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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Preliminary characterization and pathogenicity studies of a virus isolated from ticks Ornithodoros coriaceus and from tick-exposed cattle.
These lesions were similar to immune-mediated lesions that result from the deposition of toxic complexes in the tissues. Springer-Verlag, New York, N.
Epizootic bovine abortion: histogenesis of the fetal lesions.
Although these agents were abortioh in some of the DNA samples, the pattern for neither bacterium paralleled the clinical and histopathological diagnosis of EBA data not shown. In Bergey’s manual of systematic bacteriology2nd ed.
Instruments were subjected to bleach and heat treatment alcohol burn between collections of individual organs. Thirty-six experimentally infected fetuses were recovered eizootic periods of 29 to days after their dams had been infected by allowing the vector tick Ornithodorus coriaceus to feed on them.
Sequence-based identification of microbial pathogens: The histologic thymic changes were characteristic of EBA and included severe histocytic thymusitis with depletion of thymocytes, interlobular hemorrhage, and fibrinocellular exudation. This approach was used because preliminary cloning experiments using universal bacterial primers yielded sequences identical to those of Pseudomonas sp. The phylogenetic position of SerratiaButtiauxella and some other genera of the family Enterobacteriaceae.
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Epizootic bovine abortion: histogenesis of the fetal lesions.
Acute necrotizing foci developed in several organs, but most commonly in lymph nodes and spleen. Gross lesions include mucosal and thymic hemorrhages, lymphadenopathy, splenomegaly, hepatomegaly, and ascites.
Investigation of these losses has defined a specific fetal syndrome characterized by late-term abortion or birth of weak or dead calves.
Identification and sequencing of the groE operon and flanking genes of Lawsonia intracellularis: Six of seven lymph nodes both prescapular and mesenteric and six of the seven spleens were also positive.
A specific PCR was developed described in Materials and Methods to detect this deltaproteobacterium in bovine tissues. Abortio examination of fetal tissues, particularly the lymphoid organs, is required to confirm a diagnosis 9 Concurrent treatment with antibiotics at the time of EBA challenge abolished infection of the fetus and therefore implicated epizoogic prokaryotic organism as the likely causative agent Flow cytometric analysis identified the presence of P.
In addition, with the development of a diagnostic PCR, efforts can be initiated to better define the ecology of EBA, including the identification of additional reservoirs of the bacterium and defining the association between the EBA agent and the tick vector. Acute vasculitis developed at the same time as the acute focal-necrotizing lesions.
Three heifers experimentally challenged with thymus tissue and simultaneously treated with antibiotics demonstrated the EBA agent to be prokaryotic Affected fetuses also have markedly elevated immunoglobulin levels, suggestive of a vigorous fetal immune response. Experimentally induced immunity to chlamydial abortion of cattle. Thymuses from all seven fetuses were PCR positive. Although all bacterial culture attempts have been unsuccessful, this breakthrough provided sufficient direction to develop a molecular approach for the identification of the etiologic agent.
Diagnosis of epizootic bovine abortion in Nevada and identification of the vector.
Vaccination of cattle against epizootic bovine abortion. Immunofluorescent examination demonstrated that immunoglobulins Ig G and IgM were present in the vascular lesions.
This article has been cited by other articles in PMC. 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.
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.
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 The inability to identify the agent in all ticks would be consistent with the low-level infection achieved by experimental transmission of EBA to cattle by tick bite.
Tissue Presence of agent in fetus a: Fetal necropsy tissues were obtained from a combination of field-infected and experimentally infected heifers, as previously described 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 to confirm PCR specificity.
These preliminary results suggest that the agent is preferentially associated with lymphoid tissues.
Experimental transmission of epizootiv bovine abortion foothill abortion. Taxonomic outline of the prokaryotic genera, p. The recent development of a challenge system in which inoculation of EBA-diseased bbovine thymus into pregnant 90 to days of gestation heifers could result in consistent and predictable transmission of the EBA agent has facilitated efforts to define the causative organism Two different fetal bovine thymic pools containing tissue homogenates from two EBA-positive tester or three EBA-negative driver individual cases were prepared by phenol-chloroform extraction
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