Ideally, dogs should be taken to council-designated areas where they can be safely let off the leash to run free. It is important to use these specifically designated areas not only to ensure their own safety (preventing the risk of being hit by a car) but also the safety of farm livestock and wildlife which can be threatened by a dog let loose in their habitat.
Pedigree or purebred dogs are more expensive to buy if purchased from a breeder and their nature and appearance is generally predictable (as they should conform to a breed standard). Crossbreeds (or 'designer dogs') are dogs of mixed ancestry. They are robust and often make great pets. Keep in mind though, that when you purchase a crossbred puppy it might be difficult to accurately predict how these puppies will develop. Both purebred and crossbred puppies and adult dogs are available at RSPCA Adoption Centres.
Diarrhoea is similar to vomiting in that it is a clinical sign rather than a disease itself. Diarrhoea can be a sign of a mild digestive upset or of something more serious e.g. food poisoning or ingestion of other toxic materials. Acute and chronic diarrhoea can be life threatening, particularly in puppies or older dogs. If the diarrhoea lasts longer than a couple of hours, contains blood and the dog appears to be in pain and has a fever then veterinary attention is required immediately. Treatment in this case will include identification and appropriate treatment for the underlying condition causing the diarrhoea as well as fluid and electrolyte therapy. Mild cases can be treated at home by removing food for a period of 12 hours and then re-introducing small amounts of bland food (e.g. chicken and rice). Probiotics can also be a useful addition to improve the overall health of the affected dog’s intestines.
Lungworm larvae may be present in slugs and snails, and if eaten, pets may be infected with worms that make their way to the lungs, where they block airways and make breathing difficult. Most dog wormers don't claim to treat lungworm, although some cat wormers do. Research conducted internationally has found moxidectin, which is found in some heartworm treatments for dogs, to be effective against lungworm, but this claim can't be made for dogs on packaging in Australia. Check with your vet as to whether it's an issue in your area, and discuss the best preventative treatment.