Susceptibility of white-tailed deer (Odocoileus virginianus) to infection with Ehrlichia chaffeensis, the etiologic agent of human ehrlichiosis

Dawson, Jacqueline E.; Stallknecht, David E.; Howerth, Elizabeth W.; Warner, Cynthia K.; Biggie, Kristine L.; Davidson, William R.; Lockhart, J. Mitchell; Nettles, Victor F.; Olson, James G.; Childs, James E.

doi:10.1128/jcm.32.11.2725-2728.1994

Cited by 183 publications

(98 citation statements)

References 7 publications

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“…(iii) Isolation and purification of DNA from the swabs. The following six standard protocols and three modifications of standard protocols were used and the results were compared: boiling of the swab for 20 min (10), the method of Dawson et al (4), the method of Schoolnik (18), the method of de Lamballerie et al (5), use of the QIAamp Tissue Kit and the QIAamp Blood Kit (both from QIAGEN GmbH, Hilden, Germany), a combination of lysozyme treatment and boiling, a combination of lysozyme treatment and the method of Dawson et al (4), and a combination of the use of a microwave oven (2) and the QIAamp Blood Kit.…”

Section: Methodsmentioning

confidence: 99%

Development of a direct PCR assay for detection of the diphtheria toxin gene

Nakao

Popović

1997

J Clin Microbiol

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PCR has proved to be a reliable tool for the detection of the diphtheria toxin gene, tox, and its use has allowed for the rapid differentiation between toxigenic and nontoxigenic strains. In this study, this PCR was further developed, evaluated, and standardized to detect this gene directly from clinical specimens. Optimal conditions for collection, transport, and storage of the clinical specimens and isolation and purification of DNA from the clinical specimens were defined. With two sets of primers that detect the A and B subunits of the diphtheria toxin gene, sensitivity levels of 50 and 500 CFU/PCR mixture, respectively, were achieved. This PCR was evaluated with 162 clinical samples collected from patients with diphtheria and other upper respiratory tract infections, as well as from healthy individuals.

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Section: Methodsmentioning

confidence: 99%

Development of a direct PCR assay for detection of the diphtheria toxin gene

Nakao

Popović

1997

J Clin Microbiol

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“…For this reason, the diagnosis of Ehrlichia and Anaplasma infection in humans is commonly based on clinical manifestations and serological analyses. Several useful and more sensitive molecular tools, such as polymerase chain reaction (PCR) and nested‐PCR, have been used to detect and identify Ehrlichia and Anaplasma species in both hosts and vectors (Anderson et al., ; Dawson et al., , ; Murphy et al., ; Kocan et al., ; Inokuma et al., ; Kawahara et al., ; de la Fuente et al., ; Torina et al., ).…”

Section: Introductionmentioning

confidence: 99%

Molecular Survey ofAnaplasmaandEhrlichiaof Red Deer and Sika Deer in Gansu, China in 2013

Chen

Liu

et al. 2015

Transbound Emerg Dis

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Anaplasma and Ehrlichia are important emerging tick-borne pathogens in both humans and animals. Here, we conducted a molecular surveillance study in Gansu, China to assess the prevalence of Anaplasma and Ehrlichia spp. in red deer and sika deer based on polymerase chain reaction (PCR) analysis and sequencing of 16S rRNA or msp genes. PCR revealed that the prevalence of Anaplasma ovis, Anaplasma bovis and Anaplasma platys of the Qilian Mountain samples was 32%, 9% and 9%, respectively; the prevalence of Anaplasma ovis, Anaplasma bovis, Anaplasma platys was 20%, 15% and 15% among the Long Mountain samples, respectively. Of the Long Mountain samples, two (5%) of the 40 samples were positive for Ehrlichia canis, but all 44 of the Qilian Mountain samples were negative for E. canis, and no other Anaplasma or Ehrlichia spp. were found in the samples. The phylogenetic tree showed that the newly isolated Anaplasma and Ehrlichia spp. could be classified as belonging to four clades, including an A. bovis cluster, A. ovis cluster, A. platys cluster and E. canis cluster. In addition, Bartonella schoenbuchensis was firstly identified in blood samples from red deer in Gansu, China. Our results provide important data to increase the understanding of the epidemiology of anaplasmosis and ehrlichiosis of red deer and sika deer and will assist with the implementation of measures to control anaplasmosis and ehrlichiosis transmission to red deer, sika deer and other animals in Gansu, China.

