Detection of Coxiella burnetii and equine herpesvirus 1, but not Leptospira spp. or Toxoplasma gondii, in cases of equine abortion in Australia - a 25 year retrospective study.
Authors: Akter Rumana, Legione Alistair, Sansom Fiona M, El-Hage Charles M, Hartley Carol A, Gilkerson James R, Devlin Joanne M
Journal: PloS one
Summary
# Editorial Summary Over a 25-year period, researchers at the University of Melbourne examined 600 aborted equine foetal tissues using qPCR to establish the prevalence of four major infectious agents implicated in equine abortion: Coxiella burnetii, Leptospira spp., Toxoplasma gondii, and equine herpesvirus 1 (EHV-1). C. burnetii was identified in 4% of cases overall (3% in Victoria, 6% in New South Wales), with clustering of positive cases in 1997–2003 and 2016–2018, whilst EHV-1 was detected at 3% prevalence; notably, neither Leptospira nor Toxoplasma DNA was found in any sample. Given that C. burnetii is a zoonotic pathogen responsible for Q fever in humans and can survive in harsh environmental conditions, these findings warrant serious consideration of biosafety protocols when managing aborted foetal tissues and contaminated materials, particularly for farriers, vets, and stable staff who may have direct exposure. Whilst the data confirm C. burnetii's presence in Australian equine abortion cases, the research underscores the need for targeted epidemiological investigation to clarify whether this organism is a primary aetiological agent or an incidental finding, and highlights the importance of differential diagnosis when investigating abortion clusters on breeding farms.
Read the full abstract on PubMed
Practical Takeaways
- •Implement protective measures (PPE, safe handling protocols) when managing equine abortions due to zoonotic risk of C. burnetii (Q fever) to humans
- •Consider C. burnetii as a potential infectious cause of equine abortion in Australia, particularly in NSW where prevalence is higher
- •While EHV-1 remains a primary cause of infectious abortion, diagnostic testing should include investigation of other pathogens as multiple agents can be involved
Key Findings
- •Coxiella burnetii was detected in 4% of 600 aborted equine foetal tissues, with highest incidence 1997-2003 and 2016-2018
- •Equine herpesvirus 1 DNA was detected in 3% of samples
- •Regional variation in C. burnetii prevalence: 3% in Victoria, 6% in New South Wales
- •Leptospira spp. and Toxoplasma gondii DNA were not detected in any samples tested