Experimental transmission of epizootic bovine abortion (foothill abortion)

Stott, Jeffrey L; Blanchard, M; Anderson, Margaret Lavinia; Maas, John; Walker, Richard L.; Kennedy, P. C.; Norman, B. B.; Bondurant, Robert; Oliver, M. N.; Hanks, D.; Hall, Mark R.

doi:10.1016/s0378-1135(02)00109-8

Cited by 22 publications

(31 citation statements)

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“…8 More recently, thymic aliquots from EBA-affected fetuses have been used in a series of experiments to reproduce the disease. 12 Although an infective agent has been presumed to be the cause of EBA on the basis of fetal pathologic changes and results of experimental inoculations, many attempts over the past 40 years have not resulted in isolation of an etiologic agent that has been confirmed to cause EBA. Various agents, including chlamydiae, spirochetes, and viruses, have been incriminated, but none of these agents reliably reproduced EBA.…”

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confidence: 99%

“…1,7 Evidence of bacterial involvement in EBA was supported by the documentation that antibiotic treatment of pregnant heifers could prevent development of EBA in their fetuses. 12 With evidence of antibiotic susceptibility of the EBA agent, molecular techniques were used to identify bacterial DNA in tissues from EBA-affected fetuses. A suppression-hybridization polymerase chain reaction technique was used to identify a 767-base pair fragment of the 16S rDNA gene of a previously undescribed deltaproteobacterium in thymus and other tissues from EBA-affected fetuses.…”

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confidence: 99%

“…9 Various microbiological techniques have been unsuccessful in propagating this bacterium in culture, and as a result, the disease has not been reproduced by pure cultures of this putative causative agent. 12 The study reported here is a retrospective histochemical and immunohistochemical examination of selected tissues from fetuses with naturally acquired and experimentally induced EBA in an effort to identify a possible bacterial agent. Seventy bovine abortion cases were selected from California Animal Health and Food Safety laboratory case material for this retrospective study.…”

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confidence: 99%

“…Thymus was selected for staining because of documented infectivity of this tissue in experimental inoculation of pregnant heifers. 12 An EBA immunohistochemical (EBA IHC) stain was developed to detect the proposed bacteria in formalin-fixed, paraffin-embedded tissue. The EBA IHC stain used sera obtained from field cases of EBA as the primary antibody at a 1:100 dilution in an avidinbiotin-complex procedure, with biotinylated goat antibovine IgG a as the secondary antibody and peroxidase-conjugated streptavidin b as the tertiary reagent.…”

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confidence: 99%

“…Previous research using affected fetal tissue as the inoculum in pregnant cows has reproduced the disease and offered proof that an antibioticsusceptible infective agent was the cause. 12 However, the etiologic agent has not been isolated in culture. There is convincing evidence that a unique and previously undescribed deltaproteobacterium is involved on the basis of consistent demonstration of a specific 16S rDNA partial gene sequence in EBA-affected fetal tissues.…”

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confidence: 99%

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Histochemical and Immunohistochemical Evidence of a Bacterium Associated with Lesions of Epizootic Bovine Abortion

et al. 2006

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Abstract. Epizootic bovine abortion (EBA), a tick-transmitted disease of pregnant cattle grazing foothill pastures, is a major cause of reproductive failure in California and adjacent states. Affected fetuses develop a chronic disease, resulting in late-term abortion or premature calving. Despite investigations spanning 50 years, to the authors' knowledge, the etiologic agent of EBA has not yet been isolated from affected fetuses or the tick vector. The diagnosis of EBA is based on gross and microscopic lesions. Recently, documentation that the etiologic agent is susceptible to antibiotics and identification of a unique 16S deltaproteobacterial rDNA gene sequence in 90% of thymus tissues from aborted fetuses have supported the role of a bacterial infection as the cause of EBA. To determine whether bacteria could be detected in the tissues, histochemical staining and immunohistochemical procedures were used on formalin-fixed, paraffin-embedded tissues. Use of a modified Steiner silver stain revealed small numbers of intracytoplasmic bacterial rods in 37 of 42 thymic samples from EBA-affected fetuses. Improved detection was achieved by use of immunohistochemical staining with serum from EBA-affected fetuses that resulted in detection of numerous bacterial rods in the cytoplasm of histiocytic cells in the thymus from all 42 EBA-affected fetuses. Immunohistochemical examination of additional tissues from 21 field and experimental EBA cases revealed positively stained intracytoplasmic bacterial rods in many organs with inflammatory lesions. Use of the modified Steiner stain and immunohistochemical staining of tissues from negative-control fetuses failed to reveal organisms. To the authors' knowledge, this is the first report to document morphologic evidence of a bacterium associated with the lesions of EBA.

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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