OPP Eradication Protocol

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Judy Lewman
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Re: OPP Eradication Protocol

Postby Judy Lewman » Thu Jan 28, 2016 12:13 pm

Greetings All

Mike is correct in that a single negative OPP test, regardless of the serology used, is no guarantee that the animal is truly free of the virus and won’t test positive at a later date. Nor does it guarantee that said test-negative animal is incapable of infecting other animals in the flock (more on this later).

Mike is also correct in that a lot of good work has come out of the USMARC over the past few years. The OPP Society has been in collaboration with those researchers since March of 2012 and I second Mike’s suggestion to call, even if just to let the folks at MARC know that their efforts on our behalf are appreciated.

For anyone new to the TMEM154 genetic susceptibility research, here’s a link to the initial lay language piece from MARC that was prepared by Drs Mike Heaton and Kreg Leymaster at our request: http://www.oppsociety.org/Library_files ... proved.pdf

For the latest follow up from MARC, this link takes you to a full text version of the 2015 paper by Clawson, et al: http://veterinaryresearch.biomedcentral ... 015-0162-7 The gist of this technical paper is that variants of the OPP virus have been discovered that have adapted to infect sheep regardless of their TMEM154 genetics.

For anyone who may have missed it in ‘The Shepherd’ magazine, PM me for a PDF of a related article written for the OPP Society by Dr Mark, and reviewed by Drs Clawson, Heaton and Leymaster. This was included in our August 2015 Update, which is not yet uploaded to OPPsociety.org (my fault, soon to be fixed). This update also includes all of the TMEM154 genetic data that we've been able to capture to date for many different breeds in the U.S., including TMEM154 haplotype distribution frequencies from many private flocks as well as those at the USMARC.

In a nutshell: While fascinating, the genetic studies are extremely complex and science hasn’t come up with all the answers yet. If this was easy work, HIV (another lentivirus) would have been history decades ago. That said, the transmission findings first noted by Lynn Herrmann-Hoesing, and later confirmed at MARC by Kreg Leymaster, have been a game changer for those wanting to eradicate OPP. Elimination of the OPP virus no longer needs to be a years long slog . . . we’re proving it in Minnesota.

Respectfully,

Judy, for the OPP Society
Judy Lewman
Production Border Leicesters with Style and Substance
Minnesota http://springcreekleicesters.com

Judy Lewman
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Re: OPP Eradication Protocol

Postby Judy Lewman » Thu Jan 28, 2016 9:17 pm

Further addressing Blustery Knoll Farm’s current situation:

From your posts it sounds as though the ewe flock has recently been tested for the first time, that you want to eradicate as quickly as possible, don’t wish to retain test-positive ewes once the February 2016 lambs are weaned, and that you’re willing to do whatever it takes, including orphaning, to reach that goal. Therefore, some points to consider . . .

At the very minimum, it takes a good two weeks following infection for the animal to build sufficient antibodies to register on Elitest. So until your test-neg ewes have passed at least two consecutive Elitest rounds at 3- to 6-month intervals, with NONE testing positive on either round, don’t rely on all of them to remain negative.

Since you’ve already separated the ewes into pos and neg groups and may wish to continue with that, just remember that those with only one negative test may still be infected and therefore likely to infect their pen mates, both adults and lambs. Also, the 10’ minimum separation reduces but does not completely eliminate transmission risk.

If you decide to carry through with the plan to remove lambs for orphaning, there’s a slight chance that some lambs could be infected before birth. Rare, but it happens. And do not allow the orphan raised replacements to commingle with older ewes, on pasture or otherwise, until each group has passed the two consecutive negative test benchmark.

Because of all this, relying on typical test and segregate and grafting lambs onto “negative” ewes can be an exercise in futility. This is why the eradication strategy we’re trialing concentrates on testing of young replacements while treating the entire ‘Parent Flock’ as infected, regardless of their individual test status.

Once sufficient replacements have been attained using the above strategy, you may be able to go back and salvage some of the original ewes, again using the goal of two consecutive all negative Elitest results for each management group before mixing older ewes with the young test-neg replacements.

Definitely test those ewe lambs born in May and let us know how it goes. You may be pleasantly surprised. One flock we’ve been working with has lambed in both February and May, with the winter lamb crop testing >10% positive and those in May remaining 100% test-negative.

Good luck with all!
Judy Lewman
Production Border Leicesters with Style and Substance
Minnesota http://springcreekleicesters.com

BlusteryKnollFarm
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Re: OPP Eradication Protocol

Postby BlusteryKnollFarm » Thu Jan 28, 2016 11:22 pm

Yes, Judy. This was the first time testing. I am waiting for results on Johnes testing of the adult group before testing the May born lambs. If I have no positive Johnes tests, I will have no reason to incur that extra expense on the May lambs. If I have any Johnes infection, that will really throw a wrench in the works though. I will definitely share the results when I get them.

