Australian Hendra Virus Case Total Continues to Rise

The total number of confirmed hendra virus cases has reached 14, according to Chris Reardon, BVSc(Hons), BSc(Hons), MACVSc, CMAVA, president of Equine Veterinarians Australia. The Australian Veterinary Association indicated that the cases occurred on eight properties in Queensland and three in New South Wales.

Reardon explained that this year's total matches the total number of cases Australia had ever seen prior to this year: "Until this year there were 14 cases over 17 years. In the last six weeks there have been 14 more nationally."

The most recent cases of the zoonotic disease were confirmed in Queensland on July 22. One confirmation came from a horse that died last month in Logan, and the other came from a recent equine fatality in Chinchilla.

With the Chinchilla case, Reardon confirmed the virus is spreading to new areas of the country.

"On July 24 the first (known) case of hendra west of the Great Dividing Range (Australia's largest mountain range located about 250 km, or 155 miles, inland of the island's east coast) was reported."

In early July hendra also was confirmed in a New South Wales horse, which is the furthest south the virus has ever been found.

"There is virus in flying fox colonies in every state of Australia, and it is possible that new cases could appear in other states in the future," Reardon added. "Furthermore, the large movement of horses across this country does mean that the chance for interstate spread exists.

"The number of new cases has increased dramatically this year," Reardon continued. "The reason for this is largely unknown. Suggested reasons include increased viral shedding by the flying foxes, a change to the flying fox/horse interaction, better detection methods used, and perhaps more awareness and increased surveillance."

Confirmed cases of hendra virus have been reported as late as September in the past, Reardon said, so this year's season "is far from over."

Reardon relayed that Australian veterinarians are concerned about the spike in new cases this year and are awaiting the arrival of a hendra vaccine: "We are eagerly awaiting the release of the equine vaccine for hendra virus, which has been successfully developed at Commonwealth Scientific and Industrial Research Organization's Australian Animal Health Laboratory. The vaccine will need to undergo further testing and commercial development before an expected release date in 2013. The Australian Veterinary Association believes all horses should be vaccinated and a microchip implant be used for identification and traceability."

Hendra virus (which has killed at least 40 horses since its discovery) has been known to yield numerous clinical signs in horses including respiratory distress, frothy nasal discharge, elevated body temperature (above 40°C, or 104°F), and elevated heart rate; however, authorities caution that hendra infection does not have specific signs.

The zoonotic disease is transmissible to humans and has killed four people since it was first discovered in 1994, including an equine veterinarian who contracted the virus after treating an affected foal in 2009.

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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