Bat experts study flowering gums and infectious diseases link in Qld

International bat ecologists have arrived in Queensland to study the impact of changes in flowering eucalypts on bat populations and the emergence of infectious diseases such as SARS, Hendra virus and Ebola throughout the world.

The researchers from 10 academic institutions have received a $2.1 million United States National Science Foundation grant to study how the impact of humans influences the distribution of infectious diseases from animals to people.

Four Queenslanders and more than 70 horses have died from Hendra virus, while there were 27 "probable" cases of the pneumonia SARS - severe acute respiratory syndrome - in Australia when the 2003 worldwide outbreak happened.

In the case of Hendra virus, the big catalyst appears to be changes in the winter flowering of eucalypts, forcing bats to locate in new colonies, often closer to humans.

The international researchers are working with Griffith University, which will lead the field research side of the project.

They want to study the cascading impact of biological changes leading to a spread of bat-borne viruses.

"Changes in climate and deforestation of winter habitat of flying foxes creates periodic food shortages for the bats," Griffith University's lead researcher, veterinary disease ecologist Dr Alison Peel said.

"In search of more reliable food sources, they often end up roosting in towns and cities," she said.

Dr Peel said bat populations were not increasing in size.

"Many people think flying foxes are increasing in numbers, but they are not," Dr Peel said.

"It's just that instead of being out in the bush, flying foxes are now living near our houses and feeding on trees in our gardens and weeds in urban land," she said.

Problems can occur when bats roosting near urban areas excrete the potentially fatal Hendra virus, which is carried in the bats' reproductive fluids and urine.

The link to humans is still unclear, however this is the scenario as it is reported on the Queensland Government's Department of Primary Industries' website.

"Several hundred people have been exposed to Hendra virus infected horses but have not been infected. However, seven people have been confirmed to have Hendra virus following high levels of exposure to infected horses. Four of these people died, the most recent in 2009," the website outlines.

Horse owners are at risk of Hendra virus because horses graze under trees on the fringe of cities and towns where relocated bats roost.

The project's main researcher is Raina Plowright, an Australian who now lives in Montana in the United States.

Dr Plowright believes by improving the balance of species in the forests, the bats will no longer need to roost so closely to humans.

"In this case, potential solutions benefit the health of the forests, the health of the bats, the health of livestock and the health of humans," Dr Plowright said.

"This whole cascade of events could potentially be solved if we can restore their winter habitat and draw the bats out of the cities."

University of New South Wales bat ecologist Dr Peggy Egby said the project team wants to encourage flowering gums in Australia's forests.

"We are working with private landowners and communities to restore critical winter-flowering species into existing programs of habitat regeneration and restoration," Dr Egby said.

She said by improving the winter flowering of eucalypts, an important ecological function of bats could be restored.

"Flying foxes spread pollen and seeds from native trees over much greater distances than birds and insects, connecting fragmented forest patches," Dr Egby says.

"The animals that feed in urban areas aren't performing this vital function and we need to try and reverse this."

The project team wants to develop a flow of scientific information that covers changes in winter flowering, changes in bat roosts and information on Hendra virus vaccinations for horses.

They are completing their research in Australia, where it is easier to operate than in some African countries, Dr Plowright said.

"We're seeing the emergence of more and more infectious diseases from bats, such as SARS and Ebola, but they are emerging in countries in Africa and Asia where it is difficult to do detailed multidisciplinary studies" she said.

"If we could identify the underlying environmental drivers, as we are trying to do for the flying foxes in Australia, we can potentially reverse and eventually prevent outbreaks by getting to the root cause of this public health problem."

This story Bat experts study flowering gums and infectious diseases link in Qld first appeared on The Sydney Morning Herald.