title: A prospective study of sheep and goat abortion using real-time polymerase chain reaction and cut point estimation shows Coxiella burnetii and Chlamydophila abortus infection concurrently with other major pathogens.
abstract: From 2009 to 2011, 163 sheep and 96 goat abortion submissions were received at the Animal Health Laboratory, University of Guelph, Ontario, Canada, for gross and histologic examination, as well as real-time polymerase chain reaction (PCR) testing for Chlamydophila abortus and/or Coxiella burnetii. Additional testing included immunohistochemistry for Toxoplasma gondii and Chlamydophila spp., routine bacterial culture and selective culture for Campylobacter spp., examination of modified acid-fast-stained placenta smears, enzyme-linked immunosorbent assay testing for Chlamydophila spp., and virus isolation. The final diagnosis made for each case by individual pathologists, based on gross and histologic lesions, as well as ancillary testing, was used as a standard to determine the significance of C. abortus and C. burnetii infection. Coxiella burnetii was identified by real-time PCR in 113 of 163 (69.0%) and 72 of 96 (75%) sheep and goat abortion submissions, respectively, but was considered to be significant in causing abortion in only 11 of 113 (10%) sheep and 15 out of 72 (21%) goat submissions that tested positive. Chlamydophila abortus was identified by real-time PCR in 42 of 162 (26%) and 54 of 92 (59%) sheep and goat submissions, respectively, but was considered the cause of the abortion in 16 of 42 (38%) sheep and 34 of 54 (63%) goat submissions that tested positive. Optimal sensitivity and specificity cut points for the real-time PCR copy number for C. abortus and C. burnetii were determined using the final pathology diagnosis as the reference test.
authors.affiliation: Animal Health Laboratory, University of Guelph, Guelph, ON, Canada. mhazlett@uoguelph.ca
authors.forename: Murray J
authors.initials: MJ
authors.lastname: Hazlett
authors.forename: Rebeccah
authors.initials: R
authors.lastname: McDowall
authors.forename: Josepha
authors.initials: J
authors.lastname: DeLay
authors.forename: Margaret
authors.initials: M
authors.lastname: Stalker
authors.forename: Beverly
authors.initials: B
authors.lastname: McEwen
authors.forename: Tony
authors.initials: T
authors.lastname: van Dreumel
authors.forename: Maria
authors.initials: M
authors.lastname: Spinato
authors.forename: Brian
authors.initials: B
authors.lastname: Binnington
authors.forename: Durda
authors.initials: D
authors.lastname: Slavic
authors.forename: Susy
authors.initials: S
authors.lastname: Carman
authors.forename: Hugh Y
authors.initials: HY
authors.lastname: Cai
mesh_terms: D000034:Abortion, Veterinary / Q000382:microbiology*; D000818:Animals; D001431:Bacteriological Techniques; D023501:Chlamydophila / Q000145:classification; D023521:Chlamydophila Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D060085:Coinfection / Q000662:veterinary; D016997:Coxiella burnetii / Q000302:isolation & purification*; D005260:Female; D015511:Goat Diseases / Q000382:microbiology* / Q000473:pathology; D006041:Goats; D011247:Pregnancy; D011778:Q Fever / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology* / Q000473:pathology; D014124:Toxoplasmosis, Animal / Q000175:diagnosis
keywords: Abortion; Chlamydophila abortus; Coxiella burnetii; goats; real-time polymerase chain reaction.; sheep