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Johnson BV, Kumar R, Oishi S, Alexander S, Kasherman M, Vega MS, Ivancevic A, Gardner A, Domingo D, Corbett M, Parnell E, Yoon S, Oh T, Lines M, Lefroy H, Kini U, Van Allen M, Grønborg S, Mercier S, Küry S, Bézieau S, Pasquier L, Raynaud M, Afenjar A, Billette de Villemeur T, Keren B, Désir J, Van Maldergem L, Marangoni M, Dikow N, Koolen DA, VanHasselt PM, Weiss M, Zwijnenburg P, Sa J, Reis CF, López-Otín C, Santiago-Fernández O, Fernández-Jaén A, Rauch A, Steindl K, Joset P, Goldstein A, Madan-Khetarpal S, Infante E, Zackai E, Mcdougall C, Narayanan V, Ramsey K, Mercimek-Andrews S, Pena L, Shashi V, Schoch K, Sullivan JA, Pinto E Vairo F, Pichurin PN, Ewing SA, Barnett SS, Klee EW, Perry MS, Koenig MK, Keegan CE, Schuette JL, Asher S, Perilla-Young Y, Smith LD, Rosenfeld JA, Bhoj E, Kaplan P, Li D, Oegema R, van Binsbergen E, van der Zwaag B, Smeland MF, Cutcutache I, Page M, Armstrong M, Lin AE, Steeves MA, Hollander ND, Hoffer MJV, Reijnders MRF, Demirdas S, Koboldt DC, Bartholomew D, Mosher TM, Hickey SE, Shieh C, Sanchez-Lara PA, Graham JM, Tezcan K, Schaefer GB, Danylchuk NR, Asamoah A, Jackson KE, Yachelevich N, Au M, Pérez-Jurado LA, Kleefstra T, Penzes P, Wood SA, Burne T, Pierson TM, Piper M, Gécz J, Jolly LA. Partial Loss of USP9X Function Leads to a Male Neurodevelopmental and Behavioral Disorder Converging on Transforming Growth Factor β Signaling. Biol Psychiatry 2020; 87:100-112. [PMID: 31443933 PMCID: PMC6925349 DOI: 10.1016/j.biopsych.2019.05.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND The X-chromosome gene USP9X encodes a deubiquitylating enzyme that has been associated with neurodevelopmental disorders primarily in female subjects. USP9X escapes X inactivation, and in female subjects de novo heterozygous copy number loss or truncating mutations cause haploinsufficiency culminating in a recognizable syndrome with intellectual disability and signature brain and congenital abnormalities. In contrast, the involvement of USP9X in male neurodevelopmental disorders remains tentative. METHODS We used clinically recommended guidelines to collect and interrogate the pathogenicity of 44 USP9X variants associated with neurodevelopmental disorders in males. Functional studies in patient-derived cell lines and mice were used to determine mechanisms of pathology. RESULTS Twelve missense variants showed strong evidence of pathogenicity. We define a characteristic phenotype of the central nervous system (white matter disturbances, thin corpus callosum, and widened ventricles); global delay with significant alteration of speech, language, and behavior; hypotonia; joint hypermobility; visual system defects; and other common congenital and dysmorphic features. Comparison of in silico and phenotypical features align additional variants of unknown significance with likely pathogenicity. In support of partial loss-of-function mechanisms, using patient-derived cell lines, we show loss of only specific USP9X substrates that regulate neurodevelopmental signaling pathways and a united defect in transforming growth factor β signaling. In addition, we find correlates of the male phenotype in Usp9x brain-specific knockout mice, and further resolve loss of hippocampal-dependent learning and memory. CONCLUSIONS Our data demonstrate the involvement of USP9X variants in a distinctive neurodevelopmental and behavioral syndrome in male subjects and identify plausible mechanisms of pathogenesis centered on disrupted transforming growth factor β signaling and hippocampal function.
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Affiliation(s)
- Brett V Johnson
- University of Adelaide and Robinson Research Institute, Adelaide, Australia
| | - Raman Kumar
- University of Adelaide and Robinson Research Institute, Adelaide, Australia
| | - Sabrina Oishi
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Suzy Alexander
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia; Queensland Centre for Mental Health Research, Wacol, Queensland, Australia
| | - Maria Kasherman
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia; Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | | | - Atma Ivancevic
- University of Adelaide and Robinson Research Institute, Adelaide, Australia; BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado
| | - Alison Gardner
- University of Adelaide and Robinson Research Institute, Adelaide, Australia
| | - Deepti Domingo
- University of Adelaide and Robinson Research Institute, Adelaide, Australia
| | - Mark Corbett
- University of Adelaide and Robinson Research Institute, Adelaide, Australia
| | - Euan Parnell
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Sehyoun Yoon
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Tracey Oh
- Department of Medical Genetics, British Columbia Women's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew Lines
- Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Henrietta Lefroy
- Oxford Centre for Genomic Medicine, Oxford University Hospitals National Health Services Foundation Trust, Oxford, United Kingdom
| | - Usha Kini
- Oxford Centre for Genomic Medicine, Oxford University Hospitals National Health Services Foundation Trust, Oxford, United Kingdom
| | - Margot Van Allen
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sabine Grønborg
- Center for Rare Diseases, Department of Pediatrics and Department of Clinical Genetics, University Hospital Copenhagen, Copenhagen, Denmark
| | - Sandra Mercier
- Service de Génétique Médicale, Centre Hospitalier Universitaire Nantes and l'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Nantes, France
| | - Sébastien Küry
- Service de Génétique Médicale, Centre Hospitalier Universitaire Nantes and l'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Nantes, France
| | - Stéphane Bézieau
- Service de Génétique Médicale, Centre Hospitalier Universitaire Nantes and l'Institut du Thorax, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Nantes, France
| | - Laurent Pasquier
- Service de Génétique Clinique, Centre de Référence Déficiences Intellectuelles de Causes Rares, Centre Hospitalier Universitaire Hôpital Sud, Rennes, France
| | - Martine Raynaud
- Centre Hospitalier Régional Universitaire de Tours, Service de Génétique, Unité Nixte de Recherche 1253, iBrain, Université de Tours, Institut National de la Santé et de la Recherche Médicale, Tours, France
| | - Alexandra Afenjar
- Groupe de Recherche Clinique No. 19, ConCer-LD, Département de Génétique, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Centres de Référence Maladies Rares des Déficits Intellectuels de Causes Rares, Paris, France
| | - Thierry Billette de Villemeur
- Sorbonne Université, Groupe de Recherche Clinique No. 19, ConCer-LD, Neuropédiatrie, Centres de Référence Maladies Rares Neurogénétique, Institut National de la Santé et de la Recherche Médicale, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France
| | - Boris Keren
- Hôpital de la Pitié-Salpêtrière, Département de Génétique, Paris, France
| | - Julie Désir
- Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Martina Marangoni
- Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Nicola Dikow
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - David A Koolen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Peter M VanHasselt
- Department of Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marjan Weiss
- Department of Clinical Genetics, Vrije Universiteit University Medical Center, Amsterdam, The Netherlands
| | - Petra Zwijnenburg
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joaquim Sa
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Claudia Falcao Reis
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Instituto Universitário de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain; Centro de Investigación Biomédica en Red de Cáncer, Spain
| | - Olaya Santiago-Fernández
- Departamento de Bioquímica y Biología Molecular, Instituto Universitário de Oncología del Principado de Asturias, Universidad de Oviedo, Oviedo, Spain
| | | | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Pascal Joset
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Amy Goldstein
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | | | - Elena Infante
- Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elaine Zackai
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Carey Mcdougall
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, Arizona
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, Arizona
| | - Saadet Mercimek-Andrews
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Loren Pena
- Division of Human Genetics, Cincinnati Children's Hospital; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Vandana Shashi
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, North Carolina
| | - Kelly Schoch
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, North Carolina
| | - Jennifer A Sullivan
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, North Carolina
| | - Filippo Pinto E Vairo
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota; Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Pavel N Pichurin
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Sarah A Ewing
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Sarah S Barnett
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Eric W Klee
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - M Scott Perry
- Jane and John Justin Neuroscience Center, Cook Children's Medical Center, Fort Worth, Texas
| | - Mary Kay Koenig
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Catherine E Keegan
- Division of Genetics, Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Jane L Schuette
- Division of Genetics, Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Stephanie Asher
- Translational Medicine & Human Genetics, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yezmin Perilla-Young
- Division of Pediatric Genetics and Metabolism, University of North Carolina, Chapel Hill, North Carolina
| | - Laurie D Smith
- Division of Pediatric Genetics and Metabolism, University of North Carolina, Chapel Hill, North Carolina
| | | | - Elizabeth Bhoj
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Paige Kaplan
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Dong Li
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ellen van Binsbergen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bert van der Zwaag
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | - Matthew Page
- Translational Medicine, UCB Pharma, Braine-l'Alleud, Belgium
| | | | - Angela E Lin
- Medical Genetics Unit, Mass General Hospital for Children, Boston, Massachusetts
| | - Marcie A Steeves
- Medical Genetics Unit, Mass General Hospital for Children, Boston, Massachusetts
| | | | - Mariëtte J V Hoffer
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Margot R F Reijnders
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Serwet Demirdas
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | | | | | - Scott E Hickey
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio
| | - Christine Shieh
- David Geffen School of Medicine, University of California-Los Angeles, California
| | | | - John M Graham
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California
| | - Kamer Tezcan
- Department of Genetics, Kaiser Permanente, Sacramento, California
| | - G B Schaefer
- Section of Genetics and Metabolism, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Noelle R Danylchuk
- Department of Genetic Counseling, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Alexander Asamoah
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, Kentucky
| | - Kelly E Jackson
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, Kentucky
| | - Naomi Yachelevich
- Clinical Genetics Services, Department of Pediatrics, New York University School of Medicine, New York, New York
| | - Margaret Au
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California
| | - Luis A Pérez-Jurado
- University of Adelaide and Robinson Research Institute, Adelaide, Australia; Women's and Children's Hospital, Adelaide, Australia; South Australian Health and Medical Research Institute, Adelaide, South Australia; Hospital del Mar Research Institute, Network Research Centre for Rare Diseases and Universitat Pompeu Fabra, Barcelona, Spain
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stephen A Wood
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Thomas Burne
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia; Queensland Centre for Mental Health Research, Wacol, Queensland, Australia
| | - Tyler Mark Pierson
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California; Department of Neurology and the Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Michael Piper
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Jozef Gécz
- University of Adelaide and Robinson Research Institute, Adelaide, Australia; South Australian Health and Medical Research Institute, Adelaide, South Australia.
| | - Lachlan A Jolly
- University of Adelaide and Robinson Research Institute, Adelaide, Australia.
