Tuesday, June 11, 2013

CAE is a real disease!

I am always shocked when I hear people talk about how Caprine Arthritic Encephalitis (CAE) isn't a big deal. Even though they have never tested, they claim that their goats "look healthy" and have never had a problem and that they must be "CAE-free". I'm sorry, but as soon as I hear "CAE-free" I tend to shudder with horror. I really don't believe there is such a thing. Your goats are either CAE negative or they are positive. They can never be truly "free" of it. If you have never tested your herd or you don't do CAE prevention, then you have no right to claim that your herd is "CAE-free".

One of the current estimates on prevalence of CAE infection in the goat world is that up to 80% of goats carry and transmit the virus to others. I have argued with people before about how they don't believe this number because they feel it is too high. They insist that since they test or use prevention and since they know others who do too, that the general population is also aware of the disease and takes action against it. I don't believe that at all. Just talk to any random goat owner and about half of them will go "Huh?" when you mention CAE. They don't know what it is and have never heard of it. You can bet hard cash that their goats are positive. The other half of goat owners will give you the "my goats look healthy so they don't have CAE" line when you question them about it. You can also bet hard cash that all their animals are positive. Don't even bother asking a meat goat breeder about CAE. I have yet to find anyone with Boers or Kikos who regularly tests. Yep, get your wallet out again -- all of their goats are positive too. So if you add the uninformed, the noobs, and the meat goat producers into the equation, you are probably approaching the 80% mark pretty quickly. 

CAE is a highly subclinical disease which means that only 10% of the animals who carry and transmit the virus will actually show the "classical" symptoms -- ie: swollen knees, hard udders at freshening, or encephalitis. Unfortunately these symptoms often get confused with other common goat ailments so the actual percentage of goats who express direct CAE-related problems may be much higher than 10%. Hard udders at freshening often go undocumented in the meat breeds or get confused with other udder related maladies in the dairy breeds. The same is true for encephalitis. There are several goat diseases that cause sudden paralysis and death, so usually when presented with those symptoms, CAE is at the bottom of the diagnostic list.

Do keep in mind that CAE doesn't only cause those classic symptoms. CAE is an immunodeficient virus that suppresses the goat's immune system and leaves them open to serious complications due to other infections and deficiencies. CAE is often called "Goat AIDS" for good reason. Rarely to people with HIV/AIDS actually die directly from that virus. It's the other diseases, like TB, that ultimately kill a person with the HIV virus because their immune system was compromised by HIV before they got TB. A normal, healthy adult can fight off a TB infection, but someone with HIV is at a huge disadvantage. The same is true for a goat with CAE. Most goats that are CAE negative will be healthier in general than their immunocompromised CAE positive counterparts.

One of the big problems with people and understanding CAE is that the current test for CAE only looks for the antibodies to the virus. This is not a fool-proof test by any means because many times a goat can carry the CAE virus and transmit it but she may not carry the antibodies to it. She may test negative but actually be infected with the virus. Some goats do not produce antibodies normally due to a preexisting immune system dysfunction and some goats have delayed antibody production for one reason or the other. There can also be false positives if the goat was exposed to the antibodies. They can carry the antibodies but not the virus, so technically they are not infected but they will test positive. Do keep in mind though, that false negatives and false positives are extremely rare!  Unfortunately this kind of confusion about the accuracy of the testing causes people to proclaim that the test is completely invalid and a waste of time. They will swear up and down that since the test isn't fool-proof that it must be totally wrong, thus they stopped testing and worrying about CAE.

Another big problem that people have with CAE is that prevention and testing is a huge pain in the ass. If you never test and you assume that your goats are healthy, then you never have to work very hard to claim they are "CAE free". You can just sit in the dark and let your infected goats spread the virus all around to their kids and their kids' kids, and sell those kids to people who also don't have a clue, and everything is just peachy. You can skip the annual testing, you can skip the bottle feeding of pasteurized milk, and you can skip having to change your herd management to eradicate the virus. Being ignorant is so much easier than being informed!

So what is the goat owner to do? TEST, TEST, TEST! It's cheap and it's easy -- about $4 per goat through the mail. Just take a blood sample (which is super easy to do -- no veterinary needed!), and pop it in the mail with payment. Then in about 5 days you will get an email with the test results. If your goats are positive then the hard work begins. You will have to evaluate your herd management and make changes so any new goats you produce are negative. Some goats can live a long time with the infection and continue to produce kids so it isn't necessary to eradicate your positive animals. BUT it is necessary that you take the appropriate steps to be responsible and not spread the virus to new goats.

If all goat owners work together to test their goats and then manage them properly, it is possible to bring that 80% number down to 50% or 20% or even 0%!

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