Coxiella burnetii infection is associated with placentitis in cases of bovine abortion.

TitleCoxiella burnetii infection is associated with placentitis in cases of bovine abortion.
Publication TypeJournal Article
Year of Publication2000
AuthorsBildfell RJ, Thomson GW, Haines DM, McEwen BJ, Smart N
JournalJournal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
Volume12
Issue5
Pagination419-25
Date Published2000 Sep
ISSN1040-6387
KeywordsAbortion, Veterinary, Animals, Cattle, Cattle Diseases, Coxiella burnetii, Female, Immunohistochemistry, Necrosis, Placenta Diseases, Pregnancy, Q Fever
Abstract

A positive score on a modified acid-fast (MAF)-stained smear test of fresh placenta was used to identify a group of bovine abortion submissions believed to be infected with Coxiella burnetii. Immunohistochemical (IHC) testing for Coxiella and Chlamydia antigens was performed on 14 MAF smear-positive cases as well as 29 MAF smear-negative cases received during the study period. Nine MAF smear-positive cases as well as 1 MAF smear-negative case were Coxiella-positive via the IHC test. No placentas were positive for Chlamydia antigen. Various histopathologic features were categorized for all placentas and the presence or absence of selected risk categories was also graded for each case. The results between Coxiella IHC-positive cases and Coxiella IHC-negative/MAF-negative cases were compared using Fisher's exact test (P value at 95% confidence). Significant associations were found between Coxiella IHC-positive cases and the presence of placental inflammation (P = 0.0027), placental necrosis (P = 0.012), fetal pneumonia (P = 0.0152), and the visibility of Coxiella-like organisms within trophoblasts on hematoxylin and eosin-stained sections (P < 0.0001). Histopathologic features of Coxiella IHC-positive placentas included infiltration of the chorionic stroma by mononuclear cells, necrosis of chorionic trophoblasts, and focal exudation of fibrin and neutrophils. The results indicate that MAF smears are a good screening tool for the presence of Coxiella in placentas from bovine abortion cases and that the detection of this pathogen in aborted placentas via traditional staining or IHC methods is usually associated with placentitis.

Alternate JournalJ. Vet. Diagn. Invest.