Chlamydia p. associated equine abortion

Chlamydia psittaci is often associated with pet parrots however many types of birds carry the organism including ones that frequent our horse pastures. These include geese, ducks, turkeys, and pigeons. Of particular note is the description in the summary of possible transmission to humans from infected equine fetal tissues and resulting abortion. Taken from Wikipedia:

Chlamydia psittaci is a lethal intracellular bacterial species that may cause endemic avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include feral birds and domesticated poultry, as well as cattle, pigs, sheep, and horses. C. psittaci is transmitted by inhalation, contact, or ingestion among birds and to mammals. Psittacosis in birds and in humans often starts with flu-like symptoms and becomes a life-threatening pneumonia. Many strains remain quiescent in birds until activated by stress. Birds are excellent, highly mobile vectors for the distribution of chlamydia infection, because they feed on, and have access to, the detritus of infected animals of all sorts.

Below we present the problem as seen in Australia but as the organism is wide spread around the world this is likely happening elsewhere:
DrO

A 25-year retrospective study of Chlamydia psittaci in association with equine reproductive loss in Australia
J Med Microbiol. 2020 Dec 1.
Authors
Rumana Akter 1 2 , Fiona M Sansom 2 , Charles M El-Hage 2 , James R Gilkerson 2 , Alistair R Legione 2 , Joanne M Devlin 2
Affiliations

1 Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria 3010, Australia.
2 Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.

Abstract

Introduction. Chlamydia psittaci is primarily a pathogen of birds but can also cause disease in other species. Equine reproductive loss caused by C. psittaci has recently been identified in Australia where cases of human disease were also reported in individuals exposed to foetal membranes from an ill neonatal foal in New South Wales.
Hypothesis/Gap Statement. The prevalence of C. psittaci in association with equine reproductive over time and in different regions of Australia is not known.
Aim. This study was conducted to detect C. psittaci in equine abortion cases in Australia using archived samples spanning 25 years.
Methodology. We tested for C. psittaci in 600 equine abortion cases reported in Australia between 1994 to 2019 using a Chlamydiaceae real-time quantitative PCR assay targeting the 16S rRNA gene followed by high-resolution melt curve analysis. Genotyping and phylogenetic analysis was performed on positive samples.
Results. The overall prevalence of C. psittaci in material from equine abortion cases was 6.5 %. C. psittaci-positive cases were detected in most years that were represented in this study and occurred in Victoria (prevalence of 7.6 %), New South Wales (prevalence of 3.9 %) and South Australia (prevalence of 15.4 %). Genotyping and phylogenetic analysis showed that the C. psittaci detected in the equine abortion cases clustered with the parrot-associated 6BC clade (genotype A/ST24), indicating that infection of horses may be due to spillover from native Australian parrots.
Conclusion. This work suggests that C. psittaci has been a significant agent of equine abortion in Australia for several decades and underscores the importance of taking appropriate protective measures to avoid infection when handling equine aborted material.