Intestinal Parasites

Intestinal parasites
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95% of puppies are born with intestinal worms! These parasites can cause vomiting, diarrhea, weight loss, stunted growth and even death. Some kinds are also transmissible to humans. This is especially important with regards to children who may be out barefoot in the yard, or toddlers who may put soiled fingers in their mouths. Over 10,000 cases of animal roundworms cause illness in children every year in the United States.


Internal parasites are diagnosed by having a fresh stool sample examined under a microscope by one of our Certified Veterinary Technicians here at the veterinary hospital. This should be done as part of a health exam when you obtain a new puppy or dog, and on a yearly basis as part of your dog’s annual health exam and vaccinations.


Stool samples should be collected when they are fresh and stored in the refrigerator until they can be brought to the hospital. DO NOT freeze them. A teaspoon or two of stool is all that is necessary.


So that you may better understand the problems internal parasites can cause and what signs to look for, we have included a short description of the most common types of intestinal parasites.


are the most common type of intestinal worm. They are 2-4 inches long and resemble strands of spaghetti. They live in the small intestine, and may cause vomiting, diarrhea or weight loss. Larval worms also damage the liver and lungs while migrating through these organs on their way to the small intestine. Roundworms are transmitted via stools of other infected dogs or cats, or through the uterus of the mother dog to her unborn pups. Entire worms can sometimes be seen in the stools or vomitus of infested animals. They are long and skinny and about the size of angel-hair pasta.


are small, about once half inch long, worms that attach to the lining of the small intestine, causing blood loss and diarrhea. Puppies can become infected through the mother’s uterus before birth, or via her milk after birth. Older animals acquire hookworms through skin contact with the stools of other dogs. These worms can infect animals and people through the skin surface, such as the soles of the feet.

live in the large intestine. They are not as common as the other intestinal parasites but the disease they cause can be very serious. Bloody diarrhea and weight loss are the symptoms seen.

These worms are transmitted by ingestion of the stools of infested animals.
They are much more difficult to eliminate than other worms, requiring deworming initially, in three weeks, and again in three months. Additionally, it is recommended that they be placed on Interceptor as their monthly heartworm prevention. Interceptor helps prevent whipworms.


live in the small intestine, where the head attaches to the intestinal wall and produces a chain of segments. Mature segments containing eggs are passed with the stool, or may be seen around the rectum. They resemble small grains of rice. They may be acquired by the ingestion of raw meat, rodents or birds or, most commonly, through the ingestion of fleas. Flea control is essential to control tapeworm infestation.


are microscopic, one celled protozoal parasites, more like bacteria rather than “worms”. Puppies can pick these up from their mother and they can also be acquired by eating rabbit or other wildlife droppings. They are treated with antibiotics.


are also protozoans. They are very difficult to pick up on a regular stool check. Antibiotics or special de-wormers kill them but they are difficult to eradicate completely and often flare up with stress or other intestinal problems. They are contagious to humans and cause vomiting and diarrhea in both people and pets.


If a stool sample is positive for parasites, your veterinarian will prescribe an effective dewormer and set up an appropriate deworming schedule for you to follow to ensure eradication of all parasites. We usually recommend deworming twice, two weeks apart, however, this will vary with the type of parasite found. Please weigh your animal before picking up any wormer, to ensure that the proper dose is given. A stool sample should be checked again 4 to 8 weeks later, and again possibly 3 months later to ensure that your pet is not being reinfested by his or her environment.


Even if fecal testing does not detect intestinal parasites, because intestinal parasites are common in young kitten and puppies and there is the potential for human consequences, the Center for Disease Control recommends deworming of all puppies and kittens at least two times.