OJD Detected In Australian Wildlife

August 27, 1999 The Rural News

Adelaide - Evidence of the sheep wasting condition Ovine Johnes Disease has been detected in Australian wildlife for the first time.

Veterinarians Debbie Lehmann and Greg Johnson discovered the bacteria which causes the disease in tissue culture from the small intestine of two tammar wallabies on South Australia's Kangaroo Island.

The husband-and-wife team conducted a study into 10 kangaroos, 34 tammar wallabies and 46 brushtail possums on a property infected by the disease.

Ovine Johnes disease affects the sheep's gut and associated lymph nodes, making it unable to digest food and leading to chronic wasting and death. The disease is also known to occur in cattle.

The bacteria causing the disease is passed on through the animals' faeces, contaminating pastures grazed by other animals.

Dr Lehmann said more studies had to be done to find out whether wallabies were affected by the disease and whether they could transmit it.

"I was concerned that we have more wallabies grazing our pastures on Kangaroo Island than we do sheep and I was also concerned that the infection may be getting into the wildlife," Dr Lehmann said.

"We don't know whether the organism will actually cause disease in our wildlife.

"We have to look further at whether it actually causes an infection to the stage it's going to allow multiplication of the bugs and contamination of the pastures by the wallabies themselves?'

She said it was important to find out if wallabies could transmit the disease and whether that could affect destocking as a means of control. If farmers were going to remove and destroy sheep, they needed to know whether pastures could still be infected before restocking.

"We're assuming that the infection has come from the sheep into the wallaby," Dr Lehmann said.

"We need to do more studies into the role that wallabies have to play in the spread of this disease and the control of this disease."

Ovine Johnes disease was first detected on Kangaroo Island, 120 km south-west of Adelaide, in June last year.

Since then, 23 of the island's 350 farms have been found to be infected with the disease, which poses no threat to humans.