Regional wildlife , from snakes and crocodiles, to lions and elephants, to sharks and stingrays, has always played a key role in Survivor games.
"We look at all the environmental factors from the big game to the mosquitoes and the gnats," says Dr. Adrian Cohen, the head of Survivor's medical team.
But it's not only the 16 contestants he's looking after.
"The production is about 400 people, including Americans, quite a number of Australians, local personnel," says Dr. Cohen. "So we're running a little town and we're the little town hospital, if you like."
When not on rounds as Survivor's town doctor, Dr. Cohen is on location for "Eco-Challenge," an expedition race, during which, two years ago, he performed emergency treatment on a competitor impaled by a tree limb.
"I went by four-wheel-drive and ran up the hill to him and found him literally where he lay," recalls Dr. Cohen. "I actually had to put a needle in his chest to relieve the pressure around his lung that was causing it to collapse."
Practicing medicine in the field has led Dr. Cohen to write the book, "Survivor First Aid."
"It seems glamorous when we talk about people putting holes in their chest and the diseases that are life threatening, but the bottom line is that everybody should know first aid," says Dr. Cohen. "Everybody should know how to do those immediate things that will help save a life."
On location for Survivor: The Australian Outback,, Dr. Cohen gave a crash course in how to treat a poisonous snakebite.
In the relative safety of the California coast, he looked back on some of Survivor's adventures in medicine.
He says the biggest medical emergency on the show was an injury by Michael Skupin, who burned his hand after falling into a campfire.
But Dr. Cohen says each installment of Survivor has had its share of illnesses. Contestants on the show have been seriously injured; from bug bites, to digestive problems, to dehydration.
Soon after Survivor: The Amazon contestant Daniel Lue's torch was snuffed, he found himself headed home with malaria.
"It may not be until several weeks later that we find people have come down with malaria, and Daniel is a case in point," says Dr. Cohen. "The treatment is not that complicated, and it is quite commonplace these days, and we expect a good recovery. But it's just an occupational hazard if you want to be a survivor."
Meanwhile, on the next Survivor: The Amazon, the men leave a tribemate behind as they go on a group expedition; an illness hits a woman contestant that shakes up the power at Jaburu; and while the women face a bare camp, the men celebrate with a feast of fish they caught.
To see which occupational hazards remain in the Amazon, watch Survivor: The Amazon tonight on CBS. And watch Friday's The Early Show to see an interview of the latest contestant voted off the show.