Characterization of Pajaroellobacter abortibovis, the etiologic agent of epizootic bovine abortion. Brooks RS(1), Blanchard MT(1), Clothier. J Vet Diagn Invest. May;14(3) Diagnosis of epizootic bovine abortion in Nevada and identification of the vector. Hall MR(1), Hanks D, Kvasnicka W. Kennedy PC, Casaro AP, Kimsey PB, Bon Durant RH, Bushnell RB, Mitchell GM. The development of the fetal lesions of epizootic bovine abortion (EBA) was.

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Springer-Verlag, New York, N. Open in bbovine separate window. Since nucleic acid samples extracted from ticks can often exhibit activity inhibitory to PCR, it was vital to establish an internal amplification control to discriminate true- and false-negative PCR results.

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The development of the fetal lesions of epizootic bovine abortion EBA was studied in a series of experiments and field cases of the disease. Thirty-six experimentally infected fetuses were recovered at periods of 29 to days after their dams had been infected by allowing the vector tick Ornithodorus coriaceus to feed on them. Taxonomic outline of the prokaryotic genera, p.

The phylogenetic location of the putative EBA etiologic agent was surprising, fpizootic none of the closest relatives have been demonstrated to be mammalian pathogens.

In this study, suppression-hybridization PCR was used to identify a fragment of the 16S rRNA gene of a previously undescribed bacterium in thymus tissue derived from affected fetuses. Widespread inflammatory lesions with a vascular orientation are evident in most tissues. Efforts are under way to define additional gene sequences of this unique pathogen, to visualize the agent in affected tissues, and to visually link the rRNA sequence to the bacterium using in situ hybridization techniques on diseased fetal necropsy tissue.


In addition to identifying this novel agent in diseased fetal bovine aborion, PCR has also demonstrated the presence of the deltaproteobacterium in the tick vector, O. Nucleotide sequence accession numbers.

A combination of direct sequencing bp from 25 EBA-positive fetuses representing 16 field cases, four experimental tick transmissions, and five experimental tissue transmissions, the last using thymus homogenate derived from an EBA-positive fetus and Southern blotting of these amplicons was used e;izootic confirm PCR specificity.

Epizootic bovine abortion characterized by foetal hepatopathy. EBA is transmitted to susceptible heifers by the bite of the soft argasid tick, Ornithodoros coriaceus referred to as the pajaroello tick 14 Affected fetuses also have markedly elevated immunoglobulin levels, suggestive of a vigorous fetal immune response.

Characterization of Pajaroellobacter abortibovis, the etiologic agent of epizootic bovine abortion.

EBA-associated lesions are chronic, developing progressively over a period of 3 months or more. Three of these heifers were simultaneously treated with penicillin for 1 week and tetracycline for 3 weeks, while the remaining three were left untreated to serve as challenge controls These foci frequently formed pyogranulomas.

Epizootic bovine abortion Abortionnfirst identified in the s, is a major contributor of economic loss to epizootlc U. These primer regions showed the most variation compared with other bacterial sequences in multiple-nucleotide alignments. Thymic lesions unique to EBA include a loss of cortical thymocytes and extensive infiltration of macrophages into the medulla. Vaccination of cattle against epizootic bovine abortion.


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The tick was identified on ranches and in geographic areas northern and northwestern counties of Nevada coincident with diagnosis of multiple epiootic of EBA. Denaturing gradient gel electrophoresis: These data imply a close association between this novel agent and the etiology of EBA.

Gross lesions include mucosal and thymic hemorrhages, lymphadenopathy, splenomegaly, hepatomegaly, and ascites. Characterization of Borrelia coriaceae antigens with monoclonal antibodies. Sequence-based identification of microbial pathogens: Thymuses from all seven fetuses were PCR positive.

Epizootic bovine abortion: histogenesis of the fetal lesions.

These three heifers gave birth to healthy calves; two were euthanized immediately prior to consumption of colostrum for PCR analysis; all tissues were PCR negative. Studies on the pathogenesis of epixootic bovine abortion. Inoculation with negative control necropsy tissue. Experimentally induced immunity to chlamydial abortion of cattle.

The tick lives in tree and brush litter in deer and cattle beds, feeds rapidly in less than an hour under experimental conditionsand then departs the host.