title: Experimental challenge of pregnant cattle with the putative abortifacient Waddlia chondrophila.
abstract: Waddlia chondrophila is a Gram-negative intracellular bacterial organism that is related to classical chlamydial species and has been implicated as a cause of abortion in cattle. Despite an increasing number of observational studies linking W. chondrophila infection to cattle abortion, little direct experimental evidence exists. Given this paucity of direct evidence the current study was carried out to investigate whether experimental challenge of pregnant cattle with W. chondrophila would result in infection and abortion. Nine pregnant Friesian-Holstein heifers received 2 × 108inclusion forming units (IFU) W. chondrophila intravenously on day 105-110 of pregnancy, while four negative-control animals underwent mock challenge. Only one of the challenged animals showed pathogen-associated lesions, with the organism being detected in the diseased placenta. Importantly, the organism was re-isolated and its identity confirmed by whole genome sequencing, confirming Koch's third and fourth postulates. However, while infection of the placenta was observed, the experimental challenge in this study did not confirm the abortifacient potential of the organism.
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wheelhouse
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Allen
authors.initials: A
authors.lastname: Flockhart
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Kevin
authors.initials: K
authors.lastname: Aitchison
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Morag
authors.initials: M
authors.lastname: Livingstone
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Jeanie
authors.initials: J
authors.lastname: Finlayson
authors.affiliation: Biosellal, 317 Avenue Jean Jaurès, 69007 Lyoncedex, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Flachon
authors.affiliation: Biosellal, 317 Avenue Jean Jaurès, 69007 Lyoncedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Sellal
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Dagleish
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Longbottom
mesh_terms: D000031:Abortion, Septic / Q000378:metabolism / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D000818:Animals; D002417:Cattle / Q000378:metabolism / Q000382:microbiology; D002418:Cattle Diseases / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D002695:Chlamydiales / Q000378:metabolism / Q000472:pathogenicity; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000378:metabolism / Q000473:pathology; D010922:Placenta Diseases / Q000378:metabolism / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D011247:Pregnancy