Equine abortion due to Chlamydia psittaci in South Australia with zoonotic transmission

Chlamydia psittaci was detected by real-time PCR in the lung, liver and kidney of an equine foetus that had aborted in South Australia in August 2023. The corresponding microscopic lesions included lymphocytic and histiocytic chorionitis, necrosis of placental villi associated with bacteria in the cytoplasm of trophoblastic epithelial cells, and multiple microgranulomas in the liver. Equine chlamydial abortion had not been diagnosed previously in South Australia. Eight days after examining the foetus and placenta, the veterinary pathologist developed fever and subsequently was admitted to hospital. Specimens were obtained from the patient by bronchoscopy, and C. psittaci was detected by real-time PCR in the submitted bronchial washings. This is the first report of zoonotic C. psittaci infection acquired by handling infected equine tissues to be confirmed by real-time PCR.