All those cute and affectionate dogs and puppies appearing in television commercials and news footage provide heartwarming scenes for their audiences. But there is another message that is not being provided: Affectionate licking by a pet occasionally can be hazardous to your health.

In recent weeks, two commercials appeared on prime time television illustrating what appears to be wholesome affectionate game-play with house pets.

One scene shows a laughing child having his lips and face licked by a cocker spaniel puppy. Another shows an attractive model kissing her dog on the head.

Clearly, advertising agencies have not heard of the potential for disease with that kind of contact with a dog or cat.

Dogs and cats are potentially capable of passing 30 different diseases on to humans. Most of these diseases are either innocuous or rare. One of these rare diseases is visceral larva migrans, which is caused by the passage of the dog or cat roundworm from these animals to humans.

Although there are no statistics on how many people get VLM annually, it is estimated that 50 percent of the dogs in the United States are infected with intestinal parasites, and the roundworm is the most common. The life cycle of this parasite is only completed in the dog or cat, but humans may be an intermediary host in the form of the larva.

Puppies are the most common transmitters of VLM to people, but 15 percent of older dogs actively excrete roundworm eggs. Any female dog that has ever had roundworms passes it on to all of her puppies in spite of any previous medicinal wormings.

In transmission to humans, the affected dog passes the egg to the human mouth; it then passes down the human's intestinal tract, bores through a layer of the intestine and passes into the circulation or migrates through the tissues. It can lodge anywhere in the body.

The disease is seldom fatal, unless, as the larva has in rare cases, it invades the muscle of the heart or the brain of the human. If the eye is affected, blindness may result. In milder cases, it can cause unequal deviation of the globe (crosseye) or reduced eyesight.

The eye form occurs more commonly in the older child and the visceral form in the 1-to-4 age group. The mildest form of VLM occurs in the skin and was originally referred to as the "creeping eruption."

Other symptoms may occur depending upon the movement of the larva: cough, fever, rash or inability to gain weight.

Until recently, the visceral form was mainly diagnosed on post mortem examination, but since the development of a recent laboratory test (ELAS) confirmation of this diagnosis has improved immeasurably, and pathologists are discovering that the disease is found more frequently than before.

Unlike many disease forms, VLM can be prevented by good hygiene and some veterinary attention for pets.

Mouth-to-mouth contact with any pet should definitely be avoided. The child's sandbox, used frequently by stray cats for bowel movements, should be closely monitored.

Samples of the pet's stool should be tested at least every six months by a veterinarian and more frequently if it has tested positive. Discussion of this potential problem should be included on the next health exam for your house pet if you are at all concerned.

A. Budd Fenton, DVM, has practiced veterinary medicine in the Washington area for over 40 years.