Dogs and cats are susceptible to several types of worms:
uppies and kittens can be infected with roundworms before they are born or soon after through their mothers milk. Because of the short life-cycle of the worms they need to be treated every 2 weeks from 2 weeks until 12 weeks.
As they get older dogs and cats are susceptible to all of the types of intestinal worms listed above so we usually commence an all-wormer from 12 weeks. They should be given this treatment: every month until 6 months old, then every 3 months for life.
Often people will align the treatment with a change in seasons to help them remember to give treatment. Some worms can be transmitted to people so it is important to maintain regular worming treatment, especially if there are children who play with pets.
Interestingly the life-cycle of fleas and tapeworms (Dipylidium caninum) are linked.
Fleas carry the immature stage of a tapeworm and can pass this on. So if your pet has tapeworms you need to treat it for fleas as well as worms!