By SUSANNE RUST
srust@journalsentinel.com
It's the frog version of the Ebola virus: a disease so rapacious it kills nearly every croaker it encounters.
Steam-rolling its way south through Central America and across the Caribbean, the fungus known as chytrid is killing millions of frogs - wiping out entire species and tipping ecosystems out of balance as these amphibious keystone species are expunged from existence.
And while scientists don't know how to stop this fungal fury, they are - with help from three Milwaukee County Zoo employees - trying to bide time by collecting, disinfecting and housing the survivors, in hopes that a few will pull through and someday recolonize the cloud and montane forests the fungus has plundered.
The fungus, which probably originated in Africa, kills by thickening the frogs' skin, such that the inward flow of oxygen and outward expiration of carbon dioxide is restricted - in effect, suffocating the animal.
"When we find frogs who are about to die, they are standing on the very tips of their toes, straining to expose as much skin as possible" to breathe, said Craig Berg, the zoo's reptile and aquarium curator.
Berg and two other frog experts at the zoo - Craig Pelke and Shawn Miller - are helping researchers in Panama salvage the few remaining frogs, while simultaneously studying frogs from Grenada, where the fungus has yet to hit.
They hope that by understanding the behavior and biology of the frogs, as well as figuring out how to get them to breed in captivity, they might someday reclaim the forests for the frogs.
"It's kind of like what AIDS was in the 1980s," said Berg, referring to the research community's urgent response to a new global threat. Indeed, just as doctors and epidemiologists raced to answer the most basic questions about HIV and AIDS - such as, how does the disease travel? Where does it live? And how did it get here? - so too are herpetologists and zoologists in the case of chytrid, pronounced (KIT rid).
1938 specimen
Zoological epidemiologists say the earliest known evidence of the fungus can be found on a 1938 preserved specimen of a South African clawed toad,
Xenopus laevis. Like the fruit fly or white mouse,
Xenopus frogs are ubiquitous features of molecular biology laboratories around the world.
Frogs are critical parts of food chains. Not only are they eaten by larger animals such as birds and mammals, they also consume insects such as mosquitoes.
Researchers believe the fungus was probably endemic to South Africa but caught a ride on
Xenopus exports as the demand for these frogs increased worldwide. Escapees and the victims of dissatisfied pet owners were then introduced into the wild, spreading the infectious fungus to the continents of Australia, Asia, North America and South America. Water dumped from
Xenopus terrariums may have also led the spread.
To date, the fungus is known to have exterminated as many as 120 frog species, and it threatens many more.
It was first spotted in Panama in the spring of 2005, after leveling frogs in the upper-altitude forests of Mexico and Costa Rica - including Costa Rica's harlequin frog and golden toad.
Panamanian researchers had seen the fungus approaching, according to Pelke. In anticipation of the arrival of the fungus, researchers, with the help of experts at the Houston Zoo, began to build a facility to house the frogs in 2005, with hopes of having it up and going by 2007.
The idea was that once the building was complete, researchers, curators and volunteers from around the world would arrive, collect frogs and move as many as they could into the new center.
But the fungus came knocking one year earlier than anticipated, catching researchers unprepared.
So, frog experts scrambled, calling on as many volunteers as they could to collect as many frogs and salamanders (which are also susceptible) as they could, which they temporarily housed in a hotel near El Valle, Panama - where they'll remain until the amphibian conservation center facility is completed.
"This is really a stop-gap measure or an emergency response measure," said Peter Rieger, a curator at the Houston Zoo. "We are getting them out of harm's way."
Dim future
Berg and Pelke arrived as part of this mission. They spent their days and nights looking for frogs as well as insects - searching for invertebrate sustenance for the frogs.
They realize that the future for these frogs looks dim. If the scientific community can't figure out how to eradicate the fungus from these animals' environment, a reintroduction of the saved frogs isn't going to do a thing.
According to Paul Crump, a curator at the Houston Zoo, even trying to figure out how this fungus travels has been difficult. "Is there frog-to-frog transmission? Does it travel on insects? On the soles of shoes?" he said.
It's the answers to these questions that herpetologists are scrambling to answer in order to save the frogs.
The other hope is that somebody will soon figure out how to get rid of the fungus - to clean the frogs' environment and let them go home.
But while they're waiting, Berg is making sure that the frogs he's most intimately acquainted with - the Grenada frog - will fare the onslaught safely, if and when the fungus hits their small Caribbean island home of Grenada.
He's collected eight Grenada frogs, which he's keeping in the basement of the Aquatic and Reptile Center at the zoo. Here, Miller, Pelke and Berg are maintaining the frogs in terrariums and trying to figure out how to make them feel at home.
They're off to a good start: A female Grenada frog under their keep laid a clutch of eggs earlier this year. Although the clutch never hatched, it was the first time this frog had ever produced eggs in captivity.
Threatened Frogs Get Reprieve in Milwaukee
Frog Disease
It's kind of like what AIDS was in the 1980s. 
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