Chlamydia isn't the only concern for your average koala. Overdevelopment is threatening the marsupial's habitat, and climate change presents its own risks. But sexual disease is now a driving factor in the animal's path toward extinction.

There may be only 43,000 koalas left in the wild, says The Telegraph, citing recent biological studies. That population is in "dramatic decline," scientists warn.

"I think it will be very hard for anyone to walk away from this data. We have a very high level of confidence that it accurately shows a drastic decline," said the foundation's chief executive, Deborah Tabart.

Large numbers have been killed by an outbreak of chlamydia, a sexually transmitted disease, while others have been affected by loss of habitat due to deforestation and climate change, she said.

Hotter, drier conditions had also reduced the nutritional value of their staple food, eucalyptus leaves, leading to fatal malnutrition.

Researchers visited an area home to about 20,000 koalas a decade ago, the paper reported. They didn't find a single one.

Update:

That link was from back in 2009. This infection fear appears to be a perennial. 

See 2010 edition, and 2011. Rallies to preserve what's left of the declining population have even occurred this month. (More about development pressure than sexual disease, that one.)

And a vaccine may be coming...