Concerned human researchers across the globe have been working to find out what’s killing such high numbers of frogs, and they may have found another piece of the puzzle, one that, unlike pollution and increased UV radiation levels, is not the fault of humans. Or is it?
It all started at the National Zoological Park in Washington, DC, when a veterinarian noticed an unusual colony of round cells growing in the skin of a group of arroyo toads. Soon other zoos, laboratories and aquariums had noticed infections like this in their frogs and toads as well. This infection was found to be a new type of fungus; nobody knew where it came from or how it was spread. By 1998, it had been found in 10 species of frogs and toads in 10 different locations in Australia, 7 species in two places in Panama, a species of toad in southern California, and 6 species of frogs in 4 American zoos and aquariums.
Nobody’s quite sure why the fungus kills frogs; the most likely possibility is that the fungus, which grows in the skin of the infected toads and frogs, suffocates or dehydrates them, since amphibians, unlike humans, breathe and drink through their skin. Another possibility is that the fungus makes some kind of toxin that poisons the frogs.
Another mystery is where the fungus came from. How did it manage to show up on two different continents, on opposite sides of the globe, at the same time? Some people think that the fungus may have been lingering in the frog population for a long time, but not killing them until the frogs became weakened by UV radiation and pollution. Others suspect that researchers may have carried it from one continent to another, infecting the local frog populations as they study them. Researchers are now observing careful decontamination processes when handling amphibians: mud should be removed from clothing, traps, and vehicles, and equipment cleaned using a 70% ethanol solution, and rubber gloves should be worn when handling frogs. Hopefully this can stop the spread of disease.