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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These changes were marked by 50 days after tick exposure of the dams, but fetal lesions specific enough to permit making the diagnosis of the disease did not develop until days after dams were exposed by tick feeding.

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

Furthermore, the PCR failed to amplify DNA extracted from pure cultures of a selection of bacterial pathogens typically encountered in veterinary medicine or even P. Studies on the pathogenesis of epizootic bovine abortion. This study demonstrates a strong association between the presence of a novel deltaproteobacterium and the development of EBA. In the 43 years since the first description in California, epizootic bovine abortion EBA has been considered but not definitively diagnosed as a cause of late-term abortions on Nevada ranches.

Thus, phylogenetic characterization has been limited to analysis of the 16S ribosomal RNA rRNA gene AFwhich placed this bacterium in the order Myxococcales, suborder Sorangiineae, family Polyangiaceae and most closely related to Sorangium cellulosum.

However, upon more detailed examination, all have been excluded as the probable EBA etiologic agent. These foci frequently formed pyogranulomas.

Diagnosis of epizootic bovine abortion in Nevada and identification of the vector.

This approach was used because preliminary cloning experiments using universal bacterial primers yielded sequences identical to those of Pseudomonas sp.

A specific PCR was subsequently developed to detect the presence of this bacterium in DNA extracted from fetal thymuses. The phylogenetic location of the putative EBA etiologic agent was surprising, since none of the closest relatives have been demonstrated to be mammalian pathogens.

In summary, this work demonstrates a close relationship between a novel bacterium and EBA. Three heifers experimentally challenged with thymus tissue and simultaneously treated with antibiotics demonstrated the EBA agent to be prokaryotic The sequential development of the fetal lesions was studied and the lesions compared with those in both naturally occurring and experimentally induced infections of the dams which either aborted or carried to term.


Six of seven lymph nodes both prescapular and mesenteric and six of the seven spleens were also positive.

Congenital spirochetosis in calves: The unique fetal pathology of EBA has classically served as the only definitive basis of diagnosis 9 In the tick studies, ticks were collected from locations where EBA was considered to be endemic, including the eastern slope of the Sierra Nevada mountain range in California and southeast Oregon, using dry ice as an attractant 614 Experimental and epizootiologic evidence associating Ornithodoros coriaceus Koch Acari: The novel bacterium described in this paper represents only the second member of the delta subdivision of the class Proteobacteria to be a mammalian pathogen the first was Lawsonia intracellularis [ 413 ], the causative agent of porcine proliferative enteropathy.

Non-EBA diagnoses included bovine viral diarrhea, neosporosis, Haemophilus somnusand unknown etiologies.

Modified Gram staining, combined with transmission electron microscopy, provide strong evidence that the bacterium is gram negative. Heifer exposure n Diagnosis a No. Phylogenetic analysis revealed that this pathogen was a deltaproteobacterium closely related to members of the order Myxococcales.

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

In the absence of a cultivable agent, it is proposed that these molecular data are sufficient evidence to classify this bacterium as the etiologic agent of EBA. In light of these data, this bivine was chosen as a primary candidate for the putative agent of EBA.

In these experiments, an additional 13 clones were sequenced. Immunofluorescent examination demonstrated that immunoglobulins Ig G and IgM were present in the vascular lesions. A quantitative serologic assay for diagnosing congenital infections of cattle.

The microbe, which has yet to be successfully cultured in vitro, has proven difficult to purify from necropsy tissues. Argasidae with the exposure of cattle to epizootic bovine abortion in California. Although the unusual clinical presentation and unique fetal pathology associated with EBA have been recognized since the s, the identity of the etiologic agent is unknown.

In contrast, the three challenge control fetuses whose dams did not receive antibiotics all presented with classic EBA-associated lesions, and their tissues were PCR positive.

Detection and identification of previously unrecognized microbial pathogens. The majority of guidelines that have been suggested for sequence-based determination and incriminating of a presumptive microorganism in disease 5 have been satisfied. From the first experiment, sequences corresponding to a novel betaproteobacterium and Ochrobactrum anthropi were identified. Amplicons identified on 1. Consensus phylogram of 2, neighbor-joining trees generated for a 1,bp fragment of the 16S rRNA gene of the putative agent causing EBA compared with sequences from 39 representative genera 7 of the class Deltaproteobacteria.


Flow cytometric analysis identified the presence of P. 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.

The bacterium was also detected in the argasid tick Ornithodoros coriaceuswhich is the recognized vector of EBA. These preliminary results suggest that the abogtion is preferentially associated with lymphoid tissues.

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Polymerase chain reaction for detection of Borrelia coriaceaeputative agent of epizootic bovine abortion. Furthermore, since this technique utilizes gene-specific primers directed toward the commonly sequenced 16S rRNA gene, phylogenetic comparisons with other bacteria were possible. Identification of this vector was facilitated by the demonstration that the geographic distribution of the tick largely parallels epizlotic of EBA 14 The heifers were exposed to the agent of EBA by i natural exposure fetuses were submitted by epkzooticii tick feeding under experimental conditions, or iii inoculation with tissue homogenate bovinr from fetuses previously diagnosed as being EBA positive.

Fetuses from experimentally exposed heifers were obtained either by surgical removal following dam euthanasia captive bolt in the third trimester to days postchallenge or as dead, weak, or healthy calves following natural parturition.

Acute vasculitis developed at the same time as the acute focal-necrotizing lesions. Histologic examination of fetal tissues, particularly the lymphoid organs, is required to confirm a epizoootic 9 A diagnosis of EBA was established on the basis of histopathology and elevated serum immunoglobulin G, as previously defined 910 This study establishes the presence of EBA as a cause of late-term abortion in Nevada.

Similar approaches have been successfully used to boovine microbial pathogens, including those responsible for cat scratch fever, Whipple’s disease, human ehrlichiosis, hepatitis C, and hantavirus pulmonary syndrome 5 Author information Article notes Copyright and License information Disclaimer.

Novel bacterium in phylum Bacteroidetes. Epizootic bovine abortion characterized by foetal hepatopathy.