Oh My! Looks like the club country walks are due to start.
Worms and your Dog
Broadly speaking there are two types of worms that cause problems in the dog (Roundworm) and (Tapeworm) other species are also occasionally encountered as per diagram.
In adult dogs intestinal worms, both roundworms and tapeworms, are usually not life threatening, except in seriously debilitated dogs or those that are immunocompromised.
No intermediate host is required?
Roundworms are free living in the bowel. In puppies they can present problems if not controlled. In large numbers they can stunt growth, cause serious digestive upsets and result in a lot of gas formation. The results in a typical "pot bellied" appearance.
Roundworms can be spread directly from dog to dog via infective eggs, if not not kept unchecked.
An intermediate host is required?
The common Tapeworm causes few problems in the adult host but in the growing puppy can result in digestive upsets and stunting.
The Tapeworm is spread by the Flea as intermediate host and effective treatment also must cover environmental flea eradication.
Treatment against Worms
There are many effective drugs available to control worms in the dog. Many of these are available "over the counter" without prescription. Effective worm control in the dog however involves the choice of an appropriate preparation which has to be regularly repeated. This advice can be obtained by any local Veterinary Surgery they would be pleased to help.