As I learn more I am less inclined to orphan these lambs and more interested in the approach you have outlined.

skyviewfarm
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Re: OPP Eradication Protocol

Postby skyviewfarm » Thu Feb 11, 2016 8:27 pm

Speaking to the issue of OPP, several years ago, I had the great opportunity to visit with Judy Lewman and her husband in the middle of winter. Judy graciously showed me her flock and introduced me to the subject of OPP. I realized that I had OPP in my flock. (purchased from a vet-owned flock in Iowa)

I dispersed my flock of Dorpers two years ago. I hate to say it, but I think Judy infected me with a different disease, as I'm considering getting a start in BL now. Worse, I'm not sure how to avoid buying positive sheep, unless I make that long trek to MN.

BlusteryKnollFarm
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Re: OPP Eradication Protocol

Postby BlusteryKnollFarm » Fri Feb 12, 2016 5:09 pm

Just an update. I just got test results back from my 8 spring born replacements. One positive and 7 negative. Only 3 have test negative dam's.

DonDrewry
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Re: OPP Eradication Protocol

Postby DonDrewry » Fri Feb 12, 2016 5:45 pm

skyviewfarm wrote:Speaking to the issue of OPP, several years ago, I had the great opportunity to visit with Judy Lewman and her husband in the middle of winter. Judy graciously showed me her flock and introduced me to the subject of OPP. I realized that I had OPP in my flock. (purchased from a vet-owned flock in Iowa)

I dispersed my flock of Dorpers two years ago. I hate to say it, but I think Judy infected me with a different disease, as I'm considering getting a start in BL now. Worse, I'm not sure how to avoid buying positive sheep, unless I make that long trek to MN.


When we had an OPP negative flock, I bought a ram that was negative before I bought him but tested positive after we got him. He lived in his own pen for 3 years. He only came out to breed ewes on pastures for 2 cycles a year. We didn't get any infections from that as I tested the entire flock each year I owned him.
Don Drewry

Judy Lewman
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Re: OPP Eradication Protocol

Postby Judy Lewman » Sat Feb 13, 2016 7:46 am

BlusteryKnollFarm wrote:Just an update. I just got test results back from my 8 spring born replacements. One positive and 7 negative. Only 3 have test negative dam's.

That's great news, Paul! Those 7 Elitest-negative lambs are the beginning of your OPP negative flock. The 4 neg lambs from pos ewes is not at all surprising now that we've finally learned more about how the virus spreads, i.e. primarily from respiratory secretions rather than colostrum/milk from an infected dam.

This reminds me of our experience very early on in the eradication process (late '80s). I struggled to comprehend how two who had purchased seedstock from us reported all test-negative results, leaving me with a heavily infected flock. Of course they'd purchased young lambs just a few months past weaning. Duhhhh . . .

You're on the right track. Good luck with lambing and please continue to update.

Judy
Judy Lewman
Production Border Leicesters with Style and Substance
Minnesota http://springcreekleicesters.com

BlusteryKnollFarm
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Re: OPP Eradication Protocol

Postby BlusteryKnollFarm » Fri Sep 09, 2016 6:44 am

Just an update. We just tested the flock again. Two of the yearlings that were negative at the last test came up positive now. As did 3 of the 15 ewe lambs that were born this past February. Due to barn space limitations, I was not able to maintain a full 10' space between pens during the winter. They have been isolated by 200' or more since going to grass in late April. This year, I can keep them in separate barns on different farms and the positive group goes to market as soon as they wean the October lambs.

I ran my oldest ram that I am otherwise done with with the group of test positive ewes over the summer to get October lambs, and he is now positive.

I plan to sort off the positive yearlings and ewe lambs and put them with the positive group of ewes at the other farm ASAP. How soon should I re test after isolating the positive animals?

Judy Lewman
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Re: OPP Eradication Protocol

Postby Judy Lewman » Fri Sep 09, 2016 8:11 am

That’s great news, Paul. Thanks much for the update.

Since you’re using the ‘Elitest’ ELISA at Minnesota’s VDL, I’d recommend that you retest those negatives 2-3 months following removal of the remaining positives. And I’d continue testing at 2-3 month intervals until receiving two consecutive all-negative results.

Keep up the good work!

Judy, for the OPP Society
Judy Lewman
Production Border Leicesters with Style and Substance
Minnesota http://springcreekleicesters.com

BlusteryKnollFarm
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Re: OPP Eradication Protocol

Postby BlusteryKnollFarm » Sat Apr 08, 2017 10:51 pm

I am moving my comments from the general management forum to the archive here.

Just another update. Ran another test a couple weeks ago and had zero positive test results. I only have 9 positive ewes in the quarantined flock on a separate pasture, which lambed in October. As soon as lambs are weaned, they will be going to market. It looks like the end is in sight.

This was November 2016.

BlusteryKnollFarm
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Re: OPP Eradication Protocol

Postby BlusteryKnollFarm » Sat Apr 08, 2017 10:52 pm

Just another update. We just got results back from serum samples that were collected last week. All 29 sheep and 7 goats tested negative for OPP and CAE respectively. This is the same result we had in early November when we tested previously. Four of the ewes are the original ewes that were part of the infected flock.

Additionally, 4 ewe lambs born to OPP infected dams in October and November tested negative as well. They are isolated from the rest of the flock, and we plan to keep them this way for a couple more months before testing them again.

So, here we are in a little more than a year!


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