Hello all and thank you for being here. It's so nice to have someone to share experiences with.
Has anyone ever used PCR testing to test for CAE in their herd? I know the norm is to do the ELISA test.
Does anyone not test at all, and take Molly's approach.....just keep your goats healthy???
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I'm not sure that the PCR will always pick it up faster or sooner than the ELISA. However, you make some good points. The safest thing to do would be to do both tests. If they're negative on both, that's a really good indication that they're truly negative. Since the virus is most commonly spread through milk and blood, a goat is usually only going to give the disease to a kid that is nursing on them, so if you test all does before they kid the first time, you should theoretically catch the disease before it has spread to a second goat. Johnes is the disease that can wipe out your herd because it is spread through fecal-oral transmission, so wherever a goat poops is contaminated.
Thanks for that info. Would you say then that a PCR positive is definitive even though a goat would test negative using ELISA? Or would you keep testing with ELISA?
It just seems to me that if we all use ELISA, it's kind of too late....once seroconversion takes place the animal has probably been shedding virus all over the place. With ELISA do we really know the herd status?
PCR costs about 5X as much as ELISA, which is probably why most people don't use it. It is usually used when someone gets a suspect or positive result from ELISA to follow-up. About 1% of goats without CAE will test positive with ELISA, so using PCR after that can be reassuring -- assuming that you get a negative PCR. If you get positive on both of them, then the goat definitely has CAE.
Unfortunately just keeping your goats healthy won't keep them from getting CAE. As Patty said, you need to be diligent about buying from a tested herd, testing to be sure your animals are indeed negative, and then keeping a closed herd. Goats can only get CAE from another goat that has CAE.
We tested for a few years, but then we stopped buying goats and stopped showing goats, so we quit testing regularly. However, I discovered a benefit of testing when I got an email from someone who bought a kid from me that tested "suspect-positive" at age 2. I was able to pull out her dam's and her full sister's tests and send them to the owner and show her that both mom and sister were negative, so either her goat was one of the 1% that was incorrectly testing positive or her goat picked it up somewhere else. I suggested that she do the PCR for a definite answer. After seeing your post, I just realized I haven't heard back from her, so I don't know what happened in her situation.
You're welcome. :)
Laurie Luce said:
Thank you for that info, Patty.
I haven't tested at all, though I did buy from a tested herd in the beginning, and have kept a closed herd as much as possible. No swapping around, buying or allowing myself to be given unwanted goats from others. I am friends with the woman I got my original goats from, and I see her stock on occasion. I know how careful she is, and that she is diligent about her testing.
This is what Bio-Tracking says about the CAE tests, "The ELISA test is an indirect test and is best for active infections since it detects the presence of antibodies against the active virus, but has limitations if the virus is dormant. The PCR-based test is a direct test in that it detects the presence of the viral genome in both active and dormant infections."
I found that info HERE If you go to the link you can read a little more about it. Best wishes with your herd! :)