Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.
NSW Department of Primary Industries, Animal and Plant Health laboratories, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia.
Aust Vet J. 2022 Dec;100(12):600-604. doi: 10.1111/avj.13206. Epub 2022 Sep 7.
Chlamydia psittaci is a recognised cause of late-term equine foetal loss and poses a zoonotic risk in Australia. However, a management strategy is lacking to protect at-risk humans handling infected aborted material and pregnant mares. This study proposes a protocol for approaching C. psittaci foetal loss after investigating four foetal losses that occurred on a horse stud in the Hunter Valley, Australia in 2021. Swabs from the foetal loss cases (n = 4), close contact mares (n = 59), and foals of the close contact mares (n = 33) were collected and tested for C. psittaci using both isothermal points of care and quantitative polymerase chain reaction (qPCR) laboratory-based testing. Genotyping was performed utilising C. psittaci multilocus sequence typing and ompA sequencing from C. psittaci positive pooled foetal and placental (n = 3) DNA. Foetal and placental samples from the four foetal loss cases were all positive for C. psittaci with 100% agreement between the isothermal swab testing on the farm and qPCR DNA testing at an external laboratory. Genotyping revealed the clonal and identical sequence type 24 (ST24) C. psittaci strains in all samples. C. psittaci was not detected in close contact with mares or their foals. There was no statistically significant difference in foal survival between the close contact mare groups that did and did not receive antimicrobial intervention (P > 0.05). The proposed protocol is intended to raise awareness and begin a discussion for guidelines around handling of chlamydial foetal loss cases in late pregnant mares which pose a zoonotic threat to farm workers and veterinarians.
鹦鹉热衣原体是公认的马驹晚期流产原因，并在澳大利亚构成动物传染病风险。然而，目前缺乏保护接触感染流产材料和妊娠母马的高危人群的管理策略。本研究通过调查 2021 年在澳大利亚亨特谷的一个马场发生的四例胎儿流产病例，提出了处理鹦鹉热衣原体胎儿流产的方案。从流产病例（n=4）、密切接触母马（n=59）和密切接触母马的驹（n=33）中采集拭子，使用等温点护理和定量聚合酶链反应（qPCR）实验室检测方法检测鹦鹉热衣原体。利用鹦鹉热衣原体多位点序列分型和 ompA 测序对来自阳性 pooled 胎儿和胎盘的鹦鹉热衣原体（n=3）DNA 进行基因分型。四例流产病例的胎儿和胎盘样本均为鹦鹉热衣原体阳性，农场等温拭子检测与外部实验室 qPCR DNA 检测的一致性为 100%。基因分型显示所有样本均为克隆和相同的 24 型（ST24）鹦鹉热衣原体株。在密切接触的母马及其驹中未检测到鹦鹉热衣原体。接受和未接受抗菌干预的密切接触母马组的驹存活率无统计学差异（P>0.05）。拟议的方案旨在提高认识，并开始讨论处理妊娠晚期母马中存在动物传染病风险的衣原体胎儿流产病例的准则，这些病例对农场工人和兽医构成动物传染病威胁。
