title: Quantitative duplex TaqMan real-time polymerase chain reaction for the assessment of the etiologic agent of epizootic bovine abortion.
abstract: Epizootic bovine abortion (EBA), also commonly known as "foothill abortion," is a late-term abortion primarily in beef cattle with significant economic impacts in California, Nevada, and Oregon. The causative agent is a novel deltaproteobacterium (aoEBA) closely related to the order Myxococcales and vectored by the soft-shelled tick Ornithodoros coriaceus. Historically, diagnosis has relied upon the pathologic examination of the fetus and the presence of elevated fetal serum immunoglobulins. Identification of the etiologic agent, a unique deltaproteobacterium, permitted the development of a quantitative duplex real-time polymerase chain reaction (qPCR) using a unique 90-bp sequence of aoEBA 16S ribosomal RNA gene in conjunction with an 88-bp sequence of the bovine β-actin gene. Reaction efficiencies were 100.9% for the 16S aoEBA gene and 93.1% for the bovine β-actin gene. Application of the duplex TaqMan to a set of aoEBA-infected fetal bovine necropsy tissues demonstrated the assay to be robust in quantitatively identifying the aoEBA bacteria and establishing host-tissue pathogen load. Consistent with previously reported immunohistochemical data, organized lymphoid tissue generally carried the heaviest bacterial load as compared to non-lymphoid tissue. The newly developed duplex TaqMan assay will facilitate diagnosis in difficult cases and provide an invaluable tool for delineating the pathogenesis of EBA.
authors.affiliation: University of California-Davis, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, Davis, CA 95616, USA. rsbrooks@ucdavis.edu
authors.forename: Roxann S
authors.initials: RS
authors.lastname: Brooks
authors.forename: Myra T
authors.initials: MT
authors.lastname: Blanchard
authors.forename: Mark L
authors.initials: ML
authors.lastname: Anderson
authors.forename: Mark R
authors.initials: MR
authors.lastname: Hall
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Stott
mesh_terms: D037881:Aborted Fetus / Q000382:microbiology; D000034:Abortion, Veterinary / Q000382:microbiology*; D000818:Animals; D000907:Antibodies, Bacterial; D002417:Cattle; D020564:Deltaproteobacteria / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012336:RNA, Ribosomal, 16S