KERRY O'BRIEN: Now to the epidemic which threatens Australia's reptile population. At first blush, some of you might rather like the idea of some of the country's deadliest snakes being wiped out. But of course it's not as simple as that.
A highly contagious and deadly disease has been found in a collection of exotic snakes and pythons allegedly smuggled into the country. Authorities now fear the disease could spread to wild populations with devastating consequences.
At risk are not just Australia's unique species but potentially tens of millions of dollars in lost agricultural production. The ABC's science and environment reporter Michael Troy.
GLEN SHEA, ZOOLOGICAL SCIENCES, SYDNEY UNIVERSITY: The disease is invariably fatal, in the long term. It can cause rapid death or it can cause a long, slow agonising death because the animal will stop feeding. It will lose control over itself and won't be able to feed and it will just waste away and die.
MICHAEL TROY: If it is spread into the wild population, how big a threat would it be to our Australian native species?
GERRY SWAN, HERPETOLOGIST: Well, it would be one, they would have no immunity to it, so you could imagine it would be quite disastrous.
MICHAEL TROY: Of the 6,000 reptile species worldwide, 750 are native to Australia. They are a vital part of the ecosystem and have evolved and survived here for millions of years., But now they face a new threat with the discovery of a highly contagious and deadly disease.
KARRIE ROSE, VETERINARY PATHOLOGIST, TARONGA ZOO: Well the two snakes that started this whole event off, were not coiling properly. They didn't seem to have control of the back half of their body. They weren't eating any more and they started to have a bit of a wobbly headshake.
If you turned the snake over on its back, it wasn't able to right itself again.
MICHAEL TROY: Veterinary pathologist at Sydney's Taronga Zoo, Karrie Rose, recently helped confirm wildlife authorities' worst nightmare - that a deadly virus known as inclusion body disease, had eluded strict quarantine measures.
MICHAEL TROY: What's happened to this snake?
KARRIE ROSE: Well, in this view, we can just see the damage that's happened further upstream to the nervous cell tissue, where we've got spongy change or a Swiss cheese effect really, where individual cells have died and all we are seeing is the hole where they used to be.
MICHAEL TROY: These, the first-confirmed victims, were among a collection of 62 exotic reptiles, seized by authorities earlier this year. Recently they were all put down, when it was confirmed, many of them carried the disease.
KARRIE ROSE: It's quite an infectious virus and moves quite readily from one snake to the other with handling -- if you're using the same cleaning instruments in one cage as you use in the next, so strict quarantine is absolutely necessary.
GRAHAM WILSON, NSW NATIONAL PARKS & WILDLIFE SERVICE: This illustrates that what is seen as harmless, can actually have very serious consequences if it is not controlled.
MICHAEL TROY: The NSW National Parks and Wildlife Service is bringing in an American expert on the disease and wants a national approach to contain it.
GRAHAM WILSON: Because at this stage, all we know, is that the disease is in some captive snakes in Australia. I think we have to do everything we can, to make sure it only stays there and doesn't spread more widely.
MICHAEL TROY: In WA, Brian Bush is known as the 'Snake Man'. He travels the State extolling the virtues of snakes.
BRIAN BUSH, SNAKE WRANGLER: They do a tremendous amount of good. I mean, it's analogous to not having birds. We wouldn't be able to utilise snails, grubs, worms, and kitchen scraps as protein.
Snakes conservatively, in an agricultural area, are worth per snake, $350,000 to the local economy, just in mice and rat control. I mean, in agricultural areas the farmers should be throwing them a kiss and appreciating that they're out there.
GERRY SWAN: They do have an image problem with a lot of people. It seems to be diminishing, but they are - reptiles generally - are a very popular pet and are becoming more and more popular in Australia.
MICHAEL TROY: Author and keen snake collector, Gerry Swan, was the first person licensed to keep reptiles in NSW. It's a pastime he says, is now increasing in popularity.
GERRY SWAN: They're not dangerous, they can bite of course, all snakes can bite, but they're not venomous.
MICHAEL TROY: The problem is, the underground trade of illegal, more colourful exotic reptiles, is also booming.
GERRY SWAN: They've really got to face up to the fact that there are exotic reptiles in Australia. There's a considerable number of them and most are held illegally.
GLEN SHEA: In the last decade, the number of people keeping reptiles has increased almost exponentially.
MICHAEL TROY: Glenn Shea's native pet diamond python, 'Spider', often accompanies the scientist to work at Sydney University. The senior lecturer believes hundreds of exotic reptiles have been smuggled in from the US and Europe, where the disease first emerged.
GLEN SHEA: Well they're very easy to hold in a small space. They don't move much during transport.
They don't need regular feeding or watering during transport, so they will survive quite happily, long transport times in small, enclosed spaces.
MICHAEL TROY: While Customs officials have had some success in slowing the illegal trade, it may already be too late to contain the disease, with reports of similar mystery illnesses in collections in Victoria and WA.
MICHAEL TROY: How could it actually escape into the wild?
GRAHAM WILSON: Well, the concern would be, that if somebody had a pet reptile that they chose to release into the wild. Or, somebody had a rehab snake that they'd picked up for care because it was injured and mixed that with some other reptiles that might be incubating the disease.
MICHAEL TROY: Australian snakes are reclusive animals and it will be difficult to gauge whether the disease has spread into the wild. Only a few years ago, a deadly virus attacked many frog species in remote areas.
GRAHAM WILSON: There is an ongoing problem with a disease called frog citrode fungus, which seems to have caused the extinction of several frog species. Australia's reptiles will soon emerge from winter hibernation, and only then, will scientists be able to gauge the impact of this latest disease threat.
GLEN SHEA: Our animals will have effectively no resistance to these diseases coming in.
GERRY SWAN: Well, it's going to upset the whole biodiversity of any area.