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Gupta A, Ewing SA, Renaud DL, Hasadsri L, Raymond KM, Klee EW, Gavrilova RH. Developmental delay, coarse facial features, and epilepsy in a patient with EXT2 gene variants. Clin Case Rep 2019; 7:632-637. [PMID: 30997052 PMCID: PMC6452521 DOI: 10.1002/ccr3.2010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/28/2018] [Accepted: 01/08/2019] [Indexed: 01/08/2023] Open
Abstract
We report a patient with developmental delay, autism, epilepsy, macrocephaly, facial dysmorphism, gastrointestinal, and behavioral issues due to EXT2 compound heterozygous likely pathogenic variants. This case report expands the EXT2 gene mutation database and the clinical spectrum of patients with deficiencies in the heparan sulfate pathway.
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Affiliation(s)
- Aditi Gupta
- Center for Individualized MedicineMayo ClinicRochesterMinnesota
- Department of Health Sciences ResearchMayo ClinicRochesterMinnesota
| | - Sarah A. Ewing
- Department of Clinical GenomicsMayo ClinicRochesterMinnesota
| | - Deborah L. Renaud
- Department of Pediatric and Adolescent MedicineMayo ClinicRochesterMinnesota
- Department of NeurologyMayo ClinicRochesterMinnesota
| | - Linda Hasadsri
- Department of Laboratory Medicine and PathologyMayo ClinicRochesterMinnesota
| | - Kimiyo M. Raymond
- Department of Clinical GenomicsMayo ClinicRochesterMinnesota
- Department of Laboratory Medicine and PathologyMayo ClinicRochesterMinnesota
| | - Eric W. Klee
- Center for Individualized MedicineMayo ClinicRochesterMinnesota
- Department of Health Sciences ResearchMayo ClinicRochesterMinnesota
- Department of Clinical GenomicsMayo ClinicRochesterMinnesota
- Department of Laboratory Medicine and PathologyMayo ClinicRochesterMinnesota
| | - Ralitza H. Gavrilova
- Department of Clinical GenomicsMayo ClinicRochesterMinnesota
- Department of NeurologyMayo ClinicRochesterMinnesota
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3
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Stoffel RT, McClure JC, Butcher MM, Johnson GC, Roland W, Cheng C, Sirigireddy KR, Ganta R, Boughan K, Ewing SA, Stich RW. Experimental infection of Rhipicephalus sanguineus with Ehrlichia chaffeensis. Vet Microbiol 2014; 172:334-8. [PMID: 24894131 DOI: 10.1016/j.vetmic.2014.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 01/11/2014] [Accepted: 04/23/2014] [Indexed: 10/25/2022]
Abstract
Ehrlichia chaffeensis, the etiologic agent of human monocytic ehrlichiosis, is a tick-borne rickettsial pathogen that is infective to a wide range of mammals, including dogs and people. Amblyomma americanum, the lone star tick, is considered the primary vector of E. chaffeensis, but this pathogen has been detected in other tick species, including the brown dog tick, Rhipicephalus sanguineus. We hypothesized that the Arkansas strain of E. chaffeensis is infective to R. sanguineus, and used a novel PCR assay to test for acquisition of this pathogen by R. sanguineus and A. americanum ticks that were simultaneously fed on experimentally infected dogs. Although E. chaffeensis was not frequently detected in peripheral blood of these dogs, the pathogen was detected in both tick species and in canine lung, kidney, lymph node, bone marrow and frontal lobe samples. One dog (AFL) was maintained for several years, and ticks again acquired E. chaffeensis from this dog 566 days after intradermal inoculation with E. chaffeensis, but the pathogen was not detected in ticks fed on the same dog at 764 or 1086 days after the intradermal inoculation.
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Affiliation(s)
- Ryan T Stoffel
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Jennifer C McClure
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Marion M Butcher
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Gayle C Johnson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Will Roland
- Department of Internal Medicine Infectious Disease Division, University of Missouri, Columbia, MO 65211, USA
| | - Chuanmin Cheng
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Kamesh R Sirigireddy
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Roman Ganta
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Kirstin Boughan
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - S A Ewing
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Roger W Stich
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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Behroozian AA, Chludzinski JP, Lo ES, Ewing SA, Waslawski S, Newton DW, Young VB, Aronoff DM, Walk ST. Detection of mixed populations of Clostridium difficile from symptomatic patients using capillary-based polymerase chain reaction ribotyping. Infect Control Hosp Epidemiol 2013; 34:961-966. [PMID: 23917911 DOI: 10.1086/671728] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the simultaneous occurrence of more than 1 Clostridium difficile ribotype in patients' stool samples at the time of diagnostic testing. METHODS Stool samples submitted for diagnostic testing for the presence of toxigenic C. difficile were obtained for 102 unique patients. A total of 95 single colonies of C. difficile per stool sample were isolated on selective media, subcultured alongside negative (uninoculated) controls, and polymerase chain reaction (PCR) ribotyped using capillary gel electrophoresis. RESULTS Capillary-based PCR ribotyping was successful for 9,335 C. difficile isolates, yielding a median of 93 characterized isolates per stool sample (range, 69-95). More than 1 C. difficile ribotype was present in 16 of 102 (16%) C. difficile infection (CDI) cases; 2 of the 16 mixtures were composed of at least 3 ribotypes, while the remaining 14 were composed of at least 2. CONCLUSIONS Deep sampling of patient stool samples coupled with capillary-based PCR ribotyping identified a high rate of mixed CDI cases compared with previous estimates. Studies seeking to quantify the clinical significance of particular C. difficile ribotypes should account for mixed cases of disease.
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Affiliation(s)
- Adam A Behroozian
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan
| | - Jeffrey P Chludzinski
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan
| | - Eugene S Lo
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan
| | - Sarah A Ewing
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan
| | - Sheila Waslawski
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan
| | - Duane W Newton
- Clinical Microbiology Laboratories, Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan
| | - Vincent B Young
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan
| | - David M Aronoff
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan
| | - Seth T Walk
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.,Department of Microbiology, Montana State University, Bozeman, Montana
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Walk ST, Micic D, Jain R, Lo ES, Trivedi I, Liu EW, Almassalha LM, Ewing SA, Ring C, Galecki AT, Rogers MAM, Washer L, Newton DW, Malani PN, Young VB, Aronoff DM. Clostridium difficile ribotype does not predict severe infection. Clin Infect Dis 2012; 55:1661-8. [PMID: 22972866 DOI: 10.1093/cid/cis786] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Studies of Clostridium difficile outbreaks suggested that certain ribotypes (eg, 027 and 078) cause more severe disease than other ribotypes. A growing number of studies challenge the validity of this hypothesis. METHODS We conducted a cross-sectional study of C. difficile infection (CDI) to test whether ribotype predicted clinical severity when adjusted for the influence of other predictors. Toxigenic C. difficile isolates were cultured from stool samples, screened for genes encoding virulence factors by polymerase chain reaction (PCR) and ribotyped using high-throughput, fluorescent PCR ribotyping. We collected data for 15 covariates (microbiologic, epidemiologic, and laboratory variables) and determined their individual and cumulative influence on the association between C. difficile ribotype and severe disease. We then validated this influence using an independent data set. RESULTS A total of 34 severe CDI cases were identified among 310 independent cases of disease (11.0%). Eleven covariates, including C. difficile ribotype, were significant predictors of severe CDI in unadjusted analysis. However, the association between ribotypes 027 and 078 and severe CDI was not significant after adjustment for any of the other covariates. After full adjustment, severe cases were significantly predicted only by patients' white blood cell count and albumin level. This result was supported by analysis of a validation data set containing 433 independent CDI cases (45 severe cases; 10.4%). CONCLUSIONS Ribotype is not a significant predictor of severe CDI when adjusted for the influence of any other variables separately or in combination. White blood cell count and albumin level are the most clinically relevant predictors of severe CDI cases.
