Another six people have been tested for the deadly Hendra virus after it claimed the life of a seventh horse, officials said Thursday, as the killer outbreak spread south.
At least 32 people have now been exposed to Hendra, a rare virus spread from horses which can cause fatal respiratory illness in humans, after a second case was confirmed in populous New South Wales state.
"In NSW we now have single horse deaths to Hendra virus on two properties ... and 15 people who have been in contact with the affected horses," said the state's chief veterinarian, Ian Roth.
The latest outbreak, at Macksville, about 500 kilometres (310 miles) from Sydney, is the furthest south it has ever been detected, and only the third time Hendra has been seen in NSW.
One horse died and another three were being monitored, Roth said, adding that it was not believed to be linked to any of the other cases.
There have been three other outbreaks in neighbouring Queensland state since June, exposing 17 people to sick animals.
A total of 32 people are now being tested for the virus, which has killed four of the seven people who contracted it in 18 outbreaks since it was first documented in 1994.
Named after the Brisbane suburb in which is was first detected and thought to be unique to Australia, Hendra is believed to be carried by fruit bats (flying foxes) and spread via their urine and droppings.
The bats, which have no symptoms of disease, then pass the infection to horses, possibly via half-chewed fruit or other water or food they contaminate, and these animals then transmit it to humans.
Health officials stressed that high levels of exposure were required for a human to contract Hendra from a horse and there had been no evidence of bat-to-human or human-to-human infection.
Explore further: Research helps steer mites from bees