, due to septicemia and/or severe bleeding. This article outlines briefly the pathogenesis of CME due to E. canis, and more thoroughly reviews the recent scientific literature pertaining to the diagnosis and treatment of this devastating disease.
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Affiliation(s)
- Mathios E. Mylonakis
- Konstantina N. Companion Animal Clinic, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki , Greece
| | - Konstantina N. Theodorou
- Companion Animal Clinic, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki , Greece
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Cardinot CB, Silva JES, Yamatogi RS, Nunes CM, Biondo AW, Vieira RFC, Junior JPA, Marcondes M. Detection ofEhrlichia canis, Babesia vogeli, andToxoplasma gondiiDNA in the Brain of Dogs Naturally Infected withLeishmania infantum. J Parasitol 2016; 102:275-9. [DOI: 10.1645/15-821] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Allison RW, Little SE. Diagnosis of rickettsial diseases in dogs and cats. Vet Clin Pathol 2013; 42:127-44. [DOI: 10.1111/vcp.12040] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robin W. Allison
- Department of Veterinary Pathobiology; Center for Veterinary Health Sciences; Oklahoma State University; Stillwater; OK; USA
| | - Susan E. Little
- Department of Veterinary Pathobiology; Center for Veterinary Health Sciences; Oklahoma State University; Stillwater; OK; USA
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Barber RM, Li Q, Diniz PPVP, Porter BF, Breitschwerdt EB, Claiborne MK, Birkenheuer AJ, Levine JM, Levine GJ, Chandler K, Kenny P, Nghiem P, Wei S, Greene CE, Kent M, Platt SR, Greer K, Schatzberg SJ. Evaluation of brain tissue or cerebrospinal fluid with broadly reactive polymerase chain reaction for Ehrlichia, Anaplasma, spotted fever group Rickettsia, Bartonella, and Borrelia species in canine neurological diseases (109 cases). J Vet Intern Med 2010; 24:372-8. [PMID: 20102497 DOI: 10.1111/j.1939-1676.2009.0466.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Vector-transmitted microorganisms in the genera Ehrlichia, Anaplasma, Rickettsia, Bartonella, and Borrelia are commonly suspected in dogs with meningoencephalomyelitis (MEM), but the prevalence of these pathogens in brain tissue and cerebrospinal fluid (CSF) of dogs with MEM is unknown. HYPOTHESIS/OBJECTIVES To determine if DNA from these genera is present in brain tissue and CSF of dogs with MEM, including those with meningoencephalitis of unknown etiology (MUE) and histopathologically confirmed cases of granulomatous (GME) and necrotizing meningoencephalomyelitis (NME). ANIMALS Hundred and nine dogs examined for neurological signs at 3 university referral hospitals. METHODS Brain tissue and CSF were collected prospectively from dogs with neurological disease and evaluated by broadly reactive polymerase chain reaction (PCR) for Ehrlichia, Anaplasma, Spotted Fever Group Rickettsia, Bartonella, and Borrelia species. Medical records were evaluated retrospectively to identify MEM and control cases. RESULTS Seventy-five cases of MUE, GME, or NME, including brain tissue from 31 and CSF from 44 cases, were evaluated. Brain tissue from 4 cases and inflammatory CSF from 30 cases with infectious, neoplastic, compressive, vascular, or malformative disease were evaluated as controls. Pathogen nucleic acids were detected in 1 of 109 cases evaluated. Specifically, Bartonella vinsonii subsp. berkhoffii DNA was amplified from 1/6 dogs with histopathologically confirmed GME. CONCLUSION AND CLINICAL IMPORTANCE The results of this investigation suggest that microorganisms in the genera Ehrlichia, Anaplasma, Rickettsia, and Borrelia are unlikely to be directly associated with canine MEM in the geographic regions evaluated. The role of Bartonella in the pathogenesis of GME warrants further investigation.
