Chlamydia psittaci is a bacterium carried by birds. It can cause a respiratory disease in people called Psittacosis and has also been linked to abortion in mares.
Since the 2015 Stud Season, Scone Equine Hospital, the DPI, NSW Health and ESC have been conducting an investigation into the possible role of Chlamydia psittaci in equine abortion/stillbirth/neonatal illness. Last year there was a small cluster of cases of Psittacosis in veterinary students who were involved in treating a sick neonatal foal at a university veterinary school. This resulted in the DPI testing samples from equine abortions for Chlamydia psittaci. The bacteria were detected in a small number of equine abortions in NSW last year and have again been detected in equine abortions this year, including some cases in the Hunter. Because the bacteria have not been tested for prior to last year, it is unclear at this time whether Chlamydia is the cause of these abortions or is simply an incidental finding.