Wednesday, August 28, 2013

Ohio monitors - and prepares for worst - for CWD in the state's deer herd

As Ohio awaits its possible turn as the next place where chronic wasting disease (CWD) shows up in the deer herd, state scientists have already mapped out a defensive strategy.
That pro-active plan first and foremost will include an aggressive containment policy surrounding a six-mile radius where the disease is detected.
Ohio may not have long to wait, either, as the neighboring states of West Virginia and Pennsylvania both have scored CWD infections, though in limited areas.
But, yes, might as well expect that CWD will eventual raise its ugly head here, says the Ohio Division of Wildlife's white-tail deer management administrator.
“There are a couple of camps on opinions regarding CWD,” says agency wildlife biologist Mike Tonkovich. “Some biologists believe it's always existed, but that raises the question of why we haven't found it in the environment.”
In answering his own question Tonkovich responded by saying that perhaps scientists may need to start rooting around for soil samples and not just pawing through the brains of dead deer.
“Until CWD is found in a disease-free area, the camp that believes it was always present will have few 'campers,' ” Tonkovich says. “Point is, people may already be sifting through the soil but I'm not aware of any such work.”
Even so, Tnkovich says “CWD may already be here in Ohio.”
Again, to answer his own musings - at least partially, anyway - Tonkovich says there are at least two potential pathways for CWD's entry. That arrival might come either by (as scientists are fond of saying): “Walk or by truck.”
The first expression means an infected animal may wander into the state on its own. The second scenario would be the inadvertent delivery an infected animal via truck to a captive deer-breeding farm or else a high-fence big-game hunting operation.
“With more than 700 captive cervid facilities in the state, Ohio likely sees its share of both intrastate and interstate commerce and movement of animals,” Tonkovich says.
Then too, Tonkovich says, a lone hunter who unknowingly kills an infected deer or an elk out-of-state and then returns to Ohio that person could become the disease's gatekeeper.
For one very simple reason. If this hunter were to arrive back home with an infected critter intact he then could spread or introduce CWD by improperly discarding through burial the hide, head or other potentially prion-contaminated parts.
Since prions are not only genetically non-living entities but extraordinarily persistent little buggers they can exist in the soil for equally extraordinarily long periods of time.
Thus, prions are ticking time bombs.
Unless, of course, the CWD prions are already here in Ohio and going about their sordid work.
Prions are pretty much considered the dirty player in the CWD drama, too, says Tonkovich.
In the short version of what constitutes a prion, science says it is a mutated protein. Make that – and this is important – a “thing” with no DNA or RNA to give it life.
Still, prions are functional, permitting themselves in a complex fashion somehow to replicate themselves.
Then again, even among scientists the exact role of prions in CWD remains open to debate; whether they are the cause of the disease or possibly just a by-product symptom.
Regardless, the CWD disease focuses its attention on the brain. And as the number of prions in the brain increases the organ begins to develop a Swiss-cheese- or sponge-like structure.
CWD is always fatal. Nor is there a known cure.
Yet while CWD is bad business for elk, deer, moose and such, there is scant to no evidence that this particular “transmissible spongiform encephalopathy” (TSE) disease can invade the human brain. With one important caveat.
Virtually every biologist, physician and scientist cautions against eating certain parts of an infected animal or potentially infected animal. Among those parts would include any component of an animal's central nervous system.
Regardless, Tonkovich notes, the Wildlife Division is working closely with other states as well as internally with other Ohio agencies in trying to get a grip on any potential CWD infestation.
The last thing Ohio wants is to join the roughly 17 or so other states and two Canadian provinces where CWD is known to exist in either captive or wild deer and-or elk.
To that end for each of the about 10 most recent years the Wildlife Division has swept up from 400 to 500 deer for laboratory sampling of CWD.
All are road-killed deer, for a particularly interesting and scientifically sound reason as well, says Tonkovich.
Call it the “zombie-fication” of CWD, if you will.
Since a deer that has lost at least some of its brain power to CWD is more likely to become a road-kill statistic than a healthy, alert deer, those are the animals the Wildlife Division seeks for testing purposes, Tonkovich says.
“Imagine losing part of your brain function,” Tonkovich says. “If we see a deer acting strangely it will go a lab.”
As to whether the sampling of roughly 500 road-kill deer annually is sufficient to detect a CWD outbreak, Tonkovich says the figure is more than enough to get the job done.
In terms of Ohio's on-going look into CWD and its current action/response plan, that course is laid out all business-like, adds Tonkovich.
Chiefly if CDW is found than the state will impose a six-mile radius (113 square miles) containment zone around the location of the proven CWD-infected animal.
The state would then go in, employ a strategy to cull additional animals as well as require hunters to check-in their deer. These deer bodies (heads, really) would undergo laboratory testing for CWD.
Also, within that 113 square mile containment zone, the use of bait to attract deer would no longer be legal.
But likely just within the containment zone, though, says Tonkovich.
The reason being is that the statewide deer-bait-ban horse bolted out the barn door years and years ago, Tonkovich says.
“It would be very, very difficult to administer and enforce a statewide ban today,” Tonkovich said.
Even so, Tonkovich also says, no need exists for scientists – much less, hunters - to run in circles, scream and shout about CWD either now or in the possible/likely future.
Indeed, several states where CWD is known to exist are even backing off the throttle on how they approach the problem.
That is because the disease appears to be slow to spread, and as often as not scares the be-jabberers out of hunters far beyond any actual threat to either a state's deer herd or human health.
And with every CWD-infected state and province now focused on controlling the number of does - plus the employment of increasingly knowledgeable containment game plans - a better understanding of the disease, its consequences and management strategies are ever-evolving, says Tonkovich.
In short, says Tonkovich, a sense of some “CDW fatigue” is beginning to set in with hunters and biologists alike.
“I suspect that at some point we'll be studying this chapter in our deer-management history classes,” Tonkovich says.
- Jeffrey L. Frischkorn

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