disease updates

Last winter our outfit started a 5-year research project of capturing elk on a feedground, testing the cows for brucellosis, and slaughtering any who were found to have antibodies to the disease. Trapped 431 elk, of which 263 were cows, of which 58 had to be slaughtered. The initial words of wisdom from the boss in charge, when discussing the trapping operations?

"Elk behavior may be unpredictable."

Really. Who'd'a guessed?

His second point of wisdom?

"Weather may be a factor."

Yeah, I'll buy that. For anything in this state in winter.

Have I ever expressed wonderment about the word "co-mingling"? I mean, do you know what it means?

It means "mingling".

Really. I don't know why professionals insist on using that word, but they do. Sort of like "utilizing" for "use".

Of course, we learned months ago that humans love elk meat, even if they know it is infected with brucellosis (Which humans can catch. It's called undulant fever.). Folks were lining up at two in the morning, like for a Star Wars opening, for the free giveaway of 8,900 pounds of meat from these elk. Now, we did this to try to eradicate brucellosis from the wild elk herd, not for the meat. But I did the math, just the same.

Project cost $336,000, and yielded 8,900 pounds of elk meat, so that's just under $38 per pound.

And worth every penny if this works.

We learned grizzly bears catch brucellosis, too. In fact, most of the ones tested have it because, hey, they spend the spring trying to eat elk calves and fetuses, which is the best way in the world to catch the bacterium.

But bears are tough. Doesn't seem to bother them at all. (But who went up to ask, I wonder?)

One of the initial concerns with the culling operation was that elk that had been experimentally inoculated for brucellosis in previous winters would test positive for the disease, and be needlessly killed. I was pleased to learn our vets expanded their repertoire to six different tests before any elk was sacrificed, and at least one of those was able to tell infected elk from inoculated elk

On chronic wasting disease (CWD)...

The new hot spot of the disease found last year?

Not so new. After collecting and testing 200-some deer, they found out roughly 3 percent were infected. You do the math, and that works out that the disease has been in that population for at least 10-12 years.

We just hadn't looked hard enough before.

But yeah, I've still got it immediately to the south, east, and northeast, so we'll be pulling retropharyngeal lymph nodes again this fall. (And from roadkills, like the two I pulled last month.)

Still no cases in people.

None expected, either.

Survey found out at least 50 percent of our hunters who had their deer tested for CWD started eating it before test results came back.

The popular media carried a story months back that the prion that causes this disease had been found in muscle tissue, not just nerve tissue.

Turns out that's not exactly true. What they did is feed meat from infected mice to healthy mice, and the healthy ones got sick. Ergo, it is in the meat.

Got the results of the study done with human-mice and cervid-mice...

You don't know about human-mice and cervid-mice?

A human-mouse is a mouse genetically modified to have human nerve DNA instead of the normal mouse nerve DNA. So you get mice with nerves that are chemically identical to human's, instead of a mouse's. Likewise for the cervid-mice, which have chemically identical elk nervous tissue.

I'd love to have the powerpoint slides for this. The vet with the broken arms used a mouse with his own face to represent the human-mice. And a mouse with a bull elk head for the cervid-mice.

Cute stuff.

Aaaanyway, the gist of the study?

Cervid mice get CWD, and die.

Human-mice don't.

Looks like we can keep on eating deer, elk and moose.

The afternoon started with the new hot topic... avian influenza (bird flu).

No, it's not here yet. But is expected. The question is, will we get a slow, mildly infectious disease like most waterfowl influenzas are, or will it mutate into something more virulent?

Just for the record, as of 30 April 06, there had been 205 human cases with 113 deaths from avian influenza. In the entire world, in 10 years of this disease being recognized.

Not a big problem. We lose an order of magnitude more people just in the US every year to regular flu.

But there is always that potential...

Biologically, waterfowl and shorebirds are the original source for most flu bugs. Only when it gets into mammals and mutates does it really become a problem.

And never, never does a mutated flu bug go back to cause problems for the originating waterfowl.

Except for this one.

Hence the worry.

And then there was West Nile virus. Had the region's number one expert for this presentation.

So far, Washington and Maine still have no cases. Otherwise, the other 46 continental states are infected. Crossed country from 1999 to 2004.

Most folks are aware of the pattern in WNV cases. You get lots of infections in your second year, and then they drop off dramatically.

Held true in most cases. Folks thought people and birds were becoming immune (you survive WNV, you're pretty much immune for life).

But that isn't so.

The Red Cross tests their blood donations for West Nile. Seems even in the early states, only about 5 percent of the people have been exposed.

So it has to be something else.

Looks like it's weather.

Disease is spread by mosquitoes, and in particular only a handful of the 60-some North American species that can carry WNV actually are a problem. Most mosquitoes don't feed off of both birds and mammals.

Most of these mosquitoes don't do well in cool weather. Their larvae are slow to mature, so cooler summers and early falls really limit the number of these species of mosquitoes that are flying around. They need like twelve days of average temperatures (the average between daytime high and nightime low) at 79 degrees or above to mature into flying, biting bugs.

Fewer infectious mosquitoes = fewer WNV cases.

The years when infections peaked so badly in the Mid-East (Indiana is not West, folks) and East were exceptionally hot. The next two summers were cool. Likewise for those of us in the Western NorthAm, a year later.

So, the disease experts are expecting increased problems for some parts of the country this year.

Like us.

Where we're having a hot, dry summer.

The primary carrier mosquitoes also don't do well at high elevations. Say, 8,000' and above. Which is why those of us along the Divide have been so lucky so far.

And why we have not seen the hoped for 33% decline in feral horse populations.

Oh, and as a side note. Several bird species carry high loads of the virus.

One of them is the common House Sparrow. Otherwise known as weaver-finches in their native Europe and Africa. Yeah, those little brown flitty-twits that like to hang around shopping malls and fast-food parking lots.

Just thought you should know.

From a practical standpoint, it was interesting to see how the researchers' needs varied.

The folks monitoring avian influenza specifically do not want to test birds that civilians find dead. First off, it's gotta be really fresh and properly cooled for the test to even work. But also, they don't expect it to show up first in anything ordinary folks will find. It'll probably be in ducks or geese. And there'll be a lot of 'em dead at one time.

West Nile, on the other hand, can kill any bird, and it'll probably just be one here and one there, as usual.

They want all the dead birds we can send.

Oh, and I learned how to collect samples for avian influenza. I'm one of a couple handfuls of specially trained personnel in our state, now.

You see, you stick a cotton swab up the bird's cloaca (anus), twirl it around three times, knock off any clinging feces, and seal it in a tube.

Complicated stuff. Don't try this at home.

We're what you call "experts".