Yes wolves can catch some illnesses like rabies
AIDS
No, you cannot catch illnesses from cats and cats cannot catch our illnesses. They have a different immune system than we do. There are some illnesses that do cross the species barrier. They are called zoonoses. See Related links.
Generally no. There are a few types of illnesses shared between people and animals but a stomach virus isn't one of them. Pets have a natural body temperature of 101.5 so viruses and bacteria that thrive in our bodies can not do so in theirs and vis-versa. They have their own illnesses as we have ours. We can't give them a stomach flu or catch theirs.
a cold
I don't think so but pets can catch colds from humans.
Cancer is 1 illness pets can detect, as far as scientists know, only dogs can detect it.
Yes, veterinarians prevent animal illnesses mostly through vaccinations and encouraging a healthy lifestyle for the pets.
yes
Yes
Yes. They can still catch diseases and/or illnesses.
No you can't catch fish. SORRY