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According to an article published in the New York Times, the population of yellow legged frogs in California have decreased dramatically for the last twenty years, at first from human activities. Now a more voracious threat has emerged, a disease called chytridiomycosis, which has decimated existing populations of the frog species. The Vredenburg Amphibian Research Group is trying to change all that, trying to come up with a cure or antidote for the chytridiomycosis. Amphibiaweb explains that chytridiomycosis is “… caused by an aquatic fungal pathogen, Batrachochytrium dendrobatidis (Bd),” and says the disease is relatively new. Chytridiomycosis has caused severe devastation to amphibian species around the world.
“… Bd may be responsible for the greatest disease-caused loss of biodiversity in recorded history. Over just the past 30 years, Bd has caused the catastrophic decline or extinction (in many cases within a single year) of at least 200 species of frogs, even in pristine, remote habitats.”
The disease does not kill every amphibian which becomes infected, but the death rate is very high, and the threat the disease causes to amphibians around the world have caused World Organisation for Animal Health to list the disease on its Wildlife Diseases List. The Vredenburg Amphibian Research Group is headed up by biologist Dr. Vance Vredenburg. Vredenburg told the New York Times that he began studying frogs in the 1990s because he saw the research as applicable to
“… solving some real-world problems, like the biodiversity crisis.” Saying he always liked catching frogs, Vredenburg said when he entered his field that scientists were isolated from the world, “… living and working in a bubble.” Pointing to the devastation caused by chytridiomycosis, Vredenburg said
” … Once your study animals start dying, believe me, you pay attention!”
Characterizing chytridiomycosis as “…the worst case in recorded history of a disease driving vertebrate species to extinction,” The work done by Vredenburg and his team has led to a “… stage structured disease model that may help predict spread of the pathogen in the wild.” The researchers are tracking the disease, and they are also seeking to discover how the disease spreads, a fact that still mystifies scientists around the world. The New York Times reported that Vredenburg is also experimenting with “inoculating” frogs with a bacterium that might help the frogs fight the chytridiomycosis infection. No one is certain how dosing frogs with bacteria helps to fight a fungal infection, but it is thought that colonies of bacteria living on the skin of the frogs helps to block fungal colonies from taking root, according to research on the topic published in 2008. And Vredenburg put the hypothesis to the test, catching and bathing yellow legged frogs in Dusy Basin. The frogs are put into a bath containing the bacteria Janthinobacterium lividum. J. Liv, as it is called for short, is commonly found on the skin of amphibians. After their bacterial baths, the frogs were released back into their environment. After conducting a follow-up in early September, Vredenburg found that all the frogs were infected with chytridiomycosis, but had survived the infection. Said New York Times reporter, Erica Rex,
“… Frogs inoculated earlier in the summer were surviving … all the frogs caught in early September were infected with chytrid. The inoculated animals had the lowest levels of infection.”
According to the Sacramento Zoo, frogs are an important species to humans, mainly because they take the role of “canary in the coal mine.” In other words,
“… the health of frogs is closely linked to the health of the environment. Frogs are extremely sensitive to water pollutants and acid rain. They can be seen as an early warning system of problems that may eventually affect the rest of us. “If chemicals in the water cause mutations and reproductive problems in frogs think what it could be doing to humans, “says Vicky Poole of the National Aquarium in Baltimore.””
Additionally, frogs eat insects, and also are important to medical research. Save the Frogs points out that frogs are also an important animal in the food chain. The San Diego Zoo is attempting to breed yellow legged frogs, which has seen one frog reach maturity. Should the program attain success, the bred-in-captivity frogs would be released to the wilds where the species used to live. Earlier this year, the California Fish and Game Department received a petition urging the Department list all populations of the yellow legged frog as endangered. An analysis conducted by Department employees supported the petition, with a recommendation to list the frogs as endangered. The recomendation was accepted, however, there is a year before the frogs can be listed as endangered, said a news release from the Center for Biological Diversity. The ICUN Red List had identified two populations of California’s yellow legged frogs as endangered in 2008.