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Affiliation(s)
- Seth T Walk
- Department of Internal Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
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Abstract
The intracellular pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae), described by Sir Arnold Theiler in 1910, is endemic worldwide in tropical and subtropical areas. Infection of cattle with A. marginale causes bovine anaplasmosis, a mild to severe hemolytic disease that results in considerable economic loss to both dairy and beef industries. Transmission of A. marginale to cattle occurs biologically by ticks and mechanically by biting flies and by blood-contaminated fomites. Both male ticks and cattle hosts become persistently infected with A. marginale and serve as reservoirs of infection. While erythrocytes are the major site of infection in cattle, A. marginale undergoes a complex developmental cycle in ticks that begins by infection of gut cells, and transmission to susceptible hosts occurs from salivary glands during feeding. Major surface proteins (MSPs) play a crucial role in the interaction of A. marginale with host cells, and include adhesion proteins and MSPs from multigene families that undergo antigenic change and selection in cattle, thus contributing to maintenance of persistent infections. Many geographic strains of A. marginale have been identified worldwide, which vary in genotype, antigenic composition, morphology and infectivity for ticks. Isolates of A. marginale may be maintained by independent transmission events and a mechanism of infection/exclusion in cattle and ticks. The increasing numbers of A. marginale genotypes identified in some geographic regions most likely resulted from intensive cattle movement. However, concurrent A. marginale strain infections in cattle was reported, but these strains were more distantly related. Phylogenetic studies of selected geographic isolates of A. marginale, using msp4 and msp1alpha, provided information about the biogeography and evolution of A. marginale, and msp1alpha genotypes appear to have evolved under positive selection pressure. Live and killed vaccines have been used for control of anaplasmosis and both types of vaccines have advantages and disadvantages. Vaccines have effectively prevented clinical anaplasmosis in cattle but have failed to block A. marginale infection. Vaccines are needed that can prevent clinical disease and, simultaneously, prevent infection in cattle and ticks, thus eliminating these hosts as reservoirs of infection. Advances in genomics, proteomics, immunology and biochemical and molecular technologies during the last decade have been applied to research on A. marginale and related organisms, and the recent development of a cell culture system for A. marginale has provided a format for studying the pathogen/tick interface. Recent advancements and new research methodologies should provide additional opportunities for development of new strategies for control and prevention of bovine anaplasmosis.
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Affiliation(s)
- Katherine M Kocan
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078-2007, USA.
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Schaefer JJ, Kahn J, Needham GR, Rikihisa Y, Ewing SA, Stich RW. Antibiotic clearance of Ehrlichia canis from dogs infected by intravenous inoculation of carrier blood. Ann N Y Acad Sci 2009; 1149:263-9. [PMID: 19120226 DOI: 10.1196/annals.1428.087] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ehrlichia canis is the etiologic agent of canine monocytic ehrlichiosis (CME) and is a useful model for zoonotic tick-borne pathogens, many of which infect dogs. The purpose of this study was to evaluate rifampin and doxycycline regimens for clearance of E. canis infections in addition to alleviation of CME. Beagles were infected with E. canis by intravenous inoculation with carrier blood and treated with either rifampin or doxycycline after the acute phase of CME. Improved hematological values demonstrated that both treatments effectively relieved signs of the disease. Peripheral blood from all dogs became PCR negative after antibiotic treatment, suggesting that these infections were eliminated and that rifampin is an effective alternative chemotherapeutic agent for treatment of CME.
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Affiliation(s)
- John J Schaefer
- Department of Veterinary Preventive Medicine, Ohio State University, Columbus, Ohio, 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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Schaefer JJ, Needham GR, Bremer WG, Rikihisa Y, Ewing SA, Stich RW. Tick acquisition of Ehrlichia canis from dogs treated with doxycycline hyclate. Antimicrob Agents Chemother 2007; 51:3394-6. [PMID: 17606682 PMCID: PMC2043173 DOI: 10.1128/aac.00358-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Doxycycline generally alleviates clinical monocytic ehrlichiosis, but its efficacy in the control of monocytotropic ehrlichial pathogens requires further investigation. In this study, Ehrlichia canis was detected in dogs treated with doxycycline for 14 days and in ticks fed on these dogs, suggesting that treated dogs can remain reservoirs for E. canis.
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Affiliation(s)
- John J Schaefer
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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10
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Forlano MD, Teixeira KRS, Scofield A, Elisei C, Yotoko KSC, Fernandes KR, Linhares GFC, Ewing SA, Massard CL. Molecular characterization of Hepatozoon sp. from Brazilian dogs and its phylogenetic relationship with other Hepatozoon spp. Vet Parasitol 2006; 145:21-30. [PMID: 17134837 DOI: 10.1016/j.vetpar.2006.10.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 10/21/2006] [Accepted: 10/27/2006] [Indexed: 11/21/2022]
Abstract
To characterize phylogenetically the species which causes canine hepatozoonosis at two rural areas of Rio de Janeiro State, Brazil, we used universal or Hepatozoon spp. primer sets for the 18S SSU rRNA coding region. DNA extracts were obtained from blood samples of thirteen dogs naturally infected, from four experimentally infected, and from five puppies infected by vertical transmission from a dam, that was experimentally infected. DNA of sporozoites of Hepatozoon americanum was used as positive control. The amplification of DNA extracts from blood of dogs infected with sporozoites of Hepatozoon spp. was observed in the presence of primers to 18S SSU rRNA gene of Hepatozoon spp., whereas DNA of H. americanum sporozoites was amplified in the presence of either universal or Hepatozoon spp.-specific primer sets; the amplified products were approximately 600bp in size. Cloned PCR products obtained from DNA extracts of blood from two dogs experimentally infected with Hepatozoon sp. were sequenced. The consensus sequence, derived from six sequence data sets, were blasted against sequences of 18S SSU rRNA of Hepatozoon spp. available at GenBank and aligned to homologous sequences to perform the phylogenetic analysis. This analysis clearly showed that our sequence clustered, independently of H. americanum sequences, within a group comprising other Hepatozoon canis sequences. Our results confirmed the hypothesis that the agent causing hepatozoonosis in the areas studied in Brazil is H. canis, supporting previous reports that were based on morphological and morphometric analyses.
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Affiliation(s)
- M D Forlano
- Decanato de Ciencias Veterinarias, Departamento de Salud Pública, Area de Parasitologia Veterinaria, Nucleo Dr Hector Ochoa Zuleta, Universidad Centroccidental Lisandro Alvarado UCLA, Cabudare, Barquisimeto, Lara, Venezuela
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11
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Cummings CA, Panciera RJ, Kocan KM, Mathew JS, Ewing SA. Characterization of stages of Hepatozoon americanum and of parasitized canine host cells. Vet Pathol 2006; 42:788-96. [PMID: 16301575 DOI: 10.1354/vp.42-6-788] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
American canine hepatozoonosis is caused by Hepatozoon americanum, a protozoan parasite, the definitive host of which is the tick, Amblyomma maculatum. Infection of the dog follows ingestion of ticks that harbor sporulated H. americanum oocysts. Following penetration of the intestinal mucosa, sporozoites are disseminated systemically and give rise to extensive asexual multiplication in cells located predominantly in striated muscle. The parasitized canine cells in "onion skin" cysts and in granulomas situated within skeletal muscle, as well as those in peripheral blood leukocytes (PBL), were identified as macrophages by use of fine structure morphology and/or immunohistochemical reactivity with macrophage markers. Additionally, two basic morphologic forms of the parasite were observed in macrophages of granulomas and PBLs. The forms were presumptively identified as merozoites and gamonts. The presence of a "tail" in some gamonts in PBLs indicated differentiation toward microgametes. Recognition of merozoites in PBLs supports the contention that hematogenously redistributed merozoites initiate repeated asexual cycles and could explain persistence of infection for long periods in the vertebrate host. Failure to clearly demonstrate a host cell membrane defining a parasitophorous vacuole may indicate that the parasite actively penetrates the host cell membrane rather than being engulfed by the host cell, as is characteristic of some protozoans.
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Affiliation(s)
- C A Cummings
- Department of Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
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12
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Forlano M, Scofield A, Elisei C, Fernandes KR, Ewing SA, Massard CL. Diagnosis of Hepatozoon spp. in Amblyomma ovale and its experimental transmission in domestic dogs in Brazil. Vet Parasitol 2005; 134:1-7. [PMID: 16081219 DOI: 10.1016/j.vetpar.2005.05.066] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 03/17/2005] [Accepted: 05/25/2005] [Indexed: 11/17/2022]
Abstract
Transmission of Hepatozoon spp. to dogs was investigated using four species of ixodid ticks: Rhipicephalus sanguineus, Amblyomma aureolatum, Amblyomma ovale and Amblyomma cajennense. We collected completely or partially engorged adult ticks of these species from dogs that were naturally infested and positive for Hepatozoon spp. We selected some of these ixodids and inoculated them orally in four negative dogs. The other ticks were dissected and examined for oocysts. Of all dogs inoculated orally with R. sanguineus, A. aureolatum, A. cajennense and A. ovale, only the animal that received the macerate of A. ovale was positive; evidence (gametocytes in peripheral blood) of infection was found 63 days after inoculation. Among all dissected ticks, we found only two oocysts; these were similar to those of Hepatozoon canis, and both were recovered from a single A. ovale specimen. We inoculated sporozoites recovered from the oocysts intraperitoneally into a Hepatozoon spp. negative dog, and circulating gametocytes were detected 84 days later. Our study demonstrated that A. ovale can be a vector of Hepatozoon spp. in Brazil.
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Affiliation(s)
- M Forlano
- Departamento de Parasitologia Animal, Faculdade de Medicina Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil.
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Reichard MV, Kocan AA, Van Den Bussche RA, Barker RW, Wyckoff JH, Ewing SA. SEQUENCE VARIATION OF THE RIBOSOMAL DNA SECOND INTERNAL TRANSCRIBED SPACER REGION IN TWO SPATIALLY DISTINCT POPULATIONS OF AMBLYOMMA AMERICANUM (L.) (ACARI: IXODIDAE). J Parasitol 2005; 91:260-3. [PMID: 15986597 DOI: 10.1645/ge-292r1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Sequence analysis of the ribosomal DNA second internal transcribed spacer (ITS 2) region in 2 spatially distinct populations of Amblyomma americanum (L.) revealed intraspecific variation. Nucleotide sequences from multiple DNA extractions and several polymerase chain reaction amplifications of eggs from mixed-parentage samples from both populations of ticks revealed that 12 of 1,145 (1.0%) sites varied. Three of the 12 sites of variation were distinct between the 2 A. americanum populations, which corresponded to a rate of 0.26%. Phylogenetic analysis based on ITS 2 sequences provided strong support (i.e., bootstrap value of 80%) that wild A. americanum clustered into a distinguishable group separate from those derived from colony ticks.
