Washington Hunter
Well-known member
By ROBERT WAGGENER
UW News Service
LARAMIE -- University of Wyoming researchers are looking for the “missing link” in the deaths of about 350 elk in early 2004 in south-central Wyoming.
This month they launched a second major study to determine what caused some of the elk using the Red Rim/Daley Wildlife Habitat Management Area southwest of Rawlins to lose their leg strength and coordination. They died of starvation or predation, and many required euthanasia.
UW College of Agriculture scientists, in collaboration with the Wyoming Game and Fish Department, previously determined the elk consumed Xanthoparmelia chlorochroa, a free-living lichen common in many parts of the state. They identified usnic acid, which is linked to liver damage in humans, in samples of the lichen collected from the Red Rim.
Merl Raisbeck, a faculty member in the College of Agriculture’s Department of Veterinary Sciences, said his team believes usnic acid is only partly responsible for the elk deaths.
According to experiments conducted in the Wyoming State Veterinary Laboratory in Laramie, which is managed by the veterinary sciences department, the amount of acid in lichen collected from the area could not have been solely responsible for the poisonings, Raisbeck said.
"It is probable that usnic acid acted in synergy with some other, as yet unidentified, toxin ... to cause the specific syndrome seen in the field,” Raisbeck said.
A common misconception is that merely identifying a given compound in a toxic food somehow proves it is poisonous, he said. Other compounds, harmless by themselves, may act synergistically to become quite toxic in combination.
“One question we hope to address is the identity of the missing link. This is important to more than just Wyoming’s livestock and wildlife. Xanthoparmelia species are marketed as everything from herbal ‘Viagra’ to weight-loss supplements on the Web,” he said.
The U.S. Food and Drug Administration warns that usnic acid is linked to liver damage.
Raisbeck said the Department of Veterinary Sciences received two grants totaling about $70,000 from the Wyoming Wildlife/Livestock Disease Partnership and the Wyoming Agricultural Experiment Station to characterize the pathology of X. chlorochroa poisoning.
“Understanding what the plant does in various organs will likely give us some clues as to what other toxin is present in the lichen. This study will hopefully also reveal subtleties that will allow us to differentiate lichen poisoning from other forms of paralysis and muscle necrosis in future field studies,” he said.
Becky Dailey of Cheyenne, a graduate student in the veterinary sciences department, was involved heavily in the initial research, and this month she started the first in a series of experiments to identify the missing link.
Also involved in the experiments are associate professor Donald Montgomery and laboratory technicians Roger Siemion and Marce Vasquez of the veterinary sciences department and professor emeritus Jim Ingram of Colorado State University.
John Roach, a research chemist with the U.S. Food and Drug Administration in College Park, Md., contributed to the earlier experiments.
“This was one of the most challenging disease investigations the Wyoming State Veterinary Laboratory has ever had to do, particularly given the media attention, the large-scale nature of losses and the involvement of elk,” said Donal O’Toole, director of the laboratory and head of the Department of Veterinary Sciences.
“It was in fact a good ‘trial run’ for us to deal with an animal disease emergency like this, and to work closely with other agencies, particularly personnel in the Wyoming Game and Fish Department," he said.
Game and Fish has continued to monitor the 50-square-mile die-off area but has found no evidence of a replay.
“It was unusual for that many elk to be in the area,” said Game and Fish information officer Jeff Obrecht, referring to the 2003-04 winter.
“Crusted snow drove the elk from their traditional wintering range on the Atlantic Rim, and they were enticed to the bare ground they saw to the north. We believe they ingested excessive amounts of the lichen because the extended drought had left grass in short supply,” Obrecht said.
UW News Service
LARAMIE -- University of Wyoming researchers are looking for the “missing link” in the deaths of about 350 elk in early 2004 in south-central Wyoming.
This month they launched a second major study to determine what caused some of the elk using the Red Rim/Daley Wildlife Habitat Management Area southwest of Rawlins to lose their leg strength and coordination. They died of starvation or predation, and many required euthanasia.
UW College of Agriculture scientists, in collaboration with the Wyoming Game and Fish Department, previously determined the elk consumed Xanthoparmelia chlorochroa, a free-living lichen common in many parts of the state. They identified usnic acid, which is linked to liver damage in humans, in samples of the lichen collected from the Red Rim.
Merl Raisbeck, a faculty member in the College of Agriculture’s Department of Veterinary Sciences, said his team believes usnic acid is only partly responsible for the elk deaths.
According to experiments conducted in the Wyoming State Veterinary Laboratory in Laramie, which is managed by the veterinary sciences department, the amount of acid in lichen collected from the area could not have been solely responsible for the poisonings, Raisbeck said.
"It is probable that usnic acid acted in synergy with some other, as yet unidentified, toxin ... to cause the specific syndrome seen in the field,” Raisbeck said.
A common misconception is that merely identifying a given compound in a toxic food somehow proves it is poisonous, he said. Other compounds, harmless by themselves, may act synergistically to become quite toxic in combination.
“One question we hope to address is the identity of the missing link. This is important to more than just Wyoming’s livestock and wildlife. Xanthoparmelia species are marketed as everything from herbal ‘Viagra’ to weight-loss supplements on the Web,” he said.
The U.S. Food and Drug Administration warns that usnic acid is linked to liver damage.
Raisbeck said the Department of Veterinary Sciences received two grants totaling about $70,000 from the Wyoming Wildlife/Livestock Disease Partnership and the Wyoming Agricultural Experiment Station to characterize the pathology of X. chlorochroa poisoning.
“Understanding what the plant does in various organs will likely give us some clues as to what other toxin is present in the lichen. This study will hopefully also reveal subtleties that will allow us to differentiate lichen poisoning from other forms of paralysis and muscle necrosis in future field studies,” he said.
Becky Dailey of Cheyenne, a graduate student in the veterinary sciences department, was involved heavily in the initial research, and this month she started the first in a series of experiments to identify the missing link.
Also involved in the experiments are associate professor Donald Montgomery and laboratory technicians Roger Siemion and Marce Vasquez of the veterinary sciences department and professor emeritus Jim Ingram of Colorado State University.
John Roach, a research chemist with the U.S. Food and Drug Administration in College Park, Md., contributed to the earlier experiments.
“This was one of the most challenging disease investigations the Wyoming State Veterinary Laboratory has ever had to do, particularly given the media attention, the large-scale nature of losses and the involvement of elk,” said Donal O’Toole, director of the laboratory and head of the Department of Veterinary Sciences.
“It was in fact a good ‘trial run’ for us to deal with an animal disease emergency like this, and to work closely with other agencies, particularly personnel in the Wyoming Game and Fish Department," he said.
Game and Fish has continued to monitor the 50-square-mile die-off area but has found no evidence of a replay.
“It was unusual for that many elk to be in the area,” said Game and Fish information officer Jeff Obrecht, referring to the 2003-04 winter.
“Crusted snow drove the elk from their traditional wintering range on the Atlantic Rim, and they were enticed to the bare ground they saw to the north. We believe they ingested excessive amounts of the lichen because the extended drought had left grass in short supply,” Obrecht said.
