[Jacob-list] certified scrapie free

[gotothewhip at aol.com]

Scrapie is an interesting situation.  I work closely with the state on this, while my herd is not certified as we have not yet closed the doors to ewes( but we expect to soon)  Due to my position with the University and in Extension, I handle a few field questions on Scrapie's and the Scrapie's program.

Let me fill you all in on a little bit of info:

First off.. My background... I worked at a University Vet Diagnostic lab for many years, specifically running the Scrapie's testing in the Histopathology lab.  Then add in my recent experience with CWD in Elk, and I feel pretty well versed.

OK, I guess we all need to acknowledge the "disease" for what it is.. a Prion based issue.  Prions are proteins, and I could get into a great deal of chemistry here.. but lets think of this protein as something that can worm its way into a system thru amino acids.  It is a degenerative protein that causes the proteins to be disfigured and eventually kill some cells.

Keep in mind that these prion based situations are classified as Transmissible Spongiform Encephalpathy  (TSE's)   TSE's are expressed in several species, including humans.

CWD- Chronic Wasting Disease in elk & Deer (and concern in all cervids, but basically right now, North American Elk, Whitetail and Mule Deer are most effected, with Fallow deer showing strong resistance if not immunity)  Seen as early as 13 months in one of my personal animals, and rare after age 10
 
BSE- Bovine Spongiform Encephalopathy "Mad Cow Disease" , obviously effects cattle  Primarily seen in animals over 18 months old.  I am not aware if it is unusual to see in  MUCH older animals (8 yrs +) or not....I should look into this

Scrapie- Sheep disease, again seen in animals over 18 months

Humans can have Creutzfeld-Jakob disease (pronounced with a long A) and a short list of other diseases with similar symptoms.

The question of the prions ability to jump species is not fully understood at this point.  There are heavy (not proven) accusations that CWD is the result of captive cervids being forcibly exposed to scrapie positive animals and their fluids.  Again this is not documented to my knowledge, but is definitely an example of concern.  

Now lets talk about HOW THEY GET IT.... and again we hit a wall.  For example... Prion positive material can be found in most areas of animal confinement where a positive animal has been.  It is found in their manure, in water,in feeding areas, in fetal fluid, in the blood, in the hair....... can you see where this is going?  

I will speak in respect to CWD, as I said, I am most up to date with it.....

Our elk herd had been closed for nearly 10 years.  We were a single fence operation.  This is different from many newer facilities that require "double barrier" fencing.  Meaning, the require 8 ft fence may have an additional 8 ft fence on the inside, or even a hot wire fence system on the inside.. basically to avoid contact with animals outside the fence.

So we had brought NO (males  or females) into the facility in 10 years, the only additions that had come to the herd were births of animals.  Now keep in mind, that during the 10 years of no new animals coming in, under the previous owner (we had only owned the facility and animals for 9 months when we had the positive animal) there had been 2 unreported deaths.  What that means in the elk world, is that 2 animals died without tissues submitted for CWD testing.  Here in Colorado, we are required to submit at minimum a specific piece of the Obex (brain stem) to a testing lab for CWD testing.  The animals that were unreported were found too late to submit tissue on.. meaning they were rotten

We had a young cow go missing from the herd in early July last year.  We didn't panic the first 12 hrs as she was likely calving down in the Sagebrush and hid out with her calf.  At 24 hrs we went looking for her, and she was found 6 hrs later QUITE dead.  We removed her entire head and submitted it.  It came back positive.

We went into quarantine, and volunteered for a new testing practice of elk.  While not a legal test, it is a live test of lymph tissue.  We had all of our animals tested using lymph tissue for rectal biopsy.  We had 3 additional animals test positive.  A Yearling Bull, A Yearling Cow and an Aged Cow.  We opted to kill off the entire herd to meet state standards.  

We did quite a bit of testing on the facility.  CWD prion was found in the creek water that flowed into the ranch.  Prion was also found in manure, and on mineral/protein licks we provided.  Saliva samples did not show prions from any of the animals (I thought this was curious) 

Something to keep in mind... Prions are difficult to reasonably kill.  Basically we abandoned the ranch and all of the equipment on it.  We are letting it set vacant for an unknown period of time, hoping we will find some answers to future options.  The State believed that our animals came into contact with CWD from a positive animal OUTSIDE the fence.  Meaning.. that animal may have had nose to nose contact with our animals, or our animals may have drank or somehow eaten the prion.This is the typical suspect as young elk calves (like lambs) eat dirt and chew on everything.

