Farmers have long been aware of the many diseases than can be transmitted from animals to humans. Some, such as the Hendra Virus, often have fatal consequences.
But changes in human and animal interactions are presenting some new and very real dangers for both species.
In an effort to better understand and minimise the dangers, Australian scientists and veterinarians have embarked upon new research to identify the pathogens involved in a fresh wave of what are termed, emerging infectious diseases, or EIDs.
Recent examples of EIDs globally include Ebola, severe acute respiratory syndrome (SARS) and pandemic influenza, all of which have caused huge economic losses and socioeconomic disruption.
Over 70 per cent of EIDs originate in wildlife but, importantly, they often amplify or adapt in domestic animal populations before spilling over to humans.
Now, scientists say finding such pathogens is vital in combating them and preventing infection.
Dr Ed Annand is an equine veterinarian and epidemiologist who grew up on a cattle property near Yelarbon in southern Queensland.
He’s worked across the equine industry in Queensland, NSW, Victoria and in the UK and has also taught equine reproduction and practice at universities in Queensland and NSW.
He was the first to discover Australian Bat Lyssavirus (ABLV) in horses after attending the first two cases of the disease in 2013. Initially considered potential cases of Hendra Virus, testing initiated by Dr Annand confirmed it was the rabies-like virus, ABLV.
Prior to this finding it was believed ABLV could only be transmitted to humans via bats.
Dr Annand said that discovery highlighted just how much we don’t know about EIDs.
“We are in a period where advances in testing are enabling the discovery of many more diseases that can be transmitted from animals to humans,” he said.
“Think right back to the earliest known diseases - things like rabies, influenza, the plague and cholera - these killed more people than wars and eventually it was discovered they had all come from animals.”
Dr Annand said that while vigilance created by concerns over Hendra had helped, many horses tested negative for Hendra but still fell ill and died.
“It is not uncommon for vets to see horses with severe illness and Hendra-like symptoms, but the tests return negative. Despite many cases being fatal the cause is often not known.” he said.
It is these ‘Hendra negative’ cases that form a crucial part of Dr Annand’s research project.
The work on emerging infectious zoonotic diseases associated with horses is funded by the Dalara Foundation and is a collaboration between the University of Sydney, School of Veterinary Science, Marie Bashir Institute for Infectious Diseases and Biosecurity, the University of Melbourne and the CSIRO Australian Animal Health Laboratory (AAHL).
The project aims to:
- Identify pathogens in horse cases where the Hendra Virus was confirmed negative
- Confirm and characterise unknown pathogens
- Develop additional diagnostic testing tools for the diagnosis of equine respiratory and neurological diseases and see them incorporated into state diagnostic laboratories.
Dr Annand said early detection of these pathogens would not only improve the management of horses showing Hendra virus-like symptoms but also identify pathogens that could potentially transmit to livestock and humans.
He said that would improve Australia’s preparedness to combat outbreaks of emerging infectious diseases.
“We hope this project will assist Australian laboratories to detect a range of pathogens and respond more effectively to new and emerging pathogens,” he said.
“This work will also provide improved understanding to horse owners and industries, help reduce economic losses associated with horse mortalities possibly even infectious reproductive losses, help to better manage and treat these illnesses and facilitate future identification of novel viruses causing similar diseases in humans and other animals.”