More on Elk deaths in Wisconsin – 06/11/2005

  • October 23, 2013 at 2:32 am #703

    from arufon – ‘

    LARAMIE, Wyo. — University of Wyoming scientists will attempt to
    identify a toxin in lichen that resulted in 450 elk deaths last year,
    and possibly determine the safety of eating game that consumed the

    A five-member team from UW’s Department of Veterinary Sciences
    launched the study, which will also attempt to determine whether
    cattle and sheep can safely graze in lichen-infested areas like the
    Red Rim of south-central Wyoming where the massive die-off occurred.

    A grant from the College of Agriculture will pay for researching the
    lichen Xanthoparmelia chlorochroa and which compounds in the plant
    led to the elk deaths about 15 miles southwest of Rawlins.

    “Without the identity of the toxin, there is no practical way to
    evaluate the toxicity of X. chlorochroa under various environmental
    conditions to see if temperature, moisture or ultraviolet radiation
    influences its toxicity,” said the lead investigator, professor Merl
    Raisbeck of the Veterinary Sciences Department, which is under the
    College of Agriculture.

    Other members of the team are assistant professor Todd Cornish,
    associate professor Don Montgomery, graduate student Becky Dailey and
    Assistant State Veterinarian Walter Cook.

    The team will test the lichen’s effect on sheep and will be carried
    out for about two years at the State Veterinary Laboratory and UW’s
    Livestock Center west of Laramie.

    Researchers were alerted to the problem in February 2004 when hunters
    searching for coyotes discovered two cow elk unable to stand.
    Eventually, an estimated 450 elk lost strength and coordination and
    either died or were humanely destroyed.

    Testing eventually ruled out metals, toxins and environmental
    poisons, according to the project abstract prepared by the

    A book published in the 1960s on poisonous plants raised the
    possibility that lichen was the cause.

    “Eventually, we were able to identify the causative agent,” the
    abstract states. “As is often the case, one answer created many more
    questions. Within 24 hours of the release of our findings, wildlife
    managers and ranchers were demanding answers to the questions that we
    hadn’t yet considered.”

    The scientists were asked about the safety of eating animals that had
    ingested the plants and whether cattle and sheep can safely forage in
    areas containing the lichen.

    They were also asked how a plant thought to be excellent forage could
    poison such a high number of elk. Some wondered if there was a way to
    predict similar events.

    Raisbeck said the concerns are legitimate because the lichen is found
    in many areas throughout southern Wyoming. But he said until the
    identity of the toxin is known, scientists have no way to diagnose
    poisoning in smaller episodes or gauge the extent of the problem
    across the region.

    The findings could also have ramifications for the food and drug
    industry since lichen is widely marketed as a nutritional supplement,
    the abstract said.

    “As such, it is completely unregulated by the usual food- and drug-
    safety agencies, yet evidence is piling up that lichen products have
    already resulted in numerous human deaths, and the National
    Institutes of Health is showing interest in the health effects of so-
    called ‘health foods,'” the abstract stated.

    One possible toxin contained in the lichen is usnic acid, which is
    known to cause liver damage in humans and mice.

    There is conflicting evidence that usnic acid can cause a syndrome
    similar to what was exhibited by the Red Rim elk, but it has never
    been tested in ruminants, the researchers said.

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