RESUMO
Bovine abortion represents a major animal welfare issue and a cause of substantial economic loss yet the rate of successful diagnosis remains low. Chlamydia-related organisms including Parachlamydia have recently emerged as putative cattle abortifacients. Placental tissue samples and fetal lung from bovine abortion submissions across Scotland in Spring 2011 were investigated by histopathology for the presence of suspect Chlamydia-related organisms. Evidence of Chlamydia-related organisms was observed in 21/113 (18.6%) placenta samples. Thirteen of the suspect cases and 18 histopathology negative cases were analysed by molecular and immunohistochemical methods. All samples were PCR positive for Parachlamydia but sequencing revealed high homology between identified environmental 16S sequences in all but three cases. Parachlamydial antigen was detected in 10/31 placental samples (32.2%) with pathology consistent with chlamydial infection. This work supports the need for further surveillance investigations and experimental studies to determine the role of Parachlamydia in bovine abortion.
Assuntos
Aborto Animal/microbiologia , Antígenos de Bactérias/isolamento & purificação , Doenças dos Bovinos/microbiologia , Chlamydiales/imunologia , Infecções por Bactérias Gram-Negativas/veterinária , Complicações Infecciosas na Gravidez/veterinária , Feto Abortado/microbiologia , Aborto Animal/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Chlamydiales/isolamento & purificação , Feminino , Feto/microbiologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Imuno-Histoquímica/veterinária , Pulmão/microbiologia , Placenta/microbiologia , Reação em Cadeia da Polimerase/veterinária , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/patologia , RNA Ribossômico 16S/análise , Escócia/epidemiologiaRESUMO
A substantial proportion of the causes of infectious bovine abortion remain largely undiagnosed, potentially due to the presence of previously unrecognised infectious agents. Recently, several reports have demonstrated the presence of Parachlamydia sp. in placental and foetal tissues derived from bovine abortions of unknown aetiology but the route of transmission remains undefined. The drinking water from one such recent case study was analysed for the presence of Parachlamydia sp. as a potential source of infection. Chlamydiales sp. 16S rRNA genes were PCR-amplified from the drinking water and a 16S rRNA gene clone library constructed. DNA sequencing of thirty-one clones indicated the presence of organisms belonging to the Parachlamydiaceae, specifically the genera Parachlamydia and Neochlamydia. Seven 16S rRNA gene sequences were identical to a Parachlamydia sp. sequence obtained from placental tissue from an abortion case originating from the same farm. These results raise the possibility that the drinking water is a source of Parachlamydia, which may play a role in infectious bovine abortion.
