Fungus sweeping the world – 04/27/2006

  • November 23, 2013 at 4:57 pm #1181
    Scientists take cue from Noah as killer fungus threatens amphibians

    By John Biemer
    Hi All
    One ask, what is the role of global dimming, as created by
    persistant cirrus clouds (see nasa report)aka CTs and the sharp
    spike in all forms of fungus and other molds.

    Tribune staff reporter
    Published April 26, 2006
    A devastating fungus is sweeping the world, wiping out entire
    populations of amphibians at such a rate that Brookfield Zoo
    biologists are helping pull together a massive “Noah’s Ark” project
    to capture frogs, toads and salamanders and put them in safe places.

    A variety of factors already have combined to cause more than 120
    amphibian species to vanish since 1980, in what one biologist has
    called “one of the largest extinction spasms for vertebrates in

    A third of the world’s nearly 6,000 amphibian species are threatened-
    -their populations weak and susceptible to disease. If they go,
    ecosystems will tilt out of balance and potential medical
    breakthroughs–such as potent painkillers or HIV inhibitors–could
    be lost.

    It is hard to determine how many species have been affected by the
    fungus because they cannot be assessed fast enough, but it has
    factored into most of the recent extinctions and declines, said Bob
    Lacy, the zoo’s population geneticist and chairman of the
    Conservation Breeding Specialist Group.

    That leaves no time for anything but a triage attempt to get some of
    the animals out of harm’s way until this “tragically unique” disease
    can be further studied and countered, he said.

    “It is a race against time, and it’s a matter of months,” Lacy said.

    Among zoologists, some have begun to face questions of which species
    should be saved and why.

    “It’s terrible, I’ve never experienced anything like this,” said
    David Wake, a biology professor and curator of herpetology at the
    University of California at Berkeley, the first scientist to
    officially declare a pattern of global amphibian declines in
    1989. “It’s really an awful prospect.”

    Disease takes hold

    When this fungal disease came along, amphibians the world over
    already faced significant stress from global warming, pesticides and
    herbicides, acid rain and habitat destruction, experts said.

    Some scientists point to them as bellwether animals for the Earth’s
    health. Their slippery, porous skin absorbs moisture around them,
    making them more vulnerable to environmental changes than mammals,
    birds and reptiles with their fur, feathers or scales.

    But chytridomycosis, caused by the chytrid fungus, is adding a
    confounding new level of peril that is pushing many species over the
    brink–even in areas mostly untouched by human hands.

    “This is a totally unusual conservation dilemma–species going
    extinct in a relatively pristine environment,” said Alejandro
    Grajal, Brookfield Zoo’s senior vice president of conservation,
    education and training. “Now we’re basically trying to save as many
    as we can as we try to figure out our next step.”

    Chytridomycosis was first identified in 1998 and is not well
    understood. As it moves around the globe, it has caused massive
    amphibian die-offs in Australia and hit the population of boreal
    toads in the Rocky Mountains. In the Sierra Nevadas, California-
    Berkeley researcher Vance Vredenburg found “piles” of mountain
    yellow-legged frogs dead from the disease two years ago.

    The disease is filtering down Central America–one of the most
    biologically diverse areas on the planet–at a rate of about 17
    miles a year, faster than a frog can hop to the next pond. With
    support from the Houston Zoo, Mauricio Caballero is leading an
    effort to build a field facility in Panama to preserve species, but
    the fungus caught up to his El Valle region before the roof was up.

    “We knew what was going to happen, and now we’re seeing the frogs
    starting to die,” he said after a meeting with other Latin American
    experts Monday in Brookfield. “We weren’t expecting it to hit so
    soon. We were predicting it was going to hit in the rainy season.”

    Scientists race against time

    Now scientists are scurrying to collect frogs and put them in
    temporary tanks in hotel rooms and people’s houses until the
    building’s ready, Caballero said. Plans to save 65 species have been
    downscaled to the dozen or so most endangered–including the
    beautiful, iridescent Panamanian golden frog. The species is a
    cultural icon for its people as the bald eagle is for Americans–
    it’s been depicted in jewelry since pre-Columbian times and is the
    inspiration of local festivals.

    The Brookfield Zoo does not have the proper buildings to warehouse
    amphibians. So zoo experts there are providing training for
    researchers in the field, grant money and helping connect experts
    like those visiting this week from Mexico, Ecuador, Colombia and
    Panama to ensure that the species are collected as quickly and
    efficiently as possible. Zoos that do have the capacity to take more
    amphibians need to do so, too, Lacy said.

    Chytrid fungus is carried in water, but the disease is specific to
    amphibians, invisibly feeding on their skin’s keratin and causing it
    to thicken. The exact mode of death is unknown–it may produce a
    toxin or it may impair the amphibian’s ability to breathe and absorb
    water through its skin.

    How it got around the world so swiftly is also not understood. It
    could have been carried by human travel–or by the global movement
    of ballast water and invasive species. Vredenburg says one
    hypothesis is the fungus always was around–but now amphibians are
    vulnerable to it, like humans suddenly dying of the common cold. One
    theory Grajal cited is it got around with African clawed frogs,
    which were shipped around the world in the 1940s and 1950s for use
    as pregnancy tests after it was discovered that a female injected
    with the urine of a pregnant woman began laying eggs.

    Reasons for hope

    There is some good news about the disease–besides the fact that it
    does not affect humans. Among some amphibian species it seems to
    kill only some individuals. Although scientists do not know how to
    stop the disease in nature, they can treat it in labs. And, so far,
    it is not believed to have reached areas of great amphibian
    diversity such as Madagascar, India and Indonesia.

    There could be even more at stake with all these dying frogs than
    their key roles in the food chain consuming insects and other small
    critters. Scientists say amphibians have great, largely untapped
    medical potential.

    Last October, the Journal of Virology published a Vanderbilt
    University Medical Center study showing that compounds secreted by
    an Australian red eye tree frog’s skin appear to inhibit HIV
    infection. Poison dart frogs long have provided venom used by
    hunters in Central and South America, but pharmaceutical companies
    are researching a compound found in the frogs that could yield a
    painkiller 200 times more potent than morphine.

    The total cost of holding 600 species captive to protect them will
    run about $60 million, Grajal estimated–a relative bargain compared
    to the costs of saving large animals like elephants or pandas.

    “The very preliminary analysis we’ve done shows there’s an
    incredible potential [for medicines], and just because of that it’s
    worth the effort,” he said.

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