Biologists continue to seek answers on outbreak of deer disease.
Wildlife biologists from throughout Western Oregon are gathered in Salem today, brainstorming about blacktail deer conservation.
Meanwhile, 25 miles away at E.E. Wilson Wildlife Area, construction is under way on pens to hold 30 deer that soon will be trapped for a three-year, $230,000 research project on deer disease.
These are the latest developments in the continuing saga of Deer Hair Loss Syndrome (DHLS), an outbreak that coincides with a downward spiral in West Coast blacktail deer populations. First noted in Washington in 1995, DHLS has since spread throughout Western Oregon and Northern California.
Hunter success in Western Oregon is now less than half what it was 15 years ago - a sure sign the population has plummeted.
The Oregon Fish and Wildlife Commission moved last fall to ease hunting pressure on blacktail by shortening the 2004 rifle season, and by eliminating thousands of antlerless deer tags. It also asked biologists to develop additional conservation measures for possible use in 2005.
Whatever the biologists come up with this week will be presented to the commission in February. It will be outlined locally at the Feb. 18 meeting of the Oregon Hunter's Association at 7 p.m. in the upstairs meeting room of the union hall at 1116 S. "A" St., Springfield.
Deer Hair Loss Syndrome is not a typical animal disease, which flares up for a year or two then fades away. It's not even a disease in the usual sense of being caused by bacteria or viruses because deer suffering from hair loss syndrome are infested with lice, not germs.
The lice drive blacktail into an antsy state of distraction, in which the deer constantly bite, scratch with their hooves and rub against trees or other objects until, eventually, large patches of hide are rubbed bare and exposed to the elements.
It's a state in which the deer become undernourished because, as biologist Bill Castillo explained during a recent talk to the Oregon Foundation for Blacktail Deer, "They spend all their time scratching instead of feeding."
Deer have always had lice, Castillo said, "and we've never seen this kind of impact before."
So biologists aren't certain whether the lice are the cause of the die-off, or a symptom of some larger, more insidious problem.
Wildlife laboratories so far have found no evidence of "toxicity," which should be present if the hair loss were caused by, say, herbicides sprayed on forestlands. Nor, said Castillo, have any suspect viruses been found in infected deer.
So researchers have been looking more closely at the parasites - the lice.
"We're coming to the conclusion there's a strong possibility these lice may be an exotic, unclassified species of the genus Damalinia," a lice typically found on "Old World" ungulates, such as Axis, Sika and Fallow deer, Castillo said.
Such a finding would invite speculation that the lice were somehow introduced into the wild deer population via exotic deer imported by game ranchers.
"That's certainly a possibility," Castillo said.
"Every animal moved around is carrying some passengers, and most are pretty host-specific."
But speculation is all that it can be at this point, because scientists don't yet know enough about DHLS.
The study to be conducted by Oregon State researchers will hopefully answer questions about how DHLS is transmitted - such as whether the lice can migrate from one deer to another without physical contact between the two deer.
Researchers also want to know if Eastern Oregon's mule deer population is susceptible, so several mule deer will be inoculated with lice. And whether deer that survive their first exposure to DHLS develop any immunity or resistance.
"There's a lot of basic questions we hope to determine the answers to," Castillo said.
Hunters can only hope those answers aren't too long in coming.
Mike Stahlberg can be reached at firstname.lastname@example.org.
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|Publication:||The Register-Guard (Eugene, OR)|
|Date:||Jan 15, 2004|
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