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Affiliation(s)
- M V Reichard
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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Barker RW, Kocan AA, Ewing SA, Wettemann RP, Payton ME. Occurrence of the Gulf Coast tick (Acari: Ixodidae) on wild and domestic mammals in north-central Oklahoma. J Med Entomol 2004; 41:170-178. [PMID: 15061275 DOI: 10.1603/0022-2585-41.2.170] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Parasitic life stages of Amblyomma maculatum Koch were collected from domestic cattle and several species of wild mammals during a 3.5-yr study (May 1998-October 2001) in north-central Oklahoma. Adult ticks were the predominant life stage collected from cattle, white-tailed deer, coyotes, and raccoons, whereas only immature ticks were collected from cotton rats and white-footed mice. The prevalence of adult A. maculatum on white-tailed deer (n = 15) examined in June, July, and August 1998 was 80, 100, 100%, respectively. The prevalence of adult A. maculatum on cattle (n = 84) ranged from 52% in February 1999 to 100% in May 1999. The prevalence of adult A. maculatum on coyotes (n = 16) was 100% in April 1998 and 43% on coyotes (n = 7) examined in January 2001. The prevalence of adult A. maculatum on raccoons (n = 23) examined during May, June, and July 1999 was 13%. No A. maculatum of any life stage were recovered from opossums (n = 7). Nine hundred forty-five rodents were trapped over 294 trap-nights; prevalence of A. maculatum larvae and nymphs on cotton rats (n = 395) was 34 and 15%, respectively, whereas on white-footed mice (n = 517), prevalence was 1.5 and 1.4%, respectively. No A. maculatum were recovered from pack rats (n = 33). There were significant differences (P = 0.0001) in larval infestation prevalence between cotton rats and white-footed mice in the spring, summer, and fall and for nymphs in the spring and summer. Results of A. maculatum parasitism and seasonal occurrence on hosts in this study are compared with previous research conducted in Oklahoma and with collection records of A. maculatum in the Entomology Museum at Oklahoma State University.
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Affiliation(s)
- R W Barker
- Department of Entomology and Plant Pathology, College of Agricultural Sciences and Natural Resources, Oklahoma State University, Stillwater, OK 74078, USA.
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Abstract
American canine hepatozoonosis (ACH) is a tick-borne disease that is spreading in the southeastern and south-central United States. Characterized by marked leukocytosis and periosteal bone proliferation, ACH is very debilitating and often fatal. Dogs acquire infection by ingesting nymphal or adult Gulf Coast ticks (Amblyomma maculatum) that, in a previous life stage, ingested the parasite in a blood meal taken from some vertebrate intermediate host. ACH is caused by the apicomplexan Hepatozoon americanum and has been differentiated from Old World canine hepatozoonosis caused by H. canis. Unlike H. canis, which is transmitted by the ubiquitous brown dog tick (Rhipicephalus sanguineus), H. americanum is essentially an accidental parasite of dogs, for which Gulf Coast ticks are not favored hosts. The geographic portrait of the disease parallels the known distribution of the Gulf Coast tick, which has expanded in recent years. Thus, the endemic cycle of H. americanum involves A. maculatum as definitive host and some vertebrate intermediate host(s) yet to be identified. Although coyotes (Canis latrans) are known to be infected, it is not known how important this host is in maintaining the endemic cycle. This review covers the biology of the parasite and of the tick that transmits it and contrasts ACH with classical canine hepatozoonosis. Clinical aspects of the disease are discussed, including diagnosis and treatment, and puzzling epidemiologic issues are examined. Brief consideration is given to the potential for ACH to be used as a model for study of angiogenesis and of hypertrophic osteoarthropathy.
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Affiliation(s)
- S A Ewing
- Department of Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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16
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Ewing SA, Panciera RJ. The biology and control of ticks infesting dogs and cats. Vet Ther 2004; 5:236-7; author reply 237. [PMID: 15726741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
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Abstract
To determine the persistence of Hepatozoon americanum in a naturally infected dog, skeletal muscle biopsies were performed at approximately 6-mo intervals over a period of 5.5 yr, and the samples were examined for presence of lesions of American canine hepatozoonosis (ACH). Nymphal Amblyomma maculatum (Gulf Coast tick) were allowed to feed to repletion on the dog periodically over the 5.5-yr period, and adult ticks were dissected and examined for presence of H. americanum oocysts. With 3 exceptions, the biopsied muscle contained lesions characteristic of ACH; no evidence of infection was found at 36, 54, and 67 mo after the original diagnosis. In every instance, nymphal Gulf Coast ticks became infected, indicating that dogs naturally infected with H. americanum can remain infectious for Gulf Coast ticks for at least 5.5 yr. Skeletal muscle biopsy is a reasonably reliable method of determining whether dogs are infected with the parasite. Xenodiagnosis using nymphal Gulf Coast ticks is an even more sensitive method, but the procedure is practicable only experimentally. Design of prevention and control measures for ACH must take into account knowledge that the parasite can survive in dogs, and presumably other vertebrate host(s), for long periods. Preventing ingestion of Gulf Coast ticks is an effective control measure.
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Affiliation(s)
- S A Ewing
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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18
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Abstract
American canine hepatozoonosis is an emerging, tick-transmitted infection of domestic dogs caused by a recently recognized species of apicomplexan parasite, Hepatozoon americanum. The known definitive host of the protozoan is the Gulf Coast tick, Amblyomma maculatum. Presently recognized intermediate hosts include the domestic dog and the coyote, Canis latrans. Laboratory-reared larval or nymphal A. maculatum can be infected readily by feeding to repletion on a parasitemic intermediate host; sporogony requires 35-40 days. Transmission of infection to the dog has been produced experimentally by oral administration of mature oocysts or oocyst-containing ticks. Canine disease follows experimental exposure in 4-6 weeks and is characterized by systemic illness, extreme neutrophilic leukocytosis, muscle and bone pain, and proliferation of periosteal bone. Histopathological findings include multifocal skeletal and cardiac myositis associated with escape of mature merozoites from within the host-cell environment. There is also rapid onset of periosteal activation and osteogenesis and, less frequently, glomerulopathy and amyloidosis. Sequential stages of development of H. americanum in both the dog and the tick have been elucidated. Gamonts potentially infectious to ticks have been observed in peripheral blood leukocytes of the dog in as few as 28 days after exposure to oocysts. Young coyotes experimentally exposed to a canine strain of H. americanum acquired disease indistinguishable from that of similarly exposed young dogs.
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Affiliation(s)
- R J Panciera
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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19
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Abstract
American canine hepatozoonosis (ACH) caused by Hepatozoon americanum Vincent-Johnson, Macintire, Lindsay, Lenz, Baneth, and Shkap is an emerging, often fatal, tick-borne protozoal disease of dogs in the United States of America. Dogs acquire infection by ingesting ticks that contain oocysts. To understand the invertebrate (definitive) host range of H. americanum, experiments were carried out using four ixodids, Rhipicephalus sanguineus (Latreille), Dermacentor variabilis Say, Amblyomma americanum (L.), and Amblyomma maculatum Koch. Laboratory-reared nymphal ticks were fed on dogs that were either naturally or experimentally infected with H. americanum; when these ticks molted to the adult stage they were either fed to susceptible dogs or were dissected and examined for the presence of oocysts. Mature H. americanum oocysts were found in >90% of A. maculatum (both males and females), whereas oocysts were not found in any of the other three species. These results confirm that A. maculatum is an excellent host and vector for H. americanum and also suggest that this apicomplexan may have a narrow invertebrate host range, at least among ixodid ticks that are likely candidate vectors in the United States.
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Affiliation(s)
- S A Ewing
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA.
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Chenoweth JL, Ewing SA, Bird JF. Procedures for ensuring community involvement in multijurisdictional river basins: a comparison of the Murray-Darling and Mekong river basins. Environ Manage 2002; 29:497-509. [PMID: 12071500 DOI: 10.1007/s00267-001-0029-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Community involvement is fundamental to the management of multijurisdictional river basins but, in practice, is very difficult to achieve. The Murray-Darling basin, in Australia, and the Mekong River basin in Southeast Asia are both cooperatively managed multijurisdictional river basins where the management authorities have expressed an aim of community involvement. In the Murray-Darling basin vigorous efforts have promoted a culture of community consultation throughout each of the state jurisdictions involved, although true participation has not necessarily been achieved. In the Mekong basin the community is much more diverse and the successes so far have been largely at the local level, involving action in subsections of the basin. These case studies suggest that community involvement in the form of community consultation across large multijurisdictional river basins is achievable, but more comprehensive participation is not necessarily possible.
