Without doing an epidemiological study, I can't prove it's to do with COI. Research into Epi has only just taken off. It is proven to be genetic in GSD's However, now the condition is getting known, dogs of other breeds have been blood tested, like Marti, weeks before imminent death. I don't know whether her pedigree had a gene, or whether they were suffering from weakened immune systems. I do know that four dogs from that same breeder, a judge, died too young, from cancer, kidney probs, cushiness , and one had glaucoma. Marti was lucky that her vet found the problem, and she lived with food enzymes happily ever after.
Notably, her breeder has imported new blood lines. It is difficult for them to know if their dogs have a problem after going to new homes, if the owners don't tell them. And this applies to the people in the article as well.
Back to my dog, Did she have a weakened immune system affected by vaccinations ? Quite likely.
Environmental factors, spaniels don't always cope with kennel life, which she had for two years. But the globalt hundreds of other dogs of all breeds like her, had a variety of homes, foods, water etc.
If you have time and interest in reading the new scientific research into EPI factors , look at EPI4DOGS website, which is American, and supported by their veterinary associations . It's not a quack setup. Dr Penny Watson is associated with it, and Dr Jean Dodds.
There is a article on different breeds, and associated crossbreeds now reported with it.
Breeders need honest communication with each other, As well as common sense. I m sure you train a support dog by its aptitude. Would you train one if you knew it had the same names several times in a five year pedigree?