Don't allow your dogs to ingest raw meats or hunt rodents thus eliminating the opportunity for infection. Heartworms are transmitted by mosquitos. When a mosquito bites an infected dog, it not only sucks up blood but baby heartworms in the blood. This gets passed along to the next dog the infected mosquito bites. An infected dog may show signs of a chronic cough, laboured breathing, listlessness, and is easily tired during exercise.
Roundworms live in the dogs intestines and live by sucking blood.
Puppies often are infected through the placenta of the mother. This is why de-worming is usually begun at 2 weeks into the life of the puppy. Pets infected with roundworms usually have bloated bellies and rough looking coats. Your pet may show signs of vomiting, diarrhea, and colic. If left untreated a severe infection could damage the brain, liver, or lungs.