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Hallo zusammen,
ich habe noch etwas information ueber demodex und die Vererbung desselben gefunden. Wen's interessiert:
In some breeds the heritability of demodecosis is pretty well established but in other breeds there is more of a question mark. When it is very important to establish heritability it is generally best not to treat the puppy until the infection is clearly generalized. Many puppies develop localized demodecosis lesions (confined to the head or a couple of areas on the body) and eventually outgrow it as their immune system strengthens. When a puppy does not outgrow the mange or when it spreads to several sites on the body it is most likely to be generalized demodex and is therefore more likely to be an inherited condition thought to occur from a deficiency of a specific type of T-cell. It is tough to make a decision to spay a good bitch or to neuter the sire, or both, when generalized demodecosis appears in a small percentage of puppies in a litter. This definitely could be, is even likely to be, genetic. The mite is present on most dogs but does not cause disease -- so the inherited component in this case is the susceptibility to hairloss and secondary skin infections as a result of overgrowth of the mite population -- NOT the infection with the mites, itself.
The breeds with a known tendency to develop demodecosis include the shar pei, West Highland white terrier, Scottish terrier, English bulldog, Boston terrier, great Dane, Weimaraner, Airedale, Malamute and Afghan. If your dog is one of these breeds, it would be wise to be even more suspicious of an inherited component to this disease.
There are systemic conditions which seem to bring on relapses or new occurrences of demodecosis. Cushing's disease is the most notable but this is present primarily in older dogs. Liver disease seems to be able to predispose dogs to demodecosis and is also more common in older dogs. Any condition causing sufficient immunosuppression can lead to problems with demodicosis so it is always a good idea to look carefully for an underlying cause, especially in a older dog suddenly showing signs of Demodex infestation.
To the best of my knowledge there is no way to prove that demodecosis is occurring due to an inherited tendency in an individual dog, or to disprove this. If the condition is not treated and resolves on its own, that is a good sign that an inherited immunodeficiency is not present but there is no way to tell that in this puppy except that it doesn't sound very plausible with the history given. If the pup had responded well to medications it would be more arguable that the condition was not likely to be genetic.
So that's the best I can do. Even though only one puppy is affected, you have to seriously consider the possiblity of a genetic disorder in the puppy. The decision on breeding or not breeding, considering the rest of the information, such as the low incidence in the two litters, is not mine to make. My sentiments lie with not taking any chances but I am like many veterinarians --- convinced that there are too many dogs in the world as it is and sure that highly selective breeding is best. Many dog breeders have an entirely different outlook on this situation, understandably.
Michael Richards, DVM
Ich hoffe, das es einigermassen vestaendlich ist.. war zu faul zum uebersetzen... :-))
Gruss ]
BINE
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