Elko Daily Free Press 5-23-10

No confirmed disease link between wild, domestic sheep

ELKO - In December 2009, Nevada Department of Wildlife biologists confirmed bacterial pneumonia had infected Rocky Mountain bighorn sheep populations in both the Ruby Mountains and East Humboldt ranges. Nevada is not alone in this situation, as eight other disease events in four other Western states have been identified and are currently ongoing.

The agency responded immediately and enacted efforts in an attempt to mitigate the situation. NDOW personnel treated some of the sick animals with antibiotics and an anti-inflammatory agent to see if this would help the sheep recover from the disease.

"Draxxin, a broad spectrum antibiotic which is manufactured to treat pneumonia, was delivered to over 65 animals between the two mountain ranges," said Dr. Peregrine Wolff, NDOW veterinarian. "Biologic samples from over 75 animals were also taken and sent to Washington Animal Disease Diagnostic Laboratory for analysis."

"We have now documented over 135 dead sheep between the two mountain ranges," said Caleb McAdoo, NDOW game biologist for the Ruby Mountains and East Humboldt Range. "Unfortunately, the number continues to rise."

The Department has taken an extremely active stance in responding to the disease outbreak. The efforts have included administering an antibiotic, conducting ground surveys and necropsies, and outfitting sheep with radio-telemetry collars and ear tags for follow-up.

"We have also taken vegetation and soil samples to see what role micro-nutrients may be playing in the die-off," explained Mcadoo. "We are trying to look at all of the variables that could be playing a role in this disease event to further our knowledge to help prevent future events like this."

The possibility of domestic interaction with the wild sheep and goats has come into question, but McAdoo said there have been no confirmations of interaction in either area and that NDOW is handling the situation as such.

"Even though portions of the Ruby Mountains do fall within an active sheep allotment, we are not just assuming that domestic interaction is the cause of this event," said Ken Mayer, director of NDOW. "NDOW knowingly re-introduced bighorn sheep into the area in 1989 with no consequential exceptions or changes to sheep management in adjacent allotments."

Larry Gilbertson, game division chief, said, "NDOW has no intentions to use wild sheep to displace domestic sheep allotments through regulation or government process." Gilbertson added that NDOW will continue to work cooperatively with operators to minimize conflict.

"We are very pleased with the approach the Department of Wildlife has taken with regards to this disease event," stated Meghan Brown, Executive Director of the Nevada Cattleman's Association. "They (NDOW) have been openly communicating to us all along the way and have been extremely objective in their approach."

McAdoo expects to continue to find carcasses of sheep affected by the disease event and is predicting that upwards of 80 percent of two herds will be affected. Tracking the animals and studies of the different variables will be ongoing. NDOW will continue the data collection process over the next few years and will be trying to learn as much as possible from this tragic event.

"Unfortunately, there is no known cure, treatment or protocol for pneumonia in bighorn sheep," said McAdoo, "but we are going to use the data collected from this disease event to assist in any future outbreaks we may have."