This highly contagious canine illness attacks puppies aged between 12 weeks and 3 years. Transmitted through bodily secretions and unvaccinated dogs, canine parvovirus is easily passed on, though most dogs should be vaccinated against it starting at six to eight weeks, then again every three weeks until they are four months old.

If a puppy is suffering from either of these nasties, the first thing to rule out is intestinal parasites. If these are not the causes of vomiting or diarrhea, the pooch has probably just eaten or licked something he shouldn’t have. Other causes could be one of the diseases listed above.

The vaccination against the canine distemper virus is quite effective. The first vaccination takes place at six to eight weeks and again after nine weeks, "and when puppies have had one or two vaccines, they are immune."

Bacterial infection or canine para-influenza viruses, both of which are airborne, cause kennel cough in dogs, also known as infectious trachea bronchitis. Puppies can be vaccinated against kennel cough starting at six to eight weeks and then every six to 12 months after that, though the vaccine doesn’t necessarily protect against the disease but does lead to milder symptoms.

Adenovirus in dogs causes infectious canine hepatitis; it’s rarely seen these days because of the efficacy of vaccines. Often, the adenovirus vaccine is given with the canine distemper vaccine.

This bacterial disease can affect the kidneys and the liver and is transmitted through contaminated water and infected urine. A puppy can be vaccinated against leptospirosis at 10 to 12 weeks, then again at 13 to 15 weeks.