21 Mar Internal Parasites

Internal parasites are those that infect the “inside” of pets. Unlike external parasites, we don’t see these parasites, but they can have devastating effects on pet and human health.

Heartworm disease is an emerging concern – with positive cases in Nova Scotia and the other Atlantic provinces in recent years. Heartworm has been diagnosed in all Canadian provinces and all American states. It is a blood-borne parasite transmitted by mosquitoes- an abundant summer inhabitant! An immature form of heartworm (microfilaria) is transmitted from infected animals to other pets when the mosquito takes a bloodmeal. Microfilaria go through a maturation process then migrate to the vessels of the heart and lungs. Here they mature into adult heartworms able to reproduce and release microfilaria into the bloodstream of the pet. Heartworm can be devastating and animals do not show clinical signs until late in the course of disease. The importance in heartworm testing is to identify positive dogs for early treatment AND to help prevent the spread of disease. Prevention is the key in keeping the disease from becoming more prevalent in our area. Dog owners should speak to their veterinarians about heartworm preventative. Cat owners need not worry as Heartworm disease has not been diagnosed in cats in our area.

Intestinal parasites (aka worms) include many different types including round, hook and tapeworms. Some of these infect pets only while others are said to be zoonotic and can be transmitted to people.

Roundworms are the most common intestinal parasite and are zoonotic. Most puppies and kittens are infected at birth or at a young age. A deworming series should be performed in all kittens and puppies. Adult pets should be dewormed on a routine basis as well. In pets, roundworms may cause vomiting, diarrhea and a “potbellied” appearance. Transmission to people is via the ingestion of roundworm eggs. The most important mode of transmission is contact with infective soil and sand in children’s play areas. Another transmission mode is direct contact with an infective pet. Once ingested by people, eggs develop into larvae. These larvae can travel from the intestinal tract to different parts of the body causing tissue damage. Larval migration through the eyes can cause vision problems and other ocular diseases.

Hookworm infections in animals occur when through the ingestion of eggs, via milk from the mother or as larva penetrate through the skin. Infected animals may exhibit weight loss, poor coat, vomiting or diarrhea. This worm is also zoonotic causing skin irritation in people when larva migrate through the skin where they eventually die.

Tapeworm infections are limited to your pet – transmitted to animals through fleas and hunting! They rarely cause any problems except for an itchy hind-end as “rice-like” segments of the worm pass from the anus but not esthetically-pleasing to humans.

The key to prevention/treatment of intestinal parasites is routine deworming especially during months of higher challenge (spring, summer, fall) along with annual fecal testing. Hygiene is of the utmost important as well – immediate removal of stool is vital along with the covering of sandboxes while not in use.

For more information on internal parasites, contact your veterinarian. Wishing you a happy and parasite-free season from everyone at Vetcetera Animal Hospital!