Other than the rabies vaccine, which is required by the state of Pennsylvania to be given every three years (after the initial puppy shots) veterinary colleges and veterinary societies have set up a recommended schedule for other shots.

The Colorado State University Small Animal Vaccination Protocol as endorsed by Dr. Jamie Bush is the standard three-shot series for puppies (parvovirus, adenovirus2, parainfluenza, distemper), to include rabies after 16 weeks of age for dogs.

Following the initial puppy immunization series, dogs will receive a booster shot one year later and then every three years thereafter for all the above diseases. The vaccination guidelines for the American Animal Hospital Association are similar.

Canine distemper --This is the greatest single disease threat to the world's dog population. Young dogs and puppies are most susceptible. Among infected puppies, the death rate can be up to 80 percent. If the infected dog doesn't die, his nervous system may be irreparably damaged.

This is transmitted through respiratory secretions.

Canine parvovirus -- This highly contagious viral disease emerged in 1978, according to the American Veterinary Medical Association. It causes severe diarrhea and vomiting and can rapidly lead to dehydration. Puppies suffer the most, with shock-like deaths. It is transmitted through fecal waste of infected dogs, and the virus is capable of existing in the environment for several months.

Parainfluenza -- This is a respiratory ailment transmitted by contact with nasal secretions of infected dogs, which is one of three major diseases that leads to what's called "kennel cough."

Adenovirus 2 -- This highly contagious virus causes a respiratory illness that also can lead to "kennel cough." The cough can lead to pneumonia if not treated.

The following diseases are among non-core or discretionary vaccines that are given to high-risk dogs based on lifestyle, particularly if they're boarded frequently or have a lot of contact with other dogs on walks.

Bordetella -- Also a respiratory infection that leads to "kennel cough."

Leptospirosis -- This is a bacterial illness transmitted through infected urine that impairs kidney function and may result in kidney failure. Symptoms include vomiting, impaired vision and convulsions.

For more information, go to the American Animal Hospital Association Web site at www.aahanet.org, which has on its home page its 2006 updated vaccine guidelines.