To Your Health

A. Combantrin (the generic name is pyrantel pamoate) is often the first medication used to treat pinworms, hookworms, and roundworms because it is available without a prescription. Another advantage of pyrantel is that adults and children more than 2 years of age can all take the same dose. Of all types of worms, pinworm is by far the most common, and the most innocuous. The symptoms you describe fit with pinworm infection. See "To Your Health" in the Dec. 13, 2003, Austin Chronicle for more information on pinworms.

Contrary to popular belief, pinworms do not infect dogs or cats, and children who get pinworms do not get them from dogs or cats. Any long, thin worm segments associated with dogs are likely to be tapeworms; hookworms and roundworms look quite different from pinworms or small tapeworms. A species of pinworm does infect horses, but since parasites usually adapt themselves to their host, apparently these pinworms are not transmitted to humans.

Due to the economic rewards of keeping valuable thoroughbred horses in excellent health, such horses have been used as experimental animals to refine worming techniques. Such studies should help us understand the safety of pinworm medication and how to most effectively control pinworms in humans. The question of how often pyrantel can safely be used to deworm your family may be answered by an article published in Veterinary Parasitology in 1996. Daily administration of pyrantel appears to be safe for both yearling foals and adult horses. Both daily and monthly administration controlled the pinworm egg count in adult horses, but both failed in younger horses. If this observation in horses can be transferred to humans, it appears that keeping children completely free of pinworms is a difficult task even when medications like pyrantel are used continuously. Your present practice of treating your family when any of them exhibits symptoms seems ideal.

It may be unnecessary to treat the dog along with the rest of the family if you only suspect pinworms and have no suspicion of roundworm or hookworm infection. You can spot roundworms in your dog's feces, and you should carefully protect your children from contact with your dog if roundworms are found. Dogs can be infected with roundworms and pass them on to humans through their feces, but it takes approximately two weeks after being passed for the eggs of this parasite to become infective to humans. If humans inadvertently ingest roundworm eggs, the eggs hatch in the human's intestinal tract, and then the immature roundworms, rather than maturing into adult worms, migrate to other tissues (lungs, liver, brain, etc) and become a serious condition. With this risk in mind, many cities have passed "pooper scooper" laws that require owners to immediately clean up their pet's feces from public property.