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“…E. chaffeensis naturally infects dogs and deer with mild to no clinical signs (Dawson and Ewing, 1992;Davidson et al, 2001;Unver et al, 2002). However, the difficulty, expense, and lack of inbred or gene knockout in these animal models, makes screening in vivo virulence factors prohibitive.…”

Section: Introductionmentioning

confidence: 99%

Discovery of in vivo Virulence Genes of Obligatory Intracellular Bacteria by Random Mutagenesis

Bekebrede

Lin

Teymournejad

et al. 2020

Front. Cell. Infect. Microbiol.

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Ehrlichia spp. are emerging tick-borne obligatory intracellular bacteria that cause febrile and sometimes fatal diseases with abnormal blood cell counts and signs of hepatitis. Ehrlichia HF strain provides an excellent mouse disease model of fatal human ehrlichiosis. We recently obtained and established stable culture of Ehrlichia HF strain in DH82 canine macrophage cell line, and obtained its whole genome sequence and annotation. To identify genes required for in vivo virulence of Ehrlichia, we constructed random insertional HF strain mutants by using Himar1 transposon-based mutagenesis procedure. Of total 158 insertional mutants isolated via antibiotic selection in DH82 cells, 74 insertions were in the coding regions of 55 distinct protein-coding genes, including TRP120 and multicopy genes, such as p28/omp-1, virB2, and virB6. Among 84 insertions mapped within the non-coding regions, seven are located in the putative promoter region since they were within 50 bp upstream of the seven distinct genes. Using limited dilution methods, nine stable clonal mutants that had no apparent defect for multiplication in DH82 cells, were obtained. Mouse virulence of seven mutant clones was similar to that of wild-type HF strain, whereas two mutant clones showed significantly retarded growth in blood, livers, and spleens, and the mice inoculated with them lived longer than mice inoculated with wild-type. The two clones contained mutations in genes encoding a conserved hypothetical protein and a staphylococcal superantigen-like domain protein, respectively, and both genes are conserved among Ehrlichia spp., but lack homology to other bacterial genes. Inflammatory cytokine mRNA levels in the liver of mice infected with the two mutants were significantly diminished than those infected with HF strain wild-type, except IL-1β and IL-12 p40 in one clone. Thus, we identified two Ehrlichia virulence genes responsible for in vivo infection, but not for infection and growth in macrophages.Keywords: Ehrlichia HF strain, Himar1 transposon mutagenesis, mouse virulence, inflammatory cytokines, staphylococcal superantigen-like domain, obligatory intracellular bacteria IMPORTANCE Ehrlichiosis, a sometimes deadly febrile disease in man and animal, is caused by infection with Gram-negative obligatory intracellular bacteria, Ehrlichia. Ehrlichia species lack typical pathogen-associate molecular patterns (PAMPs), such as lipopolysaccharide, peptidoglycan, pili, and flagella, yet they induce acute and/or chronic inflammatory cytokines in infected animals.Bekebrede et al. In vivo Virulence Genes of EhrlichiaStudies to identify virulence factors and PAMPs of Ehrlichia species are hampered by the limitation to applicable genetic tools and small laboratory animal models. Mouse infection with Ehrlichia HF strain provides an excellent model for fatal human ehrlichiosis, as the HF strain is highly virulent in laboratory mice. However, due to inability to culture the HF stain, the use of this model has been limited. As we have succeeded in culturing and who...

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Susceptibility of white-tailed deer (Odocoileus virginianus) to infection with Ehrlichia chaffeensis, the etiologic agent of human ehrlichiosis

Cited by 183 publications

References 7 publications

Development of a direct PCR assay for detection of the diphtheria toxin gene

Development of a direct PCR assay for detection of the diphtheria toxin gene

Molecular Survey ofAnaplasmaandEhrlichiaof Red Deer and Sika Deer in Gansu, China in 2013

Discovery of in vivo Virulence Genes of Obligatory Intracellular Bacteria by Random Mutagenesis

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