Research To Protect Kangaroos (5/17/2007)

Kirsty and her fly-trap - Photo Credit: James Cook University

A PhD student from James Cook University hopes her research will help defend Australian shores from an exotic wasting disease which, in the event of an outbreak, could have devastating implications for the iconic kangaroo.

Kirsty Van Hennekeler has spent four years studying Surra, the disease caused by a parasite of the mammalian blood system which causes fever, weakness, and lethargy and can lead to weight loss, anaemia and even death in an infected animal.

The JCU vet has specifically been looking at the March fly as a potential vector of Trypanosoma evansi, the protozoa which causes Surra.

"Surra is not in Australia at the moment but it is of high quarantine risk and a major threat to our biosecurity socially, economically and environmentally," she said.

The major concern associated with an incursion of Surra is that not only will the production animal industries suffer; but it would have a significant impact on our country's native wildlife.

The disease is transmitted through blood residue left on the mouth of a March fly within six hours of feeding from an infected animal.

"It appears that marsupials, like wallabies and kangaroos, are severely affected by this disease and suffer a high mortality rate," Ms Van Hennekeler said.

Surra is already found in Africa, the Middle East and, more pertinent for Australia, northern Indonesia, East Timor and the Philippines.

"It is more likely that the disease will be bought to Australia by an infected animal rather than wind swept insects," she said.

"If it gets to Papua New Guinea, it is conceivable to think that an infected dog or deer could swim between the islands of the Torres Strait and reach the northern tip of Australia."

The biggest part of Ms Van Hennekeler's project was to monitor March flies at the Cape York Peninsula - the highest risk area for possible incursion - and in Townsville. Over two wet seasons, in collaboration with a team from Murdoch University, she monitored 11 sites to establish the fly's seasonal dynamics.

The group she is most interested in is the Tabanid family and specifically species of Tabanus because they are most likely to be transmitters of the disease.

In 21 months, Ms Van Hennekeler found 38 species at Cape York and eight in Townsville. The three main species collected in Townsville were the Tabanus townsvilli, Tabanus pallipennis and Pseudotabanus silvester.

"I found that the flies were abundant at Lockhart River, the high rainfall making it a really good environment for breeding," she added.

During the project she also compared different trapping methods. She found the flies were most attracted to Carbon Dioxide and Octenol.

"It makes sense that the flies were attracted to these two," she said. "CO2 is a by-product of respiration and Octenol is basically essence of cow breath. Putting them both together had an even better effect."

With funding from Australian Biosecurity CRC, Ms Van Hennekeler is now producing a risk model for Trypanosoma evansi.

"The risk model will help predict when and where the risk of incursion is the highest so we can better focus our surveillance efforts," she said.

"The next step is to produce a Geographical Information System (GIS) map combining all the information we have. That is the really exciting bit because in theory someone should be able to look at the map and easily identify where the highest risk if incursion is."

Ms Van Hennekeler hopes to complete the project by the end of June.

"There is a GIS conference being held in Denmark in August so I'll probably combine that with a holiday in Europe," she said.

She then hopes to work in biosecurity in the South Pacific or south-east Asia.

"I'd really like to apply the techniques I have learned in countries which have similar types of endemic disease," she added. "There needs to be a more global approach to biosecurity especially in countries that are resource poor."

After completing her undergraduate veterinary science degree Ms Van Hennekeler spent three years as a practising vet. She lived in Fiji for two years while working as a veterinary officer before returning to Australia for a Masters at JCU in 2000.

Note: This story has been adapted from a news release issued by James Cook University

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