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Stich RW, Rikihisa Y, Ewing SA, Needham GR, Grover DL, Jittapalapong S. Detection of Ehrlichia canis in canine carrier blood and in individual experimentally infected ticks with a p30-based PCR assay. J Clin Microbiol 2002; 40:540-6. [PMID: 11825969 PMCID: PMC153401 DOI: 10.1128/jcm.40.2.540-546.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Detection of vector-borne pathogens is necessary for investigation of their association with vertebrate and invertebrate hosts. The ability to detect Ehrlichia spp. within individual experimentally infected ticks would be valuable for studies to evaluate the relative competence of different vector species and transmission scenarios. The purpose of this study was to develop a sensitive PCR assay based on oligonucleotide sequences from the unique Ehrlichia canis gene, p30, to facilitate studies that require monitoring this pathogen in canine and tick hosts during experimental transmission. Homologous sequences for Ehrlichia chaffeensis p28 were compared to sequences of primers derived from a sequence conserved among E. canis isolates. Criteria for primer selection included annealing scores, identity of the primers to homologous E. chaffeensis sequences, and the availability of similarly optimal primers that were nested within the target template sequence. The p30-based assay was at least 100-fold more sensitive than a previously reported nested 16S ribosomal DNA (rDNA)-based assay and did not amplify the 200-bp target amplicon from E. chaffeensis, the human granulocytic ehrlichiosis agent, or Ehrlichia muris DNA. The assay was used to detect E. canis in canine carrier blood and in experimentally infected Rhipicephalus sanguineus ticks. Optimized procedures for preparing tissues from these hosts for PCR assay are described. Our results indicated that this p30-based PCR assay will be useful for experimental investigations, that it has potential as a routine test, and that this approach to PCR assay design may be applicable to other pathogens that occur at low levels in affected hosts.
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Affiliation(s)
- Roger W Stich
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio 43210-1092, USA.
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22
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Ewing SA, DuBois JG, Mathew JS, Panciera RJ. Larval Gulf Coast ticks (Amblyomma maculatum) [Acari: Ixodidae] as host for Hepatozoon americanum [Apicomplexa: Adeleorina]. Vet Parasitol 2002; 103:43-51. [PMID: 11750999 DOI: 10.1016/s0304-4017(01)00572-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Laboratory-reared larval Gulf Coast ticks (GCTs) (Amblyomma maculatum) were exposed experimentally and found to acquire Hepatozoon americanum infection while feeding on parasitemic dogs. These ticks supported gamogonic and sporogonic development of the apicomplexan, and oocysts from newly molted nymphs were infectious for a dog. Other nymphs from this cohort that were allowed to feed on a blood-parasite naive sheep molted normally; the resulting adult ticks contained oocysts that were infectious for another dog. Merogonic development of H. americanum in the dogs and the resulting lesions/disease appeared similar, irrespective of whether infectious oocysts were derived from nymphal or adult ticks that acquired infection as larvae. In the system previously known, nymphal ticks acquire infection and adults harbor infective oocysts, which vertebrate hosts ingest. Given that larval A. maculatum can acquire infection and nymphs can harbor viable oocysts as demonstrated by this study, the potential variety of vertebrate hosts that can alternate with GCTs in maintaining an endemic cycle is considerably expanded.
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Affiliation(s)
- S A Ewing
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-2006, USA
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23
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Dawson JE, Paddock CD, Warner CK, Greer PW, Bartlett JH, Ewing SA, Munderloh UG, Zaki SR. Tissue diagnosis of Ehrlichia chaffeensis in patients with fatal ehrlichiosis by use of immunohistochemistry, in situ hybridization, and polymerase chain reaction. Am J Trop Med Hyg 2001; 65:603-9. [PMID: 11716122 DOI: 10.4269/ajtmh.2001.65.603] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In the United States, human ehrlichiosis is a complex of emerging tick-borne diseases caused by 3 distinct Ehrlichia species: Ehrlichia chaffeensis, Ehrlichia ewingii, and the human granulocytotropic ehrlichiosis agent. Ehrlichioses are characterized by a mild to severe illness, and approximately 4% of cases are fatal. Because these obligate intracellular bacteria are difficult to resolve with routine histologic techniques, their distribution in tissues has not been well described. To facilitate the visualization and detection of ehrlichiae, immunohistochemistry (IHC), in situ hybridization (ISH), and polymerase chain reaction (PCR) assays were developed by use of tissues from 4 fatal cases of E. chaffeensis infection. Evidence of E. chaffeensis via IHC, ISH, and PCR was documented in all 4 cases. Abundant immunostaining and in situ nucleic acid hybridization were observed in spleen and lymph node from all 4 patients. Significantly, in 2 of these patients, serologic evidence of infection was absent. Use of IHC, ISH, and PCR to visualize and detect Ehrlichia in tissues can facilitate diagnosis of ehrlichial infections.
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Affiliation(s)
- J E Dawson
- Infectious Disease Pathology Activity, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Panciera RJ, Mathew JS, Cummings CA, Duffy JC, Ewing SA, Kocan AA. Comparison of tissue stages of Hepatozoon americanum in the dog using immunohistochemical and routine histologic methods. Vet Pathol 2001; 38:422-6. [PMID: 11467476 DOI: 10.1354/vp.38-4-422] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
American canine hepatozoonosis is caused by Hepatozoon americanum, a recently described species of apicomplexan protozoan parasite. An immunohistochemical procedure using a polyclonal antibody to sporozoites of H. americanum clearly identified asexual stages of H. americanum in canine striated muscle. The method also detects hepatozoa present in naturally infected coyotes and raccoons and reacts with certain other apicomplexans. Use of this immunohistochemical procedure confirms the canine intermediate host-parasite relationships that were presumptively established using conventional histopathologic methods.
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Affiliation(s)
- R J Panciera
- Department of Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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25
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Abstract
Hepatozoon canis was first described from dogs in 1905 in India and Rhipicephalus sanguineus was identified as the vector. Dogs on the Texas Gulf Coast were recognized in 1978 to have hepatozoonosis, and it was thought that H. canis had entered the New World. Later, it was realized that American canine hepatozoonosis (ACH) is more debilitating than its Old World counterpart, often resulting in death. When the malady and parasite were characterized, a new species, H. americanum, was described, in 1997. Phylogenetic analysis, based on 18S rRNA gene sequence and classical taxonomic features, revealed that the two dog parasites are closely related. Amblyomma maculatum, the Gulf Coast tick (GCT), has been demonstrated to be an excellent vector; nymphal ticks were readily infected and oocysts from newly molted adults were uniformly infectious for dogs. The merogonic cycle of H. americanum in dogs and the sporogonic development in the invertebrate host have been described. ACH is diagnosed primarily by histologic examination of skeletal muscle. Curative therapy is not available, but anti-protozoal and anti-inflammatory drugs may prolong life. Naturally infected coyotes have been found in Oklahoma and Texas, and experimental infections have been produced in this canid. Additional effort is needed to determine the vertebrate host range of H. americanum and to define the enzootic cycle of which dogs have become a part; likewise, more work is required to determine whether larval GCTs can acquire infection and transmit it as nymphs.
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Affiliation(s)
- S A Ewing
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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26
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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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27
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Mathew JS, Saliki JT, Ewing SA, Lehenbauer TW, Panciera RJ, Malayer JR, Cummings CA, Kocan AA. An indirect enzyme-linked immunosorbent assay for diagnosis of American canine hepatozoonosis. J Vet Diagn Invest 2001; 13:17-21. [PMID: 11243356 DOI: 10.1177/104063870101300104] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
American canine hepatozoonosis (ACH), caused by Hepatozoon americanum, is an emerging tick-borne disease of dogs. An indirect enzyme-linked immunosorbent assay (ELISA) that should facilitate diagnosis of infection and study of the epidemiology of ACH has been developed using H. americanum sporozoites as antigen. Efficacy of the new test as a diagnostic tool was compared with that of skeletal muscle biopsy, the current gold standard for confirming H. americanum infection. Results show that the test is sensitive (93%) and specific (96%) and that it is as reliable as histopathologic examination of skeletal muscle for detecting infection. The ELISA would be suitable as a routine laboratory test for diagnosis of ACH.
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Affiliation(s)
- J S Mathew
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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28
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Mathew JS, Ewing SA, Malayer JR, Fox JC, Kocan KM. Efficacy of a modified polymerase chain reaction assay for detection of Ehrlichia canis infection. J Vet Diagn Invest 2000; 12:456-9. [PMID: 11021435 DOI: 10.1177/104063870001200512] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Detection of Ehrlichia canis in acutely infected and convalescent dogs is important for effective treatment and control. However, accurate detection has been difficult to achieve, in part because dogs that have been treated therapeutically often remain seropositive for extended periods. A new method, polymerase chain reaction (PCR) assay using biotinylated E. canis-specific primers (PCR-BP), was developed for detection of E. canis. Four dogs experimentally infected with E. canis by intravenous inoculation of whole blood from carrier dogs and 2 naturally infected convalescent carriers were used to compare the specificity and sensitivity of the new method with that of microscopy/blood smear evaluation, serologic test, and conventional PCR assay using E. canis-specific primers. In experimentally infected animals, infection was detected as early as 7 days post-exposure using PCR-BP. Although the 2 naturally infected dogs were positive by serologic test and PCR-BP, both were negative by conventional PCR. Results suggest that the new method is a sensitive assay for detection of E. canis infection. In addition, results were obtained more rapidly than with other PCR-based assays.
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Affiliation(s)
- J S Mathew
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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29
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Kocan AA, Ewing SA, Stallknecht D, Murphy GL, Little S, Whitworth LC, Barker RW. Attempted transmission of Ehrlichia chaffeensis among white-tailed deer by Amblyomma maculatum. J Wildl Dis 2000; 36:592-4. [PMID: 10941753 DOI: 10.7589/0090-3558-36.3.592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A deer was needle-exposed intravenously to Ehrlichia chaffeensis (Rickettsiales: Ehrlichieae) in canine macrophage (DH82) cells and 7 days later was infested with laboratory-reared Amblyomma maculatum (Koch) (Acari:Ixodidae) nymphs for acquisition feeding. After molting, the adult ticks were allowed to feed on a naive deer. The organism was reisolated from the needle-exposed deer by cell culture and E. chaffeensis DNA was detected in the deer's blood by PCR. Similar isolation/recovery techniques were used for the tick-exposed deer and no evidence of infection was found. Although these findings must be considered as preliminary owing to inadequate controls, the data suggest that A. maculatum is probably not a suitable vector for E. chaffeensis.
