January 19, 2010

Australia – Cutting Risks Of Hendra Infection

Few of us have experience of being infected with Hendra virus. Given that 4 of the 7 people who have caught Hendra virus have died we'd probably like to keep it that way.

That shouldn't be too hard.

"We know that around 50% of flying foxes have had Hendra virus at some time, yet it does not appear to cause them any problems. All indications are that, on rare occasions, Hendra virus spills over from bats to horses and then from horses to humans "“ there are no known cases of people contracting Hendra virus from flying-foxes" says Dr Stephen Prowse, CEO with the Australian Biosecurity CRC.

Scientists are starting to think that the recent appearance of Hendra virus is a symptom of bats showing stress as a result of changes we've made to the environment. Despite recent annual outbreaks, Hendra infection is rare in horses and people. Hendra virus does not appear to be highly infectious and does not spread easily; however when it does the consequences can be devastating.

Given the role of bats and horses in our current understanding of the disease, clearly the people who need to take the most precautions are wildlife carers, horse owners and vets. Horse owners need to try to minimize the likelihood of contact between fruit bats and horses. And horse owners and veterinarians need to improve their biosecurity and infection control practices.

Prof Rick Speare, Director of the Anton Breinl Centre for Public Health and Tropical Medicine at James Cook University, has recommended improvements in infection control amongst veterinarians and animal handlers.

"It is important that equine vets take the lead in implementing infection control in their day to day activities" says Prof Speare. "Although Hendra virus infection is rare, the effects if someone gets infected are catastrophic. We have to make equine practice safe so spillovers don't occur again."

Prof Speare is now working with the Australian Veterinary Association (AVA), Biosecurity Queensland, Equine Veterinarians Australia and Queensland Workplace Health and Safety to assist veterinarians develop feasible infection control strategies.

The AVA is currently developing improved biosecurity guidelines and departments of Agriculture / Primary Industries are holding workshops on personal and farm biosecurity.

More research is required to get a better understanding of how the virus persists in bats and spreads to horses, and for the development of vaccines, treatments and rapid tests so that in the medium term a multifaceted approach to biosecurity will be possible.

The public should not be unduly concerned about fruit bats, but treat them as they would any other wild animal and enjoy having them in our urban environment.

We need to better learn to live with bats. In this way we can better manage and reduce the risks of Hendra virus outbreaks and allow bats, horses and people to safely share our environment.

Australia, being an island with strong quarantine services, has always had a very good animal health status. In recent years new infectious diseases have emerged in many countries. Most are zoonoses, i.e. spread from animals to humans. Australia has not been spared; Hendra virus and Australian bat lyssavirus have emerged, while longer known diseases like equine influenza have also entered the country. This means that veterinarians and animal handlers must be more cautious in their handling of animals.


Image Caption: This artificially colored electron micrograph of Hendra virus is from the first identified case in Brisbane in 1994. Courtesy CSIRO


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