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Affiliation(s)
- R M Barber
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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Little SE, O'Connor TP, Hempstead J, Saucier J, Reichard MV, Meinkoth K, Meinkoth JH, Andrews B, Ullom S, Ewing SA, Chandrashekar R. Ehrlichia ewingii infection and exposure rates in dogs from the southcentral United States. Vet Parasitol 2010; 172:355-60. [PMID: 20541322 DOI: 10.1016/j.vetpar.2010.05.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 04/06/2010] [Accepted: 05/05/2010] [Indexed: 11/26/2022]
Abstract
We used PCR and a novel serologic assay to determine infection and exposure rates to Ehrlichia ewingii in dogs from an area of northeast Oklahoma and northwest Arkansas where Amblyomma americanum ticks are abundant. Of 143 dogs assayed, 13 (9.1%) harbored E. ewingii by PCR and 64 (44.8%) had antibodies to E. ewingii detected using a peptide-based microtiter plate ELISA. Dogs were more likely (P=0.001) to be positive by PCR if sampled in August (30.8%) but no association was found between seropositive status and month of collection of sample (P>0.05). Additional testing revealed PCR evidence of Ehrlichia chaffeensis (4/143; 2.8%) and Anaplasma platys (5/143; 3.5%) as well as antibodies reactive to E. chaffeensis (25/143; 17.5%), Ehrlichia canis (2/143; 1.4%), and Anaplasma spp. (8/143; 5.6%). Testing of another 200 dogs from the area revealed additional PCR and/or serologic evidence of E. ewingii, E. canis, E. chaffeensis, and A. platys. None of the 343 dogs evaluated had evidence of Borrelia burgdorferi exposure. These data support the interpretation that E. ewingii may be the primary agent of canine ehrlichiosis in this region, and suggest that diagnostic evaluation of dogs suspected to have a tick-borne disease should include assays targeting this organism.
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Affiliation(s)
- Susan E Little
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, USA.
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Hegarty BC, de Paiva Diniz PPV, Bradley JM, Lorentzen L, Breitschwerdt E. Clinical relevance of annual screening using a commercial enzyme-linked immunosorbent assay (SNAP 3Dx) for canine ehrlichiosis. J Am Anim Hosp Assoc 2009; 45:118-24. [PMID: 19411647 DOI: 10.5326/0450118] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Eighty-six dogs were selected based upon Ehrlichia (E.) canis SNAP 3Dx positive results to determine clinical relevance of annual E. canis screening. Immunofluorescence assay showed 72 (84%) of 86 dogs were seroreactive for E. canis. Polymerase chain reaction (PCR) revealed that 12 (14%) of 86 dogs had Ehrlichia deoxyribonucleic acid; seven had E. canis, four had E. ewingii, and one was coinfected with E. chaffeensis and E. ewingii. Thrombocytopenia (<164,000 platelets/microL) was found in 28 (39%) of 72 dogs. In this study, thrombocytopenia was frequently detected in healthy Ehrlichia SNAP 3Dx-positive dogs, whereas active infection was infrequently confirmed by PCR. Therefore, treatment based upon screening results alone is not recommended.
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Affiliation(s)
- Barbara C Hegarty
- Intracellular Pathogens Research Laboratory, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA
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Sasanelli M, Paradies P, Lubas G, Otranto D, de Caprariis D. Atypical clinical presentation of coinfection with Ehrlichia, Babesia and Hepatozoon species in a dog. Vet Rec 2009; 164:22-3. [PMID: 19122221 DOI: 10.1136/vr.164.1.22] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- M Sasanelli
- Department of Animal Health and Welfare, Faculty of Veterinary Medicine, University of Bari, Bari, Italy
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Stich RW, Schaefer JJ, Bremer WG, Needham GR, Jittapalapong S. Host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, Ehrlichia canis. Vet Parasitol 2008; 158:256-73. [PMID: 18963493 DOI: 10.1016/j.vetpar.2008.09.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 08/20/2008] [Accepted: 08/20/2008] [Indexed: 10/21/2022]
Abstract
The ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. Ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. Historically, advances in tick-borne disease control strategies have typically followed explication of tick-pathogen-vertebrate interactions, thus it is reasonable to expect novel, more sustainable approaches to control of these diseases as the transmission of their associated infections are investigated at the molecular through ecological levels. Better understanding of the interactions between E. canis and its canine and tick hosts would also elucidate similar interactions for other Ehrlichia species as well as the potential roles of canine sentinels, reservoirs and models of tick-borne zoonoses. This article summarizes natural exposure studies and experimental investigations of E. canis in the context of what is understood about biological vectors of tick-borne Anaplasmataceae.
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Affiliation(s)
- R W Stich
- Department of Veterinary Pathobiology, The University of Missouri, Columbia, MO 65211, USA.
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Delos Santos JRC, Boughan K, Bremer WG, Rizzo B, Schaefer JJ, Rikihisa Y, Needham GR, Capitini LA, Anderson DE, Oglesbee M, Ewing SA, Stich RW. Experimental infection of dairy calves with Ehrlichia chaffeensis. J Med Microbiol 2008; 56:1660-1668. [PMID: 18033836 DOI: 10.1099/jmm.0.47427-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human monocytic ehrlichiosis (HME) is a zoonotic emerging tick-borne disease with clinical signs that range from mild symptoms to multiple organ failure and death. Ehrlichia chaffeensis, the aetiologic agent of HME, is reported to infect a divergent range of mammals. Although cattle are common hosts of the primary vector of this pathogen, the susceptibility of this host to E. chaffeensis has not been reported to date. This study was undertaken to determine if cattle could provide a useful infection model of E. chaffeensis. Dairy calves were injected with DH82 cells infected with the Arkansas, St Vincent or 91HE17 strain of E. chaffeensis, and monitored for signs of clinical ehrlichiosis and for infection of peripheral blood and ticks by PCR assay. Splenectomized and spleen-intact calves were injected with cryopreserved stabilates of E. chaffeensis-infected DH82 cells for the first experiment. Mild clinical signs were occasionally observed among these calves, and only two blood samples were PCR-positive, while several ticks fed on each calf tested PCR-positive. The second experiment involved injection of normal calves with active cultures of the same E. chaffeensis strains. Interestingly, three of six calves inoculated with active cultures became recumbent and died or had to be euthanized. All of the surviving calves in this experiment tested PCR-positive on multiple dates, but fewer ticks fed on these calves were PCR-positive. These results suggest that a bovine disease model could facilitate the understanding of factors that affect the severity of HME.
