Work

An epizootic of Chlamydia psittaci equine reproductive loss associated with suspected spillover from native Australian parrots

Year: 2018

Type: article

Abstract: Chlamydia psittaci is an avian pathogen capable of spill-over infections to humans.A parrot C. psittaci strain was recently detected in an equine reproductive loss case associated with a subsequent cluster of human C. psittaci infections.In this study, we screened for C. psittaci in cases of equine reproductive loss reported in regional New South Wales, Australia during the 2016 foaling season.C. psittaci specific-PCR screening of foetal and placental tissue samples from cases of equine abortion (n = 161) and foals with compromised health status (n = 38) revealed C. psittaci positivity of 21.1% and 23.7%, respectively.There was a statistically significant geographical clustering of cases ~170 km inland from the mid-coast of NSW (P < 0.001).Genomic analysis and molecular typing of C. psittaci positive samples from this study and the previous Australian equine index case revealed that the equine strains from different studs in regional NSW were clonal, while the phylogenetic analysis revealed that the C. psittaci strains from both Australian equine disease clusters belong to the parrot-associated 6BC clade, again indicative of spill-over of C. psittaci infections from native Australian parrots.The results of this work suggest that C. psittaci may be a more significant agent of equine reproductive loss than thought.A range of studies are now required to evaluate (a) the exact role that C. psittaci plays in equine reproductive loss; (b) the range of potential avian reservoirs and factors influencing infection spill-over; and (c) the risk that these equine infections pose to human health.is primarily linked to its established role as a globally distributed zoonotic pathogen [1][2][3][4] .Inhalation is considered the main mode of pathogen entry with disease severity ranging from a subclinical infection, mild respiratory disease to life-threatening pneumonia and systemic psittacosis.While there have been rare reports of human-tohuman transmission of C. psittaci 5, 6 , contact with infected birds 7 or substrates contaminated with bird excreta 3, 8, 9 appears to be the major route of exposure and potential transmission.Despite its obligate requirement for a host during the replicative phase of its lifecycle, C. psittaci elementary bodies are known to persist in soil and water following shedding from infected birds 10 .

Source: Emerging Microbes & Infections

DOI: 10.1038/s41426-018-0089-y