Still widely used in genetics and developmental biology research, X. laevis remain popular pets. "This is one of the very cheap pets you might give a five-year-old," Kirksey says. "But people at the pet stores usually don't tell you, 'Hey, this frog's going to live 15 years, and it'll be as big as your hand when it's fully grown.' So a lot of them get thrown in the toilet or let go into streams."
According to Kirksey's research, some frog wholesalers breed and store the animals on a mass scale. "We're talking about hundreds of thousands, if not millions of frogs living on top of each other," he says. And if one frog has a chytrid infection, he says, it’'s likely that all of its tank-mates have it, too.
Evidence does suggest that pet store frogs may be infected. In a study of imported bullfrogs sold live in U.S. food markets, 62 percent tested positive for Bd. Another study found that more than a quarter of amphibians in Japanese pet stores (pdf) may be carrying the fungus. Kirksey says that if chytrid is common in New York City pet stores, he intends to find out which frog wholesalers are moving the fungus around.
"There's no legislation on selling frogs with Bd at this point in time," Schloegel says, and pet wholesalers are not required to test for Bd. Mike Khadavi, a former director of the Amphibian Steward Network who has been collaborating with Kirksey on the project, expects that some pet suppliers may not want to test their frogs because they won't want to spend the money to quarantine and treat the frogs.
The U.S. Fish and Wildlife Service is considering legislation to prevent the importation of Bd. The act would classify amphibians infected with chytrid as "injurious wildlife" and would require traders to certify that their amphibians are chytrid-free before they could import the animals into the country or transport them across state lines.
"The pet industry is actually very aware of the problem, and they're doing a lot to minimize the threat," Schloegel says. In 2007 the Pet Industry Joint Advisory Council launched their "Bd-Free" campaign, which aimed to educate pet industry personnel and consumers about the dangers of the fungus.
Still, not all pet traders are aware that there's a problem. When Kirksey, Khadavi and I visited a locally owned pet shop in Brooklyn, the owner said he didn't know anything about the fungus, but he didn't object to having his frogs tested. "Basically we have these little Q-tips," Kirksey explained, "and we can run it on the frog and test it, and if the frog does have the disease, then there's a way to cure them of it"—namely, with inexpensive antifungal baths.
"If the frogs were tested on a regular basis to make sure they are disease-free, I think that would solve the problem," Schloegel says. "There needs to be a little more oversight in monitoring the disease."
Harris says it is particularly important to prevent the spread of Bd in light of recent research, which suggests that the deadly fungus arose when two non-virulent strains of fungus mated. By limiting the movement of the fungus, the pet industry may be able to prevent a similar such unholy union from occurring again in future, he says.