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Affiliation(s)
- A A Kocan
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA.
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30
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Abstract
Canine hepatozoonosis, caused by Hepatozoon americanum, is an emerging tick-borne disease of dogs in North America. In addition to the skeletal and cardiac myositis that are prominent features of the disease, there is disseminated periosteal bone proliferation in most dogs that manifest clinical disease. Each of six experimentally infected animals (four dogs and two coyotes) and seven of eight naturally infected dogs had gross or histopathologic osteoproliferative lesions. Experimental animals were 6-9 months of age when exposed. Naturally infected dogs were 8 months to 11 years old when subjected to necropsy. Lesions occurred primarily on the diaphysis of the more proximal long bones of the limbs; however, flat and irregular bones were frequently involved. Lesions involving metacarpals, metatarsals, and digits were infrequent. The earliest observed periosteal lesions were in an experimentally infected dog 32 days after exposure to sporulated oocysts of H. americanum. There were hypertrophy and hyperplasia of osteoprogenitor cells, and osteoblasts appeared in the cellular zone of the periosteum. Spicules of woven bone oriented perpendicularly to bone cortex followed. Later yet, periosteal new bone was remodeled and tended to become oriented parallel to the cortical bone. Horizontally oriented zones of remodeled, condensed bone sometimes occurred in multiple layers on the original cortex, forming "pseudocortices." The osseous lesions of American canine hepatozoonosis, with few variations, are remarkably similar to those of hypertrophic osteopathy in domestic dogs and other mammalian species, including humans.
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Affiliation(s)
- R J Panciera
- Department of Veterinary Anatomy, Pathology and Pharmacology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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31
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Mathew JS, Van Den Bussche RA, Ewing SA, Malayer JR, Latha BR, Panciera RJ. Phylogenetic relationships of Hepatozoon (Apicomplexa: Adeleorina) based on molecular, morphologic, and life-cycle characters. J Parasitol 2000; 86:366-72. [PMID: 10780559 DOI: 10.1645/0022-3395(2000)086[0366:prohaa]2.0.co;2] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
To evaluate higher-level affinities of Hepatozoon species within Apicomplexa, we sequenced the 18S rRNA gene from 2 parasites (Hepatozoon americanum and Hepatozoon canis) of dogs and 1 (Hepatozoon catesbianae) of bullfrogs. Sequences from other apicomplexans among the Sarcocystiidae, Eimeriidae, Theileriidae, Plasmodiidae, Cryptosporiidae, and Babesiidae, a Perkinsus species and 2 dinoflagellates were obtained from GenBank. Phylogenetic analysis indicated that Plasmodium, Cryptosporidium, and Hepatozoon form a monophyletic group distinct from representatives of other apicomplexan families. Although equivocal, our analysis indicated that Plasmodium and Cryptosporidium are sister taxa and that Hepatozoon is basal to them. To evaluate phylogenetic affinities among H. americanum, H. canis, and other species of Hepatozoon, we examined 18 morphologic and life-cycle features of 13 species currently assigned to Hepatozoon. This analysis indicates paraphyly of Hepatozoon (as currently arranged) because Hepatozoon lygosomarum was found most closely related to Hemolivia mauritanicum. These results, combined with results of previous studies, support elevating Hepatozoon to familial level (Hepatozoidae) as originally suggested by Wenyon in 1926. Both DNA sequence data and morphologic and life-cycle characters support a sister-group relationship between H. americanum and H. canis.
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Affiliation(s)
- J S Mathew
- Department of Infectious Diseases and Physiology, Oklahoma State University, Stillwater 74078, USA
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32
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Abstract
A nested polymerase chain reaction assay was used to determine the presence of Ehrlichia chaffeensis, E. canis, and E. ewingii DNA in blood samples of free-ranging coyotes from central and northcentral Oklahoma. Of the 21 coyotes examined, 15 (71%) were positive for E. chaffeensis DNA; none was positive for E. canis or E. ewingii. Results suggest that E. chaffeensis infections are common in free-ranging coyotes in Oklahoma and that these wild canids could play a role in the epidemiology of human monocytotropic ehrlichiosis.
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Affiliation(s)
- A A Kocan
- Oklahoma State University, Stillwater, Oklahoma 74078, USA. aak4453@
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33
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Kocan AA, Cummings CA, Panciera RJ, Mathew JS, Ewing SA, Barker RW. Naturally occurring and experimentally transmitted Hepatozoon americanum in coyotes from Oklahoma. J Wildl Dis 2000; 36:149-53. [PMID: 10682757 DOI: 10.7589/0090-3558-36.1.149] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Twenty free-ranging coyotes (Canis latrans) in Oklahoma (USA) were examined for the presence of naturally occurring infections with Hepatozoon americanum and to determine if bone lesions attributable to H. americanum were present. Although eight of the 20 free-ranging coyotes were found to be naturally infected with H. americanum, no bone lesions were detected. In addition, two coyote pups were exposed to H. americanum oocysts collected from experimentally infected ticks and the course of the resulting infection was followed. Both experimentally infected coyotes developed hepatozoonosis detectable by specific muscle lesions beginning 4 wk after exposure. Bone lesions were detected grossly and histologically at necropsy. Histologic evidence of periosteal bone proliferation ranged from segmental areas of plump hypercellularity and thickening of the periosteum, with minor degrees of osteogenesis, to extensive proliferation of woven bone and periosteal hypercellularity and thickening. Nymphal Amblyomma maculatum that fed on one of the experimentally infected coyote pups became infected and mature H. americanum oocysts were recovered when the ticks molted to adults. These results demonstrate that coyotes in some parts of Oklahoma are naturally infected with H. americanum, that experimentally infected coyotes can develop clinical disease, including characteristic bone lesions, and that A. maculatum nymphs can acquire infections by feeding on them.
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Affiliation(s)
- A A Kocan
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA.
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34
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Mathew JS, Ewing SA, Panciera RJ, Kocan KM. Sporogonic development of Hepatozoon americanum (Apicomplexa) in its definitive host, Amblyomma maculatum (Acarina). J Parasitol 1999; 85:1023-31. [PMID: 10647032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Light microscopic observations of the sporogonic development of Hepatozoon americanum are described in its acarine host, Amblyomma maculatum. Laboratory-reared nymphal ticks were fed on 2 dogs infected with H. americanum. Nymphal ticks were sampled daily, starting 3 days after being placed on a parasitemic dog, until 18 days after infestation (PI), and then every 3 or 4 days until replete nymphs molted. Ticks were examined as unstained wet mounts and hematoxylin-eosin-stained paraffin sections. Gametes were found within the gut cells of nymphs 4 and 6 days PI. Although differentiation of gamonts into gametes was not detected, syngamy and sporogony were observed. Sporogony appears to occur wholly within tick gut cells, followed by release of mature oocysts into the hemocoel. The earliest evidence of sporoblast formation was observed 23 days PI and of sporozoite formation, 10 days later. Mature oocysts were first found 42 days PI in newly molted adult ticks. Most adult ticks (>98%) that were dissected contained mature oocysts. Oocysts were multisporocystic, and sporocysts contained a variable number of sporozoites. Oocysts in various stages of development were often seen within the same tick, and the number of mature oocysts ranged from 4 to 573.
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Affiliation(s)
- J S Mathew
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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35
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Panciera RJ, Ewing SA, Mathew JS, Lehenbauer TW, Cummings CA, Woods JP. Canine hepatozoonosis: comparison of lesions and parasites in skeletal muscle of dogs experimentally or naturally infected with Hepatozoon americanum. Vet Parasitol 1999; 82:261-72. [PMID: 10384901 DOI: 10.1016/s0304-4017(99)00029-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We report previously undescribed, early lesions in skeletal muscle of dogs experimentally infected with Hepatozoon americanum by ingestion of laboratory-reared, infected Amblyomma maculatum. The earliest muscle lesion was recognized at the first interval of examination 3 weeks following exposure. The lesion consisted of a large, modified host cell whose cytoplasm frequently contained a demonstrable parasite. In skeletal muscle, the cell was consistently located between muscle fibers or in loose connective tissue adjacent to those fibers. Evidence suggesting that the parasite arrives in muscle and other tissue within the host cell cytoplasm is presented. Mucopolysaccharide encystment of the host cell, absent at this early stage, was acquired gradually and approached maximal development 26 weeks post exposure. Completion of the asexual cycle as evidenced by the presence of parasites entering vascular lumens within granulomas and also by the presence of gamonts in peripheral blood leukocytes, occurred within 28-32 days postexposure. Progression of the parasite cycle from meront to passage of zoites into vessel lumens of granulomas can occur in 11 or fewer days. The density with which parasitic lesions occur in one named skeletal muscle compared to other named muscles, although somewhat variable, was not significantly different in either experimentally induced or natural infections. The distribution of developmental stages of the parasite/lesion in four experimental infections (969 lesions) is compared with those in eight dogs with natural infections (557 lesions).
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Affiliation(s)
- R J Panciera
- Department of Anatomy, Pathology and Pharmacology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA
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36
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Abstract
Nine of 16 free-ranging coyotes (Canis latrans) from central Oklahoma (USA) had naturally acquired infections of Hepatozoon americanum. Infections were confirmed by recognition of tissue stages closely resembling H. americanum in skeletal and cardiac muscle. At the time coyotes were collected they were infested with a variety of ticks, including adult Gulf Coast ticks (Amblyomma maculatum). We propose that the high prevalence of H. americanum in this small sample of free-ranging coyotes and the ability of these same animals to harbor adult populations of A. maculatum is an important component of the epizootiology of canine hepatozoonosis in North America.
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Affiliation(s)
- A A Kocan
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA.
