Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses

Abstract

Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.

A 25-year retrospective study of Chlamydia psittaci in association with equine reproductive loss in Australia

“… C. psittaci is known to be present in other species (particularly birds and humans) in all Australian states and territories [32, 38–40], but has only previously been implicated as a cause of equine abortion in NSW and VIC [21, 23]. The C. psittaci -negative samples from QLD, NT, TAS and WA were all collected in years during which C.…”

“…All cases of C. psittaci equine abortion cases in Australia have been the 6BC/ST24 genotype [21, 23, 24, 26]. These results suggest that Australian parrots may be the reservoir of equine C.…”

“…Most recently C. psittaci has also been identified as the suspected cause of equine reproductive loss in three cases in Victoria (VIC), Australia [23]. Sequence analysis of the outer-membrane protein A ( omp A) as well as multi-locus sequence typing (MLST) revealed that the detected C.…”

“…This prompted a number of related studies [ 12, 21, 22 ] that demonstrated C. psittaci in 21 % of cases of equine reproductive loss in New South Wales (NSW), Australia [ 21 ]. Most recently C. psittaci has also been identified as the suspected cause of equine reproductive loss in three cases in Victoria (VIC), Australia [ 23 ]. Sequence analysis of the outer-membrane protein A ( omp A) as well as multi-locus sequence typing (MLST) revealed that the detected C. psittaci clustered with the avian 6BC clade [ 17, 24 ].…”

Real-time fluorometric and end-point colorimetric isothermal assays for detection of equine pathogens C. psittaci and equine herpes virus 1: validation, comparison and application at the point of care

“…Horses are a key part of One Health due to their role in transmission of both viral and bacterial diseases from wildlife to humans [ 1 , 2 ]. C. psittaci ( C. psittaci ) has recently emerged as an equine abortigenic pathogen causing significant losses to the Australian Thoroughbred industry [ 3 – 5 ]. Furthermore, this zoonotic pathogen has attracted attention due to the apparent transmission of C. psittaci from equine placental membranes to humans causing severe respiratory illness [ 6 , 7 ].…”