SCIENCE NEWS
Tuesday, November 17, 2009
The koala, Australia's star symbol, is dying of stress.
Koalas live in the rolling hills and flat plains where eucalyptus trees grow, because they need the leaves for both food and water. But as people move in, koalas are finding fewer trees, researchers say. As a result, the stress is bringing out a latent disease that infects 50 to 90 percent of the animals.
"Koalas are in diabolical trouble," says researcher Frank Carrick, who heads the Koala Study Program at the University of Queensland in Australia. "Numbers show that even in their stronghold, koala numbers are declining alarmingly."
The culprit is chlamydiosis, a virus that breaks out in koalas in times of stress -- like cold sores do in humans -- and leads to infections in the eyes and urinary, reproductive and respiratory tracts. It can cause blindness, infertility and death.
Deborah Tabart, chief executive of the Australian Koala Foundation, says the koala needs to be classified as a threatened species, with policies directed at preserving its habitat. The United States already considers the koala a threatened species. The Australian Koala Foundation estimates there are fewer than 100,000 koalas left in Australia, down from the millions at the time European settlement of the continent started in the late 1700s.
Although Carrick thinks the numbers are slightly higher, regional counts by scientists and state governments show a huge drop. There's clear evidence that some local populations have gone extinct because of chlamydial disease, Carrick said. A 2008 survey of the so-called Koala Coast area, where the animal is most abundant, shows the population dropped 64 percent, from more than 6,200 in 1999 to about 2,800. Car accidents and dog attacks killed many koalas, but the report blamed about 60 percent of the deaths on disease.
-- Associated Press
