Caring for koalas

Volume 6 Number 2 February 8 - March 8 2010

Third year Veterinary Science student Jessica Goh and Senior Veterinarian at the Australian Wildlife Health Centre at the Healesville Sanctuary Dr Rupert Baker, a Melbourne Honours graduate in Veterinary Science with “Prickles” a three-year-old koala born in the wild and orphaned when her mother was killed by a car
Third year Veterinary Science student Jessica Goh and Senior Veterinarian at the Australian Wildlife Health Centre at the Healesville Sanctuary Dr Rupert Baker, a Melbourne Honours graduate in Veterinary Science with “Prickles” a three-year-old koala born in the wild and orphaned when her mother was killed by a car

Three Melbourne Veterinary students are working with the Australian Wildlife Health Centre at the Healesville Sanctuary to help orphaned koalas survive. Shane Cahill reports.

It all looks too easy.

The koala sitting far up the gum tree has a home and food supply combined into one renewable package.

But as a group of Melbourne Veterinary Science students have discovered, the process of transforming the raw material of eucalyptus leaves is a highly complex process, which, in the case of orphaned and injured koalas becomes a matter of life or death.

“Koalas are not born with the gut flora they need to produce the microorganisms that break down the cellulose from their diet of eucalyptus leaves allowing the koalas to absorb the fatty acids the microbes produce,” explains project leader, Vivien Tam.

“Juvenile koalas need to have their gut flora established by their parents during weaning by a behaviour known as papping or pap feeding.”

Pap is special maternal faeces produced by the parent koala. It is made in the caecum and then passed in the faeces. It is consumed by the juvenile several times a week when they first emerge from the pouch at about the age of six months.

All as nature intended. But what happens when an orphaned koala that has not yet consumed pap comes into care?

“Without a substitute for pap dysbiosis is likely to result and the animal would suffer disrupted normal gut function and weight loss in extreme cases requiring euthanasia,” says team member Sue-Mae Chua.

As a stop gap measure samples of koala caecal contents are stored refrigerated at Healesville Sanctuary. This can then be used to feed animnals that require pap.

“Unfortunately it can only be stored for two weeks and bacterial death reduces the efficacy of the sample,” says Jessica Goh, who completes the team.

The students received a 2009 Knowledge Transfer Student Grant allowing them to work with Dr Rupert Baker, senior veterinarian at the Australian Wildlife Health Centre at the Healesville Sanctuary to develop a possible solution to the problem.

“Having a pap substitute can also be critical in the treatment of injured koalas,” Dr Baker says.

“Sometime antibiotics are necessary to treat injuries and this can destroy the caecal bacteria making the animal unable to digest its food.  It would be great to have pap in a form it can be stored and used when needed.“

“We will be taking tannin protein complex degrading enterobacteria and freeze drying them,” Ms Tam says.

“Freeze drying is a standard process for storing bacteria in laboratories for long periods and we are hopeful it will assist orphaned koalas in care and also injured koalas who have their normal gut flora wiped out after the administration of a broad range of antibiotics.”

The team will determine if on reconstitution freeze drying, storage and thawing will result in viable organisms.

“We would be using serial dilutions of pre-thawed and post-thawed samples and culture them on a selective medium to determine the viability of the organism by surface plate counts,” Ms Tam says.

The team believes the project provides a real world application to what they have learned in their microbiology lectures. It has the potential to have widespread application for koalas receiving care across Australia.