Dog worms are intestinal parasites which infest the digestive systems of dogs, or, in the case of the heartworm, the heart and surrounding blood vessels. Many of these parasites can also live in other animals, including humans, potentially creating a situation in which the worms will be spread and passed repeatedly. Worms are extremely common in dogs, especially in puppies, and they are typically not a cause for concern, although they should definitely be treated.
Five parasites are especially likely to be present in dogs: hookworms, roundworms, tapeworms, whipworms, and heartworms. Roundworms are especially common, and both hookworms and roundworms are zoonotic, which means that they can be passed to people along with other dogs. With the exception of heartworms, dog worms are usually not fatal, although they can cause health problems, and treatment is strongly encouraged.
Some common signs that a dog has worms include: dulled coat, hair loss, appetite loss, vomiting, diarrhea, a pot-bellied appearance, and coughing. In some cases, the worms or their eggs may be visible in the feces of the dog, or on the fur around the anus. If a dog demonstrates signs of a parasitic infestation, it is important to take the dog to a veterinarian for diagnosis, as different medications are used for different dog worms. The vet will take a stool sample and look at it under the microscope to determine which worms are present.
Dog worms are also preventable with the use of regular dewormers. Many vets recommend a basic dewormer for regular administration to prevent heartworms, which can be fatal, and many dewormers include a cocktail of drugs which also deters other worms. Dewormers should never be mixed, and it is a good idea to consult a veterinarian about any deworming product to make sure that it is appropriate for your dog. Along with regular deworming, it is also a good idea to treat dogs with flea medication, as fleas can carry tapeworm.
There are some cases in which dog worms can be very dangerous. Puppies are vulnerable to dehydration and blood loss from hookworms, parasites which latch onto the walls of the intestine and feed on blood, and all dogs are at risk of death from heartworms. Left untreated, a regular infection with dog worms can also cause a dog to be generally unhealthy, although he or she is not at risk of death. While a dog is in treatment for worms, it is a good idea to keep other animal and human residents of the household away, and to wash hands thoroughly after interacting with the dog to prevent the spread of worms.