Sunday, January 24, 2010

Testing elk for brucellosis


Today I accompanied the Wyoming Game and Fish Department to photograph the process of testing elk for brucellosis. The testing program, in its fifth and final year, takes place at three elk feedgrounds on the western flank of the Wind River Mountains. I've covered the testing program every year for various media.

The photo above shows the elk trap - a huge wooden corral setup, at the Muddy Creek elk feedground.

Brucellosis is an incurable highly contagious disease associated with the reproductive tract, so only adult female elk are tested. All bulls and calves are released (although eartags are placed in the calves' ears for future identification if needed).

The photo above shows the chutes elk are processed in. After being moved from a large round corral, they are pushed into alleyways, and groups of about six are separated into paneled boxes, and eventually sorted into individual chutes, where they can be "squeezed" and handled.

Blood samples are drawn from a vein in the neck. If the individual elk is excessively nervous, a blindfold is used to help calm her. I liked how this elk remained rather calm, but never took her eye off the biologist working on her.

A calf is released from the chute after an eartag was inserted into its ear.

These adult females have all been processed and will be held overnight in the trap, awaiting their fate. Each blood sample has a number that corresponds to the rubber tags around the cow's necks. Animals that test positive for brucellosis will be sent to slaughter, and the remainder will be released back onto the feedground.

The test-and-removal program is a five-year effort aimed at reducing the presence of the disease brucellosis in elk herds along the western front of the Wind River Range. Brucellosis is a contagious disease that causes abortions in hoofed animals and is present in elk and bison in the Yellowstone region. Brucellosis transmitted by Muddy Creek feedground elk to a neighboring cattle herd in 2003 resulted in the slaughter of the entire cattle herd. Several other cattle herds were later destroyed for the same reason, and transmission from elk was indicated in all cases.

Brucellosis can also be transmitted to humans - right off the top of my head I can name five people I personally know who have had it (three vets and two ranchers). It's a horrible disease, and as many of you know, is subject to control efforts throughout the world. Some hospitals in Central Asia have entire wards dedicated to treating patients with this disease.

Brucellosis seroprevalence rates in elk using the Muddy Creek feedground have progressively decreased from 37 percent to seven percent in the first four years of the program.

9 comments:

Anonymous said...

Ok Cat, I'll bite! In dogs, we test both dogs and bitches and the threat of brucellosis is something we're all aware of ....

Why wouldn't wildlife agencies test bull elk as well?

Cat Urbigkit said...

For various reasons, bull elk are unlikely to pose much of a transmission risk. Brucellosis in wild elk is transmitted by abortion events, which usually occur in third trimester – in Wyoming it’s when elk are concentrated on winter feedgrounds. Behaviorally, cow elk in a herd nearly always insist on inspecting aborted fetuses, sniffing and licking the fetus and birth fluids – this is a major mode of transmission.

I was glad to hear that only four of the 82 cow elk handled yesterday tested positive for the disease.

prairie mary said...

In weird way we've come a long way. In the early part of the naughts, there were buffalo huggers who insisted there WAS no such thing as brucellosis, that it was just a government myth to excuse the murder of innocent buffs. Even when people who had been laid low with the stuff testified to what it felt like, these crusaders simply wouldn't listen. When they were three they threw a fit everytime they didn't like something and they thought it might work again, I guess. It didn't. Reality outwaits everything else.

Prairie Mary

Anonymous said...

Back again - I can see why the "sympthetic" behavior of the cows poses a larger threat to transmission of the disease, but, if you have time, would you touch on some of the reasons the bulls are not considered to be "high risk?"

My information says that brucellosis is transmitted through urine as well as physical contact and for that reason we isolate and test all dogs coming onto our property. The threat is probably also a good reason for the increase in the use of "AI" in dogs, but I'm not sure anyone would ever admit that.

Anonymous said...

Thinking of cow elk and herd behavior brings to mind one of my favorite memories. While driving toward the western entrance to the Rocky Mountain National Park, we were brought to a halt by a large number of cows with their calves ambling along the road, and then crossing the drive when traffic stopped. As the cows approached the crossing spots they would accelerate to a long ground-covering trot and the calves, of course, would run to keep pace with their mothers. The babies would stretch their heads up to the limit of neck length and rest their heads and necks on their mother's shoulders. As I watched this behavior, several babies lost their grip on mom's whithers, and the cows would stop immediately and wait for the babies to catch up and establish contact before leaving - what amazing protective instincts Mother Nature provides.

Cat Urbigkit said...

Canine brucellosis is a different species than Brucella abortus, the species found in wild elk and bison. Brucella abortus is not shed in urine - the organism is shed in birthing tissue and fluids, and vaginal discharge, so the organism is shed when an animal aborts or delivers a calf. The organism can actually hide undetected in the reproductive tract of an ungulate - that's why a negative test doesn't always mean the animal doesn't harbor the bacteria. Repeated testing is necessary.

Cat Urbigkit said...

I hope my last comment reveals more about why bulls aren't much of a threat. Since this bacteria lives in the female reproductive tract, it is shed at a specific time and manner - in the birthing process. Other animals can become infected by coming into contact with the shed bacteria through touching/nosing/licking the fetus or fluids, or through contact with an environment contaminated with discharge from infected animals (such as ingesting hay on a feed line on an elk feedground).

EmilyS said...

um no: there were no huggers who denied the existence of brucellosis in bison, or the possibiity that bison might be passing it to cattle (though it was difficult to prove that this happens in the real world). The question always was.. and still is.. why they are killing bull bison for brucellosis control since the disease is transmitted through abortion events. And why are they not killing bull elk for that reason? The answer has little to do with brucellosis itself.

Anonymous said...

Thanks Cat - that does help my understanding a great deal ... one more question ... is it not possible then for a bull elk to contract brucellosis during the actual breeding proces

Sorry to be so dense ...