As an offshoot of what happened with Major, may be we could discuss what distemper and hepatitis really are and how they can be prevented from affecting dogs.
According to what I have researched, canine distemper is caused by a virus of the paramyxovirus family and is contagious. It mostly strikes the respiratory, gastrointestinal and central nervous systems of dogs and manifests itself through a runny nose, fever, vomiting, loss of appetite, heavy breathing, seizures and poor motor coordination.
Whether a dog will be able to fight the virus depends solely on its immune status, which should be boosted by an annual vaccination routine. In Major's case, our greatest mistake was that we hadn't vaccinated him the year he died, because of which his immune system became extremely vulnerable.
Hepatitis is also caused by a virus - the canine adenovirus type-1 - and targets a dog's liver. Some of its symptoms are similar to those of distemper, such as loss of appetite, coughing, vomiting and fever. Like distemper, canine hepatitis is also contagious, and a combination of both the diseases can be fatal.
That's the reason why I can't stress enough on the importance of regular vaccinations for your pet dogs. I've learned from my error the hard way, but you don't have to. Care for your dog's health first and all good things will automatically follow.
We get our current dogs vaccinated annually against the following diseases:
2) Parvo virus
3) Canine hepatitis (Adeno virus 1)
4) Adeno virus 2
It would also be advisable to check with your vet about new strains of viruses that could affect your dog and ask for vaccinations against them.
And just for the record, what I've written in this post is based on my experiences and limited research. If you have some worthy information you would like to add, or if you'd like to correct me if at all I've said something wrong, please do so in the 'Comments' space.