Preventable diseases are illnesses that a vaccination or medication can protect against, such as parvovirus, canine distemper, and rabies in dogs.
Under the current policy wording, these are covered only if your pet's vaccinations are up to date. If your pet was not properly vaccinated and then catches one of these diseases, a claim that results from it would not be paid.
So the honest answer is: keep your pet's vaccinations current, and these conditions can be considered. Let your vaccinations lapse, and they are excluded. If you are not sure whether your pet's records are up to date, check with your vet, and always keep your vaccination card updated in your Oyen account.