Internal Dog Parasites
Types of Dog Worms

Giardia: This parasite causes a number of visible symptoms including enteritis and diarrhea; unfortunately puppies are especially affected.
There is a human form of this parasite and the resulting symptoms are the same. Whether the canine and human varieties of the Giardia parasite are the same of if it is communicable between dogs and humans is not established. If your dog presents these symptoms you should take it to the veterinarian so the correct medication can be administered.

Heartworms: As they are mosquito borne the Heartworm parasite is particularly dangerous. These parasites can grow into foot long worms that lodge themselves in the right ventricle of the heart. Once they have attached themselves to your dog's heart they cause a lot of damage to the heart as well as the lungs. If left untreated a heartworm infestation will be deadly.
Your dog's veterinarian can prescribe a heartworm parasite preventative that will help give your canine protection against these deadly parasites and at the same time should offer protection against roundworms, hookworms and whipworms.

Hookworms: The Hookworm is a small blood sucking parasite that attaches to the walls of your dog's small intestines.
Some of the common symptoms of hookworms are diarrhea and anemia.
Hookworms should be dealt with promptly and the standard prescription calls for a deworming medicine.
Roundworms: Puppies under the age of three months are the ones most affected by these intestinal parasites. Older dogs often develop an immunity that stops the parasite eggs from hatching, however if these eggs are not taken care of, they can affect the puppies of that dog because the eggs can remain dormant in the adult dog's body. When your puppy gets its scheduled deworming the medication should destroy any dormant eggs, and standard heartworm medications will stop any early infections. Roundworms are transmittable to humans.

Tapeworms: Tapeworm eggs are usually transmitted by fleas, uncooked animal meat and fecal matter. There are several varieties of this parasite and most of them fortunately cause their canine host no lasting damage.
Still all parasites should all be eliminated by deworming with medication from your dog's veterinarian and any other treatments the veterinarian recommends. There are a few varieties of tapeworms that produce eggs which can then be transferred to humans. In a human host these parasites can cause life threatening cysts.

Whipworms: The Whipworm larva penetrates the small intestine. From where they move to the large intestine, remaining there until they mature into adults. Some of the symptoms of whipworms are diarrhea, weight loss, and bloody stools. These parasites should be eliminated immediately and this is accomplished with deworming medication.