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37
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Mathew JS, Ewing SA, Panciera RJ, Woods JP. Experimental transmission of Hepatozoon americanum Vincent-Johnson et al., 1997 to dogs by the Gulf Coast tick, Amblyomma maculatum Koch. Vet Parasitol 1998; 80:1-14. [PMID: 9877066 DOI: 10.1016/s0304-4017(98)00189-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Experimental transmission of Hepatozoon americanum to dogs was attempted with four ixodid ticks, viz., Rhipicephalus sanguineus, Amblyomma americanum, Amblyomma maculatum and Dermacentor variabilis. Ticks that dogs ingested included some that were laboratory-reared and experimentally fed as nymphs on a dog with naturally occurring hepatozoonosis; other ticks were collected as replete or partially engorged larvae, nymphs and adults from dogs that had hepatozoonosis and natural infestations of ticks. Whole ticks used to expose susceptible dogs orally were partially dissected to help release oocysts. Among eight dogs exposed, only the three that were fed A. maculatum adults experimentally acquisition fed as nymphs became infected. Dogs developed elevated body temperature and other evidence of clinical disease starting 4 weeks after exposure. 'Cysts' typical of H. americanum were found in skeletal muscle when samples were first examined 5 weeks after dogs ingested ticks, and parasites were also observed in peripheral blood smears at approximately the same time. Our study demonstrates that A. maculatum nymphs can acquire H. americanum by feeding on a parasitemic dog and that transstadial transmission of the protozoan occurs, with dogs acquiring infection when they ingest newly molted adult ticks.
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Affiliation(s)
- J S Mathew
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA
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38
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Murphy GL, Ewing SA, Whitworth LC, Fox JC, Kocan AA. A molecular and serologic survey of Ehrlichia canis, E. chaffeensis, and E. ewingii in dogs and ticks from Oklahoma. Vet Parasitol 1998; 79:325-39. [PMID: 9831955 DOI: 10.1016/s0304-4017(98)00179-4] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Polymerase chain reaction and Southern hybridization were used to survey for the presence of Ehrlichia canis, Ehrlichia chaffeensis, and Ehrlichia ewingii in blood samples of 65 dogs that harbored ticks from northcentral and northeastern Oklahoma. Dog blood samples were also examined for antibodies against E. canis and E. chaffeensis, using an immunofluorescent antibody test. Ten of 65 dogs (15.4%) examined were positive for Ehrlichia spp. by PCR. Four (6.2%) were positive for E. ewingii, 2 (3.1%) for E. canis, and 4 (6.2%) for E. chaffeensis. Seven dogs (10.8%) were seropositive for E. canis or E. chaffeensis. Ticks collected from PCR-positive dogs were examined by PCR for the presence of Ehrlichia DNA. Several groups of ticks were PCR-positive for E. ewingii or E. canis. E. canis was detected in Rhipicephalus sanguineus, which is considered the major vector for that organism. E. ewingii was detected in a larger variety of ticks, including the only known vector Amblyomma americanum, as well as in Dermacentor variabilis and R. sanguineus. Results suggest that Ehrlichia spp. which are canine and human pathogens circulate in dogs in Oklahoma and in several tick species that feed on dogs.
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Affiliation(s)
- G L Murphy
- Department of Anatomy, Pathology, and Pharmacology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA.
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39
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Meinkoth JH, Ewing SA, Cowell RL, Dawson JE, Warner CK, Mathew JS, Bowles M, Thiessen AE, Panciera RJ, Fox C. Morphologic and molecular evidence of a dual species ehrlichial infection in a dog presenting with inflammatory central nervous system disease. J Vet Intern Med 1998; 12:389-93. [PMID: 9773417 DOI: 10.1111/j.1939-1676.1998.tb02140.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- J H Meinkoth
- Department of Anatomy, Pathology and Pharamacology, Oklahoma State University, Stillwater 74078, USA.
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40
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Panciera RJ, Ewing SA, Mathew JS, Cummings CA, Kocan AA, Breshears MA, Fox JC. Observations on tissue stages of Hepatozoon americanum in 19 naturally infected dogs. Vet Parasitol 1998; 78:265-76. [PMID: 9786627 DOI: 10.1016/s0304-4017(98)00142-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lesions and associated tissue stages of Hepatozoon americanum in 19 naturally infected dogs are described. Schizogony takes place in an unidentified host cell which, during the early stages of the asexual cycle, is contained within a broad, multilamellar mucopolysaccharide 'cyst.' Material forming the cyst appears to be host-derived. An intense inflammatory response follows rupture of the schizont and disintegration of the cyst wall. There is unusually intense angiogenesis associated with the resulting granulomatous inflammation initiated by the freed merozoites. Phagocytized zoites enter the canine circulatory system through the walls of these vessels. Evidence is presented that suggests a single infecting episode can cause prolonged (> or = 9 months) infection, and further, that infection is perpetuated by repeated asexual cycles. Parasites in peripheral blood leukocytes include both those with and without a visible nucleus.
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Affiliation(s)
- R J Panciera
- Department of Anatomy, Pathology and Pharmacology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA
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41
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Johnson EM, Ewing SA, Barker RW, Fox JC, Crow DW, Kocan KM. Experimental transmission of Ehrlichia canis (Rickettsiales: Ehrlichieae) by Dermacentor variabilis (Acari: Ixodidae). Vet Parasitol 1998; 74:277-88. [PMID: 9561712 DOI: 10.1016/s0304-4017(97)00073-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Four trials were conducted in which laboratory-reared Dermacentor variabilis nymphs were exposed to Ehrlichia canis by feeding on experimentally infected dogs as soon as classical morulae were detected in peripheral blood monocytes. After molting 25, 50 or 90 adult tick pairs were permitted to feed on 7 Ehrlichia-naive dogs. Transmission occurred in trials 1 (1/1 dog), 3 (1/1 dog) and 4 (2/2 dogs) but not in trial 2 (0/3 dogs), with 4 of 7 dogs becoming infected. Successful transstadial transmission was demonstrated by detection of morulae in peripheral blood lymphocytes and by seroconversion to Ehrlichia canis 30 d post-exposure. Incubation periods ranged between 17 and 22 days (mean = 19). Clinical signs, typical of ehrlichiosis, included mucopurulent ocular discharge, lymphadenopathy and malaise with accompanying pyrexia, leukopenia and thrombocytopenia. Pyrexia, thrombocytopenia and erythrophagocytosis and vacuolization of the cytoplasm of monocytic cells were observed 1-4 d prior to detection of morulae. This is the first demonstration that a tick other than Rhipicephalus sanguineus is capable of transstadial transmission of this important pathogen of dogs.
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Affiliation(s)
- E M Johnson
- Department of Infectious Diseases and Physiology, Stillwater, OK 74078, USA
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42
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Ewing SA, Dawson JE, Panciera RJ, Mathew JS, Pratt KW, Katavolos P, Telford SR. Dogs infected with a human granulocytotropic Ehrlichia spp. (Rickettsiales: Ehrlichieae). J Med Entomol 1997; 34:710-718. [PMID: 9439127 DOI: 10.1093/jmedent/34.6.710] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Dogs were found to be susceptible to human granulocytotropic Ehrlichia spp. Infection was produced through the bite of Ixodes scapularis Say (= dammini Spielman, Clifford, Piesman & Corwin) nymphs and adults that acquired infection while feeding as larvae on experimentally infected mice. Dogs were also infected by intravenous injection of mouse blood or dog blood from parasitemic donors. Parasites were demonstrable in neutrophils within 8 or 9 d after nymphs began feeding; prepatent periods were longer when infection was induced by adult tick feeding (18 d) or by transfusion of mouse blood (12 d). The shortest prepatent period observed was 5 d in a dog infected by transfusion of blood from a parasitemic dog. Infections in dogs were mild and apparently transient. Mild thrombocytopenia was the most commonly observed abnormality. Parasites could be detected by light microscopy during the acute phase of infection (4 or 5 d) and parasite DNA by polymerase chain reaction as early as 5 d after exposure but not at 6-9 d after morulae were first observed in neutrophils. Likewise, dog blood was infectious for mice at 2 d but not at 25 d, and for dogs at 3 d but not at 13 d after morulae were first observed in neutrophils. Seroconversion occurred as early as 11 d after onset of tick feeding and persisted until dogs were euthanatized. Gross and histopathologic lesions were similar to those observed in dogs with E. canis (Donatien & Lestoquard), E. chaffeensis Anderson, Dawson & Wilson, and E. ewingii Anderson, Greene, Jones & Dawson infections but were generally milder than any of these. The moderate enlargement of lymphoid organs observed grossly was reflected histologically as mild to moderate reactive hyperplasia, which was largely follicular (B cell).
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Affiliation(s)
- S A Ewing
- College of Veterinary Medicine, Oklahoma State University Stillwater 74078, USA
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Dawson JE, Warner CK, Ewing SA, Telford SR, Corstvet RE, Brennan R, Olson JG. Fingerprinting of Ehrlichia species by repetitive element polymerase chain reaction. Am J Trop Med Hyg 1997; 57:109-14. [PMID: 9242329 DOI: 10.4269/ajtmh.1997.57.109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To facilitate identification of ehrlichial pathogens, we developed a new technique based on fingerprints resulting from repetitive element polymerase chain reaction (rep-PCR). This technique uses consensus tRNA primers to generate amplification products that reflect distance polymorphisms between adjacent tRNA genes. Species-specific fingerprint patterns were obtained for seven Ehrlichia spp., as well as the unnamed causative agent of human granulocytotropic ehrlichiosis. Bands ranged in size from approximately 50 to 1,000 base pairs. Banding patterns varied depending on dilution of template DNA, with lower dilutions giving more complex banding patterns. These preliminary data indicate that repetitive-sequence-based PCR appears to be a useful technique for identifying ehrlichial organisms to the species, and perhaps the strain level. Compared with other conventional molecular-biologic methods, rep-PCR offers the advantages of ease of performance and rapid availability of results.
