Severe Combined Immunodeficiency Disease
What is SCID?
SCID is a deadly diseased gene affecting horses (primarily Arabians) all over the world. SCID (Severe Combined Immunodeficiency Disorder) is a recessive disease gene that is inherited, passed on to new foals from carrier parents. In order for a foal to become AFFECTED by the disease and eventually die, it must inherit TWO diseased genes, one from the Sire and one from the Dam. Simply this means that both the Sire and the Dam would have to be SCID carriers. A carrier bred to a clear, will produce a normal healthy foal with a 50% chance of being a carrier. Two carriers should never be bred.
SCID is Terminal!
No amount of love or money will save your foal if it is Affected with SCID. Usually the foal will Die within the first 3 months. Although it takes two disease genes (2 carriers) to give a foal SCID, a foal will live with one inherited diseased gene. One disease gene will make your foal a Carrier.
The SCID Carrier!
Carrier horses do not get sick from SCID and can live out a normal life, although, if bred, they can pass on a SCID disease gene. The present report describes a PCR-based test for detection of the gene defect and the results from testing 250 randomly selected Arabian horses. The frequency of SCID gene carriers was 8•4% (21/250). Based on the gene frequency reported here, the authors would expect 0•18% (1 out of 567) of Arabian foals to be affected with SCID based on a random breeding population." http://www.ncbi.nlm.nih.gov/pubmed/9682449 By breeding Carrier to Clear we can maintain the trait quality while controlling the appearance of the SCID foal, and. may produce a clear foal, preserving the pedigree without worry of passing the gene on to future generations.
The SCID Truth!
New DNA studies are being done all the time on this genetic disorder and hopefully one day there will be something that can be done to help the SCID foal, but in the meantime it is we, the owners and breeders that have the responsibility to STOP this deadly baby killer. Currently it is estimated nearly 28 % (1 out of every 4) of the adult Arabian horses are Carriers of this disease and have the potential of passing the gene or the potential to be MISTAKINGLY bred to another carrier and producing a SCID foal. DO NOT BOYCOTT the SCID CARRIER! We want to maintain the beauty and the traits that the Arabian offers and careful breeding programs can help to breed out this disorder without losing those qualities. This disease can only be passed to the unborn foals. If you breed a CLEAR Stallion/mare to a CARRIER mare/stallion, the mare/stallion CANNOT infect the stallion/mare.
How do you get a SCID Test?
Testing for the SCID gene can be done many places. Your local vet can do it for you and send your samples to a lab. You can also contact the lab yourself or through IAHA and get a test kit and do the collection yourself and submit it to the lab yourself. We will use VET GEN LABS thru ARABIAN F.O.A.L. ASSOCIATION for our tests here. The lab will run the tests and the results will be sent to you DIRECTLY to protect you from anyone knowing the results but you. What you do with the information you receive, is up to you but, announcing carriers is the ONLY way we can STOP the death of our treasured Arabian foals.
What are the costs of the Tests?
To some people the costs seem a bit high, but when you consider that:
1. SCID foal could cost thousands in treatment.
2. You might suffer emotional trauma at losing your foal to the SCID gene.
3. That your Mare or Stallion may be bred to another carrier horse and result in another SCID foal being born, causing all of the above problems for someone else
4. Having this information can help you to breed your horse responsibility and assure that NO SCID foals are born, thus protecting the quality of the Arabian Breed.
Then the cost is REALLY NOT that great. The cost thru ARABIAN F.O.A.L. ASSOCIATION is $99.00 for each horse. VET GEN LABS is charging $140.00 for one horse. Discounts are given for multiple horses tested.
2-7 horses (same owner)-$119.00 per horse.
8+ horses (same owner)-$98 per horse.
The test is offered to the public to help control and destroy this deadly disease, but it is up to US to utilize it. VET GEN LABS does offer discount to test for SCID, CA and LFS $216, They do offer multiple discounts.
How is the SCID Test Done?
You can do the test, by yourself or have a vet do it. Blood can be drawn or a cheek swab can be used to get tissue from inside the mouth. The cheek swab makes it simple for individuals to do the test for themselves. Everything that you need to do for SCID test comes in the kit that will be provided for you from the lab. You do the SIMPLE collection and then send it in the envelope provided for you.
What do the Results Mean?
The test results are quite simple to understand. A horse is either CLEAR of the diseased gene, or is a CARRIER. An AFFECTED horse (foal) of course dies. Here is a brief accounting of what these results mean.
1. CLEAR - the horse is clear of any SCID genes and cannot pass a diseased gene.
2. CARRIER - Although this horse is a carrier IF bred to a CLEAR horse it will NOT produce any SCID foals. A carrier horse does not die from the diseased gene.
When bred to a CLEAR horse these carrier animals can produce 50% CLEAR and 50% CARRIER foals. These horses however, should NEVER be bred to another Carrier horse, see Stats for more details on how horses should be bred, to ensure that NO SCID foals are born.