The State was able to allow us to sell the meat off of some of the animals to individuals who were aware of the CWD status on the ranch.  The animals we were able to use for meat were those who tested negative on 3 consecutive tests
-Rectal Biopsy
-Obex
-Lymph Nodes (also collected at butcher) 

These tissues were all tested, and if all 3 came back negative, the person could own that carcass... it was an interesting process with one final hurdle.. We had a yearling heifer  (Orange 55) test NEGATIVE on Rectal Biopsy, NEGATIVE on obex (Which is considered the "Gold Standard") and then POSITIVE on lymph tissue.  That animal was donated to CSU for research, and they believe that they may have seen the earliest infection of an elk in that animal.

What we saw as owners:  The positive animals behaved diffidently.  Even Orange 55, when we drove out to the pasture to shoot her, she behaved differently than any of the others... My husband said "I bet she is positive" of which I laughed off as she had been neg on rectal.


So... I guess you all can estimate that I am pretty wary of the Scrapie status of my animals... So what do I do and what does it mean?

First off,.... I am a HUGE believer in the Necropsy process.  I want to know WHY an animal died, and what I can learn from that death.  Necropsy can be a fair cost to the owner, who has no hope of recovering that cost, but if it prevents a disease or situation in the future, it will pay for itself.  

Second:  I test my herd for the codon 136, 154 & 171.  I first did my rams, and aged ewes, and am working my way thru the flock,  here is a link to an APHIS article, while a bit dated, still correct on most accounts..  
http://www.aphis.usda.gov/animal_health/animal_diseases/scrapie/downloads/scrapie_genetics.pdf

So lets sum this up... We dont know How they get it, We dont know where they get it, and we cant really kill it.... But as sheep owners we have a tool (something the cattlemen and Elk breeders dont have) to test the susceptibility of the disease in our herd and a method of improving that.  All of my current rams are AARR, so I have a good deal of confidence in what they produce, and I have yet to see a Jacob sheep be QQ in my herd.  I would love to hear from anyone that has had a QQ Jacob....


Hopefully this wasn't too much of a ramble, as I have taken a number of phone calls (and a pleasant interruption of an ice cream break) during typing all of this out! 


Jennifer Tucker
Moose Mtn Ranch
Bennett, CO
www.MooseMtnRanch.com







-----Original Message-----
From: Betty Berlenbach <lambfarm at tds.net>
To: BIDEWEE at aol.com; jacob-list at jacobsheep.com
Sent: Tue, Jul 20, 2010 3:11 pm
Subject: Re: [Jacob-list] certified scrapie free


Thanks, Karen, that makes great sense!  

----- Original Message ----- 
From: BIDEWEE at aol.com 
To: lambfarm at tds.net ; jacob-list at jacobsheep.com 
Sent: Tuesday, July 20, 2010 1:05 PM
Subject: Re: [Jacob-list] certified scrapie free


Hi Betty,
In theory, the longest it would take for signs/symptoms of scrape to appear in live animals is 5 years.  The current theory for transmission is that scrapie is passed from mother to lambs via birth fluids.  Apparently it's also possible for other animals housed in the same area to be infected from the birth fluids.  
 
When you're enrolled In the voluntary scrapie program, a state vet comes out once a year to inspect your flock for signs of scrapie.  Enrolled flocks must provide the USDA with annual records (complete with names and contact info) of all incoming and outgoing sheep.  In addition, all farm born animals over 18 months must be tagged and added to the flock 'inventory' and cause of death must be provided for all deceased animals.  
 
To be certified in the voluntary program, a flock must go 5 years without signs/symptoms of scrapie appearing in the flock and without adding any non-certified, unknown or suspect animals.  Rams don't affect status since scrapie isn't apparently transmitted through semen.  Ewes can be added from certified flocks without affecting status, but if they're added from un-enrolled or enrolled (but not yet certified) flocks, the flock will revert back to the status of the flock the ewe came from.  Example, we enrolled in the voluntary program in 2001 then bought our Huntsberger sheep in 2003 so our status reverted back to year 1 since the Huntsberger sheep weren't on the voluntary program.  Our flock was certified in 2008 because we hadn't added any ewes from non-certified flocks in the ensuing 5 years.  
 
Obviously a live animal test would be more precise but until an affordable, effective live animal test becomes widely available, this is the system the USDA uses to consider a flock to be scrapie free.
 
Hope that makes sense,
Karen Lobb
bide a wee farm
www.bideaweefarm.com
 
 

In a message dated 7/20/2010 9:15:14 A.M. Pacific Daylight Time, jacob-list-request at jacobsheep.com writes:
If the only way you can tell if a sheep has scrapie is through examing its brain when it's dead, how can a flock be certified scrapie free?  I'm just curious as to the process.  I know that the mandatory scrapie program simply has people record who got sold to whom and keep records, in case, when randomly checking for scrapie, they come across a sheep that has it and can then, track it back.  But I'm not entirely sure how the voluntary program works in such a way that it can certify a flock scrapie-free?  All explanations welcome


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