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Affiliation(s)
- J E Dawson
- Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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Affiliation(s)
- S A Ewing
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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Ewing SA, Dawson JE, Mathew JS, Barker RW, Pratt KW, Telford SR. Attempted transmission of human granulocytotropic Ehrlichia (HGE) by Amblyomma americanum and Amblyomma maculatum. Vet Parasitol 1997; 70:183-90. [PMID: 9195722 DOI: 10.1016/s0304-4017(96)01157-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Transstadial transmission of human granulocytotrophic Ehrlichia (HGE) was attempted in dogs using Amblyomma americanum (L.) and A. maculatum Koch, two species that, as adults, feed readily on human beings. Larvae and nymphs were acquisition-fed on a dog that was parasitemic with HGE. Two months later, following digestion of the blood meal and subsequent molting to nymphal or adult stage, these ticks were fed to repletion on HGE-naive dogs. None of the dogs developed clinical evidence of ehrlichiosis. Parasites were not observed in blood smears by light microscopy, HGE DNA was not detected by polymerase chain reaction, and none of the dogs seroconverted. Based on this trial, we conclude that, unlike E. chaffeensis, HGE is probably not transmitted from dog to dog by either A. americanum or A. maculatum.
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Affiliation(s)
- S A Ewing
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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Ewing SA, Panciera RJ, Kocan KM, Ge NL, Welsh RD, Olson RW, Barker RW, Rice LE. A winter outbreak of anaplasmosis in a nonendemic area of Oklahoma: a possible role for Dermacentor albipictus. J Vet Diagn Invest 1997; 9:206-8. [PMID: 9211245 DOI: 10.1177/104063879700900219] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- S A Ewing
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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Ge NL, Kocan KM, Ewing SA, Blouin EF, Edwards WL, Murphy GL, Dawson LJ. Use of a nonradioactive DNA probe for detection of Anaplasma marginale infection in field cattle: comparison with complement fixation serology and microscopic examination. J Vet Diagn Invest 1997; 9:39-43. [PMID: 9087923 DOI: 10.1177/104063879700900107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A sensitive Anaplasma marginale-specific 409-base pair DNA probe was developed in a previous study for detection of A. marginale infection in experimentally infected cattle with a test that employed slot-blot and in situ hybridization. To test the suitability of the probe to detect A. marginale in the blood of naturally infected carrier cattle, slot-blot hybridization was used to determine the infection rate of A. marginale in cattle from 3 geographic areas in Oklahoma. For comparison, blood samples from the same cattle were also examined by light microscopy and were tested by the complement fixation test. For the DNA hybridization assay, the probe was labeled with digoxigenin 11-dUTP by polymerase chain reaction (PCR). DNA was extracted from blood using the QIAamp blood kit and then applied to a nylon membrane and hybridized with the probe. The study herds consisted of 31 beef cows in Harper County, OK, and 42 and 70 dairy cows from Payne and Pittsburg counties, OK, respectively. In the 3 herds, 80.6%, 92.8%, and 57.1% of the cows were positive for A. marginale as assessed with the DNA hybridization assay. In contrast, only 25.8% and 2.86% were complement fixation positive in 2 herds, and no complement fixation positives were found in 1 herd. Uncountable parasitemia that was too low to accurately determine (< 0.01%) from 29.0%, 4.8%, and 11.4% of the samples, respectively, was demonstrated by microscopic examination. All samples positive by complement fixation and microscopic examination had positive probe reactions in the DNA hybridization assay. Therefore, the PCR-mediated nonradioactive DNA probe described here may be useful in epidemiologic investigations and in identification of carrier cattle. This assay could be adapted for use in diagnostic laboratories because it is sensitive, specific, nontoxic, quickly executed, and inexpensive.
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Affiliation(s)
- N L Ge
- College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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Mathew JS, Ewing SA, Murphy GL, Kocan KM, Corstvet RE, Fox JC. Characterization of a new isolate of Ehrlichia platys (Order Rickettsiales) using electron microscopy and polymerase chain reaction. Vet Parasitol 1997; 68:1-10. [PMID: 9066046 DOI: 10.1016/s0304-4017(96)01052-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A mixed-breed pup approximately 3 months old obtained in north central Oklahoma by the Laboratory Animal Resources Unit of Oklahoma State University presented with platelet inclusions. The dog developed severe thrombocytopenia (< 10,000 microliters-1) following the appearance of inclusions. Blood films were monitored daily and when about 75% of platelets had inclusions, samples were collected in EDTA and processed for electron microscopic (EM) studies and polymerase chain reaction (PCR). EM studies on glutaraldehyde-fixed buffy coat revealed rickettsia-like inclusions in numerous platelets. Serologic examination, using Ehrlichia platys antigen, showed high titre suggestive of E. platys infection. PCR primers derived from a highly variable region of the 16S rRNA gene sequence of E. platys were used to specifically amplify that region of the parasite's DNA. Sequencing of the PCR product obtained by general Ehrlichia primers showed one nucleotide difference from the published sequence for E. platys which suggests possible strain variation of this intracellular parasite. Our results indicate that PCR may be a useful tool in the diagnosis of E. platys infection and that, like other Ehrlichia spp., E. platys isolates may vary.
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Affiliation(s)
- J S Mathew
- Department of Infectious Diseases and Physiology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA
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Mathew JS, Ewing SA, Barker RW, Fox JC, Dawson JE, Warner CK, Murphy GL, Kocan KM. Attempted transmission of Ehrlichia canis by Rhipicephalus sanguineus after passage in cell culture. Am J Vet Res 1996; 57:1594-8. [PMID: 8915436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES To compare the transmissibility by the brown dog tick, Rhipicephalus sanguineus, of a recent isolate of Ehrlichia canis (Ebony) with that of another isolate (Oklahoma) that had been passaged in cell culture, and to assess the genetic similarity of the 2 isolates as reflected in the nucleotide (NT) sequence of 16S rDNA. ANIMALS 13 healthy dogs of various ages and breeds. PROCEDURE Larval and nymphal ticks were acquisition fed on acutely infected dogs, and, after molting, they were transmission fed as nymphs and adults, respectively, on Ehrlichia-naive dogs. All dogs were monitored daily by blood smear evaluation for evidence of parasitized leukocytes and by physical examination for clinical signs of ehrlichiosis. Serologic and hematologic values were measured weekly. Using a nested polymerase chain reaction, the 16S rDNA was amplified, and the NT sequence of the template DNA was determined. RESULTS The Ebony isolate of E canis was successfully transmitted to dogs by nymphal and adult ticks. In contrast, no ticks that fed on dogs harboring the cell-cultured isolate (Oklahoma) transmitted it to dogs. On the basis of 16S rDNA sequence, the 2 isolates were 99.9% similar, with only 1 NT difference. CONCLUSIONS These results reconfirm the vector potential of R sanguineus for E canis. Passage of the Oklahoma isolate of E canis in cell culture apparently adversely affected its transmissibility by ticks, raising the possibility that cell-cultured isolates of this rickettsia may lose their affinity for ticks. Determination of 16S rDNA sequence suggests minor strain variation within the species E canis.
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Affiliation(s)
- J S Mathew
- Department of Infectious Diseases, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA
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Katz JB, Barbet AF, Mahan SM, Kumbula D, Lockhart JM, Keel MK, Dawson JE, Olson JG, Ewing SA. A recombinant antigen from the heartwater agent (Cowdria ruminatium) reactive with antibodies in some southeastern United States white-tailed deer (Odocoileus virginianus), but not cattle, sera. J Wildl Dis 1996; 32:424-30. [PMID: 8827667 DOI: 10.7589/0090-3558-32.3.424] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recombinant baculovirus techniques were used to express the 260 amino acid carboxyterminal portion of the 32 kilodalton (kDa) major antigenic protein (MAP 1) of Cowdria ruminantium, the heartwater agent, as a fusion protein. The recombinant MAP 1 was fused to an aminoterminal independently antigenic octapeptide sequence (FLAG peptide). Recombinant MAP 1 was used as an immunoblotting antigen to evaluate numerous reference antisera against organisms of the tribe Ehrlichieae. Monoclonal and polyclonal C. ruminantium antibodies, monoclonal anti-FLAG ascites, and antisera to Ehrlichia canis and Ehrlichia chaffeensis reacted with this antigen. Twelve of 79 sera collected 1980 to 1992 from southeastern U.S. white-tailed deer (Odocoileus virginianus) were also unexpectedly immunoblot-positive to MAP 1. These 12 deer sera had, as a group, significantly (P < 0.01) greater anti-E. chaffeensis titers (previously determined) than the sera from MAP 1 immunoblot-negative deer living in the same areas. None of the 262 sera from cattle living in the same areas were immunoblot-positive to MAP 1. All of an additional 50 cervine sera from Michigan (USA), 72 bovine sera from northern U.S. cattle, and 72 sera from Puerto Rican cattle were also immunoblot-negative to MAP 1. Sera from African sheep which were falsely seropositive to authentic MAP 1 were also immunoblot-positive to the recombinant MAP 1. Unidentified Ehrlichia spp. capable of serologic crossreactivity with the heartwater agent appear to be present in some southeastern U.S. white-tailed deer but not cattle. These or related Ehrlichia spp. may also be found elsewhere in the world in non-cervine species.
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Affiliation(s)
- J B Katz
- Diagnostic Virology Laboratory, United States Department of Agriculture, Ames, Iowa 50010, USA
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