3. AFFECTED - these unfortunate foals are affected with the SCID and will not live past a few months of age
Will Telling People I have a SCID Carrier hurt my business?
Well, I could be like the people I see writing MOST of the articles on SCID and say, "oh no it won't hurt you at all." I personally do not think that is the case. I think there will be people who will avoid you like the plague (the ignorant ones) but hopefully like all new and scary things this will change. I know I was VERY nervous when I was waiting for the test results to come back on SWA Ansair. I had made a moral choice that if the results said he was a carrier that I would no longer breed him or at least breed by making sure my mare owners were informed that he was a CARRIER.
Unfortunately, he was Carrier. I decided to research and educate myself about SCID and chose to only breed to Clear mares. I am hoping people are getting better about this problem and are beginning to understand that WE NEED to breed CARRIER horses that have the quality that we have always tried to maintain in the Arabian but, there are always those who do not want to hear it, or learn, they only FEAR!
Why Should I Tell if I have a Carrier Horse?
1. The test is designed to locate Carrier horses NOT to discourage the breeding process. If you do NOT know you have a carrier horse you cannot prevent the birth of the SCID foal. You could be passing the gene unknowingly. My knowing you have a carrier you can make sure you only breed to clear horses.
2. Assuming you are breeding NOT only for money but to maintain the quality of the breed; it is your obligation, your job, to inform others. By setting such an example more and more people will come forward. Finding ALL the carriers is the only way this disease will be eradicated from this once vibrant healthy breed of horse. The more aware mare and stallion owners are the less likely they are to shy aware from carrier horses.
3. Knowledge will help ease the fears. By coming forward with a carrier horse you assure that only
clear horses will be bred to him.
If you Breed a CLEAR Stallion to a CARRIER mare or if you breed a CLEAR Mare to a CARRIER Stallion you will get Foals that are Clear and Carriers at a ratio of 50/50. You will NOT get any SCID Foals!!
This would be considered the an Acceptable breeding situation.
If you Breed a CARRIER Stallion to a CARRIER mare you will have a 25% chance of getting a SCID FOAL There will be 25% chance that the foals will be CLEAR and there will be a 50% chance that the foals will be CARRIERS. This is considered to be a HIGH RISK breeding situation and is not encouraged.
It is important to know that the ratios above apply to each foal born, in other words, the ratios DO NOT mean that if you , for example, breed a carrier mare to a clear stallion 8 times that you are certain to get 4 CLEAR and 4 CARRIER foals, or that if the first four foals are CLEAR then the next 4 will be CARRIERS. It means that EACH foal as an individual has a 50/50 chance of being CLEAR or CARRIER. The next foal born will have the same odds.
Who is responsible to Test for the SCID?
For the most part ANY person owning a Mare that they plan to use for breeding, breeding Stallions, or horses, they plan to sell that may be used for breeding by new owners should be tested. Many people differ in their ideas on whether the CARRIER horses should be allowed to breed or not. Some feel NOT producing SCID foals and a 50/50 chance of producing a carrier is a calculated risk they are willing to take. On the other side of the coin there are those that feel ALL carriers should be stopped from breeding to assure that this disease gets wiped out. This choice is a moral one that each person has to make for him/herself.
From a business standpoint some of our TOP Stallions and Mares may be carriers and not breeding may hinder the advancement of the breed and devastate breeders financially. Even though I advocate gelding most SCID-carrier colts, I still believe we should try to preserve our best bloodlines. I didn't know until much later that my *Corsair son, was a SCID carrier. When I found out, I tested his foals; I still had homes for them all, carriers where gelded or sold to be riding horses. Had I gotten a colt that was a carrier, but was superior, I would have kept him. Thus you can stress that your horse may produce a clear foal, preserving the pedigree without worry of passing the gene on to future generations. I would certainly risk the chance of getting a 'clear' foal to obtain such valuable bloodlines.
Another disagreement is that some people feel that ONLY the Stallions need to be tested. Well, first of all a Stallion owner may not want any carrier produced by his clear stallion or may not want to breed to carrier mares, he is entitled to know if your mare has the SCID gene. On the other side the mare owner has the same right to know about the stallion. Everyone involved in the breeding process needs to rally to this cause and help to eliminate this gene from the oldest, purest, most magnificent breed of horse to ever walk the earth.
Regardless of what your positions are on any of the above subjects, the fact remains that the SCID gene is a problem that belongs to us all. Selectively breeding CARRIERS will avoid SCID foals and eventually weed out the gene. It would be quicker to NOT breed the CARRIERS at all but I think we all can recognize the superior genetics that could be lost doing this.
The problem like AIDS in humans will not go away if we ignore it, nor will it improve. Fear and lack of education on the subject is our worst enemy. Don't just test your own horses encourage everyone you know to test theirs too. Spread the word and help others to understand the importance of combating this deadly killer of our future stars of tomorrow. Also, do not make the mistake of thinking that your perhaps small breeding facility does not matter or that the 10 foals you produce each year isn't enough to be significant, everyone no matter how BIG or SMALL needs to actively participate in the control of the SCID gene.