An unvaccinated mare residing near Scone in the Upper Hunter Valley, New South Wales (NSW), Australia, has been confirmed positive for Hendra virus, the NSW Department of Primary Industries (DPI) reported June 12. This is the farthest south a case of Hendra in a horse has been diagnosed.
The horse developed neurologic signs on June 7, three days after being confined to a yard. The owners elected euthanasia after the mare became unresponsive to treatment. As the horse was unvaccinated and had sudden-onset neurological signs, the owners contacted the animal diseases hotline.
A district veterinarian from Hunter Local Lands Services visited the property on June 9 to collect samples for Hendra virus testing. Testing at the state veterinary laboratory at Menangle confirmed Hendra infection on June 12.
No other horses on the property are showing any signs of ill health. Their health status will be monitored daily. Officers from NSW health are undertaking risk assessments of people who have had varying degrees of contact with the affected horse to determine their risk.
Tracing of horse movements in the previous 16 days will be undertaken and a Biosecurity Direction is in place to control the movement of animals and people on and off the property.
Hendra virus infection is notifiable in NSW under the NSW Biosecurity Act. Most cases in NSW have been on the north coast, with a case at Kempsey in 2013 being the most southern case prior to the current case, the DPI said.
In NSW to date there have been 22 horse deaths as a result of Hendra virus on 20 properties since the first NSW case in 2006. There have been no human deaths from Hendra virus in NSW.
Hendra Virus 101
Hendra virus was first identified in Australia in 1994. Since then, more than 100 horses in Queensland and NSW have died due to the virus. It has not been confirmed outside of those Australian states.
Flying foxes, Australian fruit-eating bats endemic to tropical and sub-tropical regions, carry the virus. Horses get it by inadvertently ingesting infected droppings or bodily fluids, and humans contract it when handling infected equine patients.
Hendra virus has been known to yield numerous clinical signs in horses including lethargy, respiratory distress, frothy nasal discharge, elevated body temperature (above 40°C, or 104°F), and elevated heart rate; however, authorities caution that infection does not have specific signs.
The zoonotic disease is transmissible to humans and has killed four people since it was first discovered, including an equine veterinarian who contracted the virus after treating an affected foal in 2009.
Vaccination is the most effective way to help manage Hendra virus disease.