Coxiella burnetii infection in association with equine abortion

The University of Melbourne

  • Project code: PRJ-011758

  • Project stage: Closed

  • Project start date: Friday, May 17, 2019

  • Project completion date: Thursday, December 31, 2020

  • National Priority: HOR-Thoroughbred breeding


This project will investigate Coxiella burnetii in samples collected from cases of equine abortion. C. burnetii causes ‘Q fever’ in humans and can also cause abortions in some other species. We have recently detected C. burnetii in 16 cases of equine abortion by PCR screening of samples stored in our laboratory archives (screening of approximately 500 abortion cases, collected mainly from VIC and NSW). In comparison, we detected equine herpesvirus 1 (considered to be a common cause of infectious equine abortion) in 13 cases, and Chlamydia psittaci in 25 cases. To our knowledge, detection of C. burnetii DNA in equine abortion cases has not previously been reported in Australia.
This project aims to use molecular techniques to genetically characterise the C. burnetii present in these 16 historical cases of equine abortion, as well as quantitate the amount of C. burnetii present in the samples. This project also aims to test contemporary samples from equine abortion cases that are either seen by equine veterinarians working at the Melbourne Veterinary School, or in samples that are submitted to our diagnostic laboratories. We will use the results to better understand the biology of C. burnetii in equine abortion, including the potential risks to human and horse health, and possible transmission pathways. The findings from this study can be used to help inform the development of appropriate control measures, this may include appropriate biosecurity and infection control measures, and could include vaccination of staff exposed to high risk material.


Thoroughbred Horses

Research Organisation

The University of Melbourne

Objective Summary

The overarching objective of this project is to understand the significance of C. burnetii for equine health (specifically its association with equine abortion) and any related risk to human health in Australia.
Our specific objectives are to
1) Genetically characterise the C. burnetii detected in 16 historical cases of equine abortion from NSW and VIC and phylogenetically compare the genotypes detected with those from cases of human disease, and those originating from other species.
2) Quantitate the load of C. burnetii present in the 16 historical cases of equine abortion in order to assess the likely level of environmental contamination, and the risk of infection to other horses or staff, after an abortion event.
3) Screen contemporary equine abortion samples for C. burnetii (along with equine herpesvirus 1 and Chlamydia psittaci) and compare the genotypes of any recent C. burnetii samples to those detected in earlier cases
The outcome from this work will be an understanding of the importance of C. burnetti in equine abortion in Australia, and the level of risk that C. burnetii present in aborted material may pose to other horses and to humans. This knowledge can be used to help inform management decisions and implement appropriate control measures.