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Affiliation(s)
- Jose R C Delos Santos
- Department of Veterinary Preventive Medicine, Ohio State University, Columbus, OH, USA
| | - Kirsten Boughan
- Department of Veterinary Preventive Medicine, Ohio State University, Columbus, OH, USA
| | - William G Bremer
- Department of Veterinary Preventive Medicine, Ohio State University, Columbus, OH, USA
| | - Brian Rizzo
- Department of Veterinary Preventive Medicine, Ohio State University, Columbus, OH, USA
| | - John J Schaefer
- Department of Entomology, Ohio State University, Columbus, OH, USA
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, Ohio State University, Columbus, OH, USA
| | - Glen R Needham
- Department of Entomology, Ohio State University, Columbus, OH, USA
| | - L A Capitini
- University Laboratory Animal Resources, Ohio State University, Columbus, OH, USA
| | - David E Anderson
- Department of Veterinary Clinical Sciences, Ohio State University, Columbus, OH, USA
| | - Michael Oglesbee
- Department of Veterinary Biosciences, Ohio State University, Columbus, OH, USA
| | - S A Ewing
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, USA
| | - Roger W Stich
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
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Sirigireddy KR, Mock DC, Ganta RR. Multiplex Detection of Ehrlichia and Anaplasma Pathogens in Vertebrate and Tick Hosts by Real-Time RT-PCR. Ann N Y Acad Sci 2006; 1078:552-6. [PMID: 17114775 DOI: 10.1196/annals.1374.108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tick-borne rickettsial infections are responsible for many emerging diseases in humans and several vertebrates. These include human infections with Ehrlichia chaffeensis, Ehrlichia ewingii and Anaplasma phagocytophilum. As single or co-infections can result from a tick bite, the availability of a rapid, multiplex molecular test will be valuable for timely diagnosis and treatment. We recently described a muliplex-molecular test that can detect single or co-infections with up to five Ehrlichia and Anaplasma species. We reported that the test has the sensitivity to identify single infections in the canine host with E. chaffeensis, E. canis, E. ewingii, A. phagocytophilum, and A. platys and co-infection with E. canis and A. platys. In this study, ticks were collected from different parts of the state of Kansas during summer months of the year 2003 and tested for the presence of infection using the molecular test. The analysis revealed a minimum of 3.66% of the ticks to be positive for either E. chaffeensis or E. ewingii in A. americanum and Dermacenter species. This assay will be valuable in monitoring infections in dogs and ticks, and with minor modifications it can be used for diagnosing infections in people and other vertebrates.
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Affiliation(s)
- Kamesh R Sirigireddy
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506, USA
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Sirigireddy KR, Ganta RR. Multiplex detection of Ehrlichia and Anaplasma species pathogens in peripheral blood by real-time reverse transcriptase-polymerase chain reaction. J Mol Diagn 2005; 7:308-16. [PMID: 15858156 PMCID: PMC1867522 DOI: 10.1016/s1525-1578(10)60559-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2004] [Indexed: 11/28/2022] Open
Abstract
Tick-borne infections are responsible for many emerging diseases in humans and several vertebrates. These include human infections with Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia ewingii. Because single or co-infections can result from tick bites, the availability of a rapid, multiplex molecular test will be valuable for timely diagnosis and treatment. Here, we describe a multiplex molecular test that can detect single or co-infections with up to five Ehrlichia and Anaplasma species. The test protocol includes the magnetic capture-based purification of 16S ribosomal RNA, its enrichment, and specific-pathogen(s) detection by real-time reverse transcriptase-polymerase chain reaction. We also report a unique cloning strategy to develop positive controls in the absence of a pathogen's genomic DNA. The test was assessed by examining blood samples from dogs suspected to be positive for ehrlichiosis. The dog was chosen as the model system because it is susceptible to acquire infections with up to five pathogens of the genera Ehrlichia and Anaplasma. The test identified single infections in the canine host with E. chaffeensis, E. canis, E. ewingii, A. phagocytophilum, and A. platys and co-infection with E. canis and A. platys. The multipathogen detection and novel positive control development procedures described here will be valuable in monitoring infections in people, other vertebrates, and ticks.
