Puppies should be wormed once every 2 weeks until they are 3 months of age, then they should wait until 6 months of age for their next treatment, according to VetWest animal hospitals. After 6 months of age, dogs should be wormed approximately once every 3 or 4 months.
Puppies and adult dogs can contract many different kinds of worms such as tapeworms, roundworms, whipworms and hookworms in addition to other parasites. These worms can then be given to other puppies or to human companions through simple transmission such as petting, grooming or playing. Worms can cause vomiting, diarrhea and coughing symptoms as well as shortness of breath.