Does Your Pet Have Worms?

Of the ailments pets can suffer from, worms may not be the most dangerous to an animals health, but they are one of the most unpleasant from an owners perspective. Not only can they cause weight loss and mild diarrhea in your pet, they are also unsightly and some of them can be transmitted to humans.

There are 4 different types of worms that affect dogs and cats: roundworms, tapeworms, hookworms and whipworms. These very greatly in both the part of the intestinal tract that they live in and the effect they have on the animal.

Roundworms (Toxocara species)

These worms are commonly seen in young dogs and cats. The adults live in the small intestine and the eggs are passed in the feces. Animals are infected by eating other infected animals (e.g. mice, rats), eating the feces of other animals or, in puppies and kittens, via their mothers milk. Eggs are passed in the feces 3 weeks after infection. Infection with roundworms can cause a poor hair coat, weight loss (or lack of weight gain in puppies/kittens), a pot-bellied appearance, and diarrhea. Worms are sometimes vomited up or seen in the feces. Treatment is with an oral deworming medication with a follow up dosage in 3 weeks to catch the next generation that were eggs or larvae at the time of the first dosing.

Roundworms can infect humans, not usually in the adult form, but in their larval form. In a few cases children who ingest the eggs can suffer eye damage or blindness because the worm larvae move through the body causing damage to the tissues. This disease is called Visceral Larval Migrans.

Tapeworms (Dipylidium and Taenia species)

Tapeworms are long flat white worms composed of many segments that live in the intestines of dogs and cats. There are 2 main types that affect dogs and cats, Dipylidium and Taenia species. Dipylidium is obtained by the animal eating an infected flea whilst grooming (licking) itself. Taenia on the other hand is transmitted by eating infected small mammals (rats and mice), or by eating the feces of infected animals. Cats that hunt and dogs that live on farms are the highest risk. Diagnosis is by visualization of the small, rice-like worms in the feces (most common method); or seeing the eggs on a fecal flotation exam. The eggs and worm segments are inconsistently shed in the feces, so just because you cannot see any in your pets stool does not guarantee that your pet is not infected. Nor does a negative fecal flotation exam completely rule out the existence of a tapeworm infection. Clinical signs are rare since tapeworm infection rarely causes a problem. Some clinical signs can be a dull coat, an itchy anus, diarrhea or lethargy. Treatment is via oral deworming medication, an injection or a spot-on.

Tapeworm infection of humans is not common but can occur occasionally, usually in children who have ingested a flea which contains the larvae of the tapeworm. Adults can become infected with tapeworms by eating infected meat that is not cooked properly.

Hookworms (Ancylostoma species)

These worms are most commonly seen in young dogs and cats. Adult worms live in the small intestine, with the eggs passing out of the body in the stool. Animals become infected with hookworms by the following routes: eating infective eggs or larvae, penetration of footpads or skin by larvae, transmission through the milk while nursing young, or transmission from the mother into the fetus while still pregnant. It takes three weeks from the time of infection until eggs are passed into the feces. Hookworm infection can cause a severe and sometimes fatal anemia in young, weak, or malnourished animals. Clinical signs are weight loss, diarrhea, and bloody feces. Worms are occasionally seen in the feces. Treatment consists of oral deworming medication and correction of any anemia. A follow up treatment is given 3 weeks later.

Hookworm larvae can penetrate human skin and potentially cause a skin problem called Cutaneous Larval Migrans. No one should be barefoot for 5-7 days while the pet is being treated for hookworms.

Whipworms (Trichuris species)

This worm affects dogs 3 months of age or older. The adults live in the large intestine and eggs are passed in the feces. Diagnosis can sometimes be difficult because whipworms are not prolific egg-layers. Infection is via fecal-oral transmission. Eggs do not appear in the feces until 3 months after infection. Clinical signs that can be seen are weight loss and diarrhea, with or without blood. These worms are usually not seen in the stool. Treatment consists of an oral deworming medication with a follow up treatment in 3 months.

Treating your pet

Regardless of whether your pet is an indoor or outdoor creature, you should deworm them regularly to keep good hygiene. Many indoor cat owners believe that since their cats are not hunters, there is no way they could have acquired worms. However, the author has seen many indoor cats with fleas (brought in on the owners clothing or shoes most likely) and many fleas are infected with the tapeworm Dipylidium. Therefore even purely indoor cats can be carrying worms.

Puppies and kittens should be wormed every 2 weeks from 4 weeks of age up until 12 weeks. The worms they would be carrying at this age are roundworms, ingested via their mothers milk, so the recommended treatment is to treat with the drug fenbendazole (Panacur), which is available as a liquid, as sachets of granules or as a paste in a syringe.

Dogs and cats greater than 12 weeks old can be dewormed using conventional worming tablets. This should be done every 3 months for optimum protection. There are a whole range of products out there, but the strongest and most effective ones are always those purchased from a veterinarian. Products purchased over the counter from supermarkets or pet shops will often only protect against one of the types of worm and not the others, or will only provide 1 month protection rather than 3.

Here are some useful tips on how to keep your pet worm free:

1. Adult cats and dogs should be dewormed with a veterinary licensed product every 3 months.
2. Over the counter deworming medications may not always be effective.
3. Prevent your pet from eating rodents such as mice, rats and rabbits.
4. Prevent your pet from eating earthworms (roundworm infection).
5. Prevent your pet from eating feces (tapeworm infection).
6. Remove feces from your lawn, street, or kennel daily.
7. Exercise your pets in grassy areas not frequented by other animals.
8. Control fleas! (Fleas carry Dipylidium tapeworm)
9. Deworm females before breeding and again after whelping to prevent infection of newborn puppies/kittens.
10. Deworm puppies and kittens every 2 weeks from 4 to 12 weeks of age.