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Affiliation(s)
- Kamesh R Sirigireddy
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Ave., Manhattan, Kansas 66506, USA
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Abstract
Ehrlichiosis is a term that has been used to describe infection with any of a number of related intracellular, vector-borne pathogens. A recent reclassification has resulted in the transfer of several species previously known as Ehrlichia to the genus Anaplasma or Neorickettsia. Ehrlichia and Anaplasma are transmitted largely through the bite of infected ticks, while vectors for Neorickettsia include trematodes and the intermediate hosts (i.e., fish, snails, and insects) involved in the trematode life cycle. Dogs (and cats) are susceptible to infection with several of these pathogens, and veterinarians should be aware of the similarities and differences between E canis and related infections. Pets with suggestive clinical signs and laboratory abnormalities may be started on doxycycline pending specific diagnostic testing. The veterinarian practicing in endemic areas must understand the implications and limitations of serologic and molecular testing to confirm a diagnosis. For animals in endemic areas, prevention of exposure to vectors can lessen the risk of disease for pets and might lessen the potential for animals to become carriers of disease for their human companions.
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Affiliation(s)
- Leah A Cohn
- College of Veterinary Medicine, University of Missouri-Columbia, 379 East Campus, Clydesdale Hall, Columbia, MO 65211, USA.
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Goodman RA, Hawkins EC, Olby NJ, Grindem CB, Hegarty B, Breitschwerdt EB. Molecular identification of Ehrlichia ewingii infection in dogs: 15 cases (1997-2001). J Am Vet Med Assoc 2003; 222:1102-7. [PMID: 12710774 DOI: 10.2460/javma.2003.222.1102] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine historical, physical examination, hematologic, and serologic findings in dogs with Ehrlichia ewingii infection. DESIGN Retrospective study. ANIMALS 15 dogs. PROCEDURE In all dogs, infection with E ewingii was confirmed with a polymerase chain reaction (PCR) assay. Follow-up information and clarification of information recorded in the medical records was obtained by telephone interviews and facsimile correspondence with referring veterinarians and owners. RESULTS Fever and lameness were the most common findings with each occurring in 8 dogs. Five dogs had neurologic abnormalities including ataxia, paresis, proprioceptive deficits, anisocoria, intention tremor, and head tilt. Neutrophilic polyarthritis was identified in 4 dogs. No clinical signs were reported in 3 dogs. The predominant hematologic abnormality was thrombocytopenia, which was identified in all 12 dogs for which a platelet count was available. Reactive lymphocytes were seen in 5 of 13 dogs. Concurrent infection with another rickettsial organism was identified in 4 dogs. Of the 13 dogs tested, 7 were seroreactive to E canis antigens. Morulae consistent with E ewingii infection were identified in neutrophils in 8 dogs. Treatment with doxycycline, with or without prednisone, resulted in a rapid, favorable clinical response in the 9 dogs for which follow-up information was available. CONCLUSIONS AND CLINICAL RELEVANCE Results suggest that PCR testing for E ewingii infection should be considered in dogs with fever, neutrophilic polyarthritis, unexplained ataxia or paresis, thrombocytopenia, or unexplained reactive lymphocytes, and in dogs with clinical signs suggestive of ehrlichiosis that are seronegative for E canis. Following treatment with doxycycline, the prognosis for recovery is good.
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Affiliation(s)
- Robert A Goodman
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
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Abstract
Histologic examination of eyes and brains of 27 dogs experimentally infected with either Ehrlichia canis, E. ewingii, E. chaffeensis, or human granulocytic ehrlichia (HGE) was conducted in the course of several experiments, the primary objectives of which were to investigate the susceptibility of the domestic dog to infection with various ehrlichial species and to assess the ability of ixodid tick species to acquire and transmit those infections. Uveitis and meningitis occurred in each of the dogs infected with E. canis but was not observed in dogs infected with the other Ehrlichia species. The inflammatory infiltrate was predominantly lymphocytic, monocytic, and plasmacytic; granulocytes were notably few. Ocular inflammation was most common and most intense in the ciliary body, becoming less intense in the choroid, iris, and retina, respectively. Meningitis was often accompanied by mild neuroparenchymal vascular cuffing and gliosis. The meningeal inflammatory cell infiltrate included a prominent monocyte population. Ocular and meningeal lesions were present in all E. canis-infected dogs from 22 through 200 days postexposure. Neither ocular nor brain lesions were observed with any of the other ehrlichial infections.
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Affiliation(s)
- R J Panciera
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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