Equine severe combined immunodeficiency
Severe Combined Immunodeficiency (SCID) is a disease with a genetic background in Arabian horses and crossbreeds with Arabians. The disease has been known and documented since the 1970's and was early suggested to have an autosomal recessive mode of inheritance. Foals that are affected with SCID...
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| Formato: | L3 |
| Lenguaje: | Inglés sueco |
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SLU/Dept. of Animal Breeding and Genetics (until 231231)
2007
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| Materias: |
| _version_ | 1855571815886225408 |
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| author | Lund, Louise |
| author_browse | Lund, Louise |
| author_facet | Lund, Louise |
| author_sort | Lund, Louise |
| collection | Epsilon Archive for Student Projects |
| description | Severe Combined Immunodeficiency (SCID) is a disease with a genetic background in Arabian horses and crossbreeds with Arabians. The disease has been known and documented since the 1970's and was early suggested to have an autosomal recessive mode of inheritance.
Foals that are affected with SCID lack production of both B and T lymphocytes and consequently die from secondary diseases within a short period of time. The most common cause of death is infections in the respiratory tract caused by adenovirus. Maintaining foals affected with SCID has been proven difficult, but their lives can be prolonged with injections of hyperimmune plasma. A successful bone marrow transplant has also been performed.
A DNA-test for detection of carriers of the defective allele was developed during the 1990's. The test made it possible to detect whether a horse was a carrier or a non-carrier of SCID, without the use of test mating. Previous estimations of the frequency of the defective allele were based on clinical diagnosis on foals suspected to be affected with SCID. These studies were later found to have overestimated the frequency of carriers.
The frequency of SCID carriers in Sweden is low and carriers are not allowed in breeding. The present legislation is however not acted upon since horses are only tested for SCID if suspected to be carriers. The question whether heterozygotes should be allowed in breeding or not should be decided while considering the population size and the frequency of carriers. The total population of Arabian horses in Sweden is large enough to exclude carriers from breeding. |
| format | L3 |
| id | RepoSLU11146 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2007 |
| publishDateSort | 2007 |
| publisher | SLU/Dept. of Animal Breeding and Genetics (until 231231) |
| publisherStr | SLU/Dept. of Animal Breeding and Genetics (until 231231) |
| record_format | eprints |
| spelling | RepoSLU111462017-09-28T06:26:43Z Equine severe combined immunodeficiency Lund, Louise Severe Combined Immunodeficiency SCID Arabian horses genetic disease equine Severe Combined Immunodeficiency (SCID) is a disease with a genetic background in Arabian horses and crossbreeds with Arabians. The disease has been known and documented since the 1970's and was early suggested to have an autosomal recessive mode of inheritance. Foals that are affected with SCID lack production of both B and T lymphocytes and consequently die from secondary diseases within a short period of time. The most common cause of death is infections in the respiratory tract caused by adenovirus. Maintaining foals affected with SCID has been proven difficult, but their lives can be prolonged with injections of hyperimmune plasma. A successful bone marrow transplant has also been performed. A DNA-test for detection of carriers of the defective allele was developed during the 1990's. The test made it possible to detect whether a horse was a carrier or a non-carrier of SCID, without the use of test mating. Previous estimations of the frequency of the defective allele were based on clinical diagnosis on foals suspected to be affected with SCID. These studies were later found to have overestimated the frequency of carriers. The frequency of SCID carriers in Sweden is low and carriers are not allowed in breeding. The present legislation is however not acted upon since horses are only tested for SCID if suspected to be carriers. The question whether heterozygotes should be allowed in breeding or not should be decided while considering the population size and the frequency of carriers. The total population of Arabian horses in Sweden is large enough to exclude carriers from breeding. Severe Combined Immunodeficiency (SCID) är en immunbristsjukdom med genetisk bakgrund som förekommer hos Arabiska fullblod och korsningar med dessa. Sjukdomen har varit känd och dokumenterad sedan 1970-talet och tidigt föreslagen som en autosomal recessiv sjukdom. Föl som är drabbade av sjukdomen producerar varken B eller T lymfocyter och dör efter en kort tid i följdsjukdomar som uppstått p.g.a. bristande immunförsvar. Den vanligaste dödsorsaken är lunginflammation orsakat av adenovirus. Det är svårt att hålla föl som är drabbade av SCID vid liv. Man har dock lyckats förlänga deras liv genom att ge injektioner av plasma innehållande antikroppar. Även en benmärgstransplantation har utförts där fölet överlevde. Under 1990-talet utvecklades ett gentest för kontroll av bärare av sjukdomen vilket har gjort det möjligt att bestämma om en häst är bärare av genen utan att använda sig av testparningar. De uppskattningar av frekvensen heterozygoter som utfördes innan testet utvecklades var baserade på kliniska undersökningar av de föl som misstänktes vara drabbade av sjukdomen. Dessa uppskattningar visade sig senare ha överskattat frekvensen anlagsbärare. I Sverige är frekvensen bärare av SCID låg och avel på dessa är förbjuden. Förbudet följs dock inte upp i praktiken då hästar endast testas för SCID då de misstänks vara bärare. Om heterozygoter bör få ingå i avel borde avgöras av populationens storlek och av frekvensen anlagsbärare. Den totala populationen Arabiska fullblod i Sverige är så stor att bärare bör uteslutas från avel. SLU/Dept. of Animal Breeding and Genetics (until 231231) 2007 L3 eng swe https://stud.epsilon.slu.se/11146/ |
| spellingShingle | Severe Combined Immunodeficiency SCID Arabian horses genetic disease equine Lund, Louise Equine severe combined immunodeficiency |
| title | Equine severe combined immunodeficiency |
| title_full | Equine severe combined immunodeficiency |
| title_fullStr | Equine severe combined immunodeficiency |
| title_full_unstemmed | Equine severe combined immunodeficiency |
| title_short | Equine severe combined immunodeficiency |
| title_sort | equine severe combined immunodeficiency |
| topic | Severe Combined Immunodeficiency SCID Arabian horses genetic disease equine |