Pet Ownership: Risky Business?

by Food and Drug Administration (FDA)

Sharing homes with pets is a way of life for many Americans at least 60 percent by some estimates. And the companionship, affection and trust of pets can provide distinct health benefits for their owners.

Studies described at a 1987 National Institutes of Health workshop linked life with a pet with: higher survival rates in patients with heart disease increased self-confidence and independence in psychiatric patients improved ability of children to interact with others.

But if you're a pet owner or thinking about becoming one you need to consider that these trusted companions can also present some very real health risks. In addition to giving affection, the millions of household cats, dogs, birds, reptiles, and other small animals can impart diseases to their owners as well.

Zoonosis is a disease communicable between vertebrate animals and humans, and between different species of animals. Some of these diseases have been known for a long time. The ancient Greeks, for example, were aware that rabies could be transmitted through dog bites. And the bubonic plague that decimated the population of Europe in the 15th century bridged the gap from animals (mainly rodents) to people by way of fleas.

Growing List

The list of known animal-transmitted diseases constantly changes, as improved diagnostic techniques identify zoonoses previously mistaken for more common exclusively human diseases. For example, in the 1960s, the role of felines in transmitting toxoplasmosis in their feces was discovered. In addition, travel to more remote parts of the world by people and the increased international commerce in exotic animals have added to the list of zoonoses.

Fortunately, most zoonoses are rare, and almost all can be treated once a diagnosis is made. Here's a list pet owners should be familiar with:

Toxicara canis, or roundworm, is a parasite that is carried most often by nursing dogs and their puppies, and less often by cats. Scientists estimate that virtually all puppies have roundworm.

Because children like to play in the dirt, they are most vulnerable to picking up roundworm; and the disease is transmitted through contact with the dog's feces or soil contaminated with it. Symptoms of roundworm in humans are fever, headache, cough, and poor appetite.

So prevalent and well-established is the dog roundworm in our pet population that roundworm-free puppies can only be obtained by raising several generations in isolation or administering repeated high doses of anthelmintics (a type of drug that gets rid of intestinal worms) to the pregnant mother dog.

Diana Post, V.M.D., a veterinarian with the Food and Drug Administration, explains that much of the roundworm infection of the mother dog is non-egg-producing and does not contaminate the environment. However, it is more resistant to elimination with anthelmintic drug treatment than the egg-producing contagious type of infection found in the puppies. Egg-producing infections may be found in adult dogs, although less frequently than in puppies.

For this reason, many parasitologists recommend that veterinarians consider treating very young pups two to three weeks after birth (the time they would be expected to pass infected eggs in their stool). This can be risky, though, because immature animals, including dogs, are very sensitive to any drug therapy. Such treatment should only be undertaken if it is recommended by a veterinarian.

Both puppies and people can be treated with anthelmintics, a class of drugs used in both human and veterinary medicine.

Toxoplasmosis is a disease produced by infection with the one-celled animal Toxoplasma gondii, a parasite capable of surviving in many different animal species. It is sometimes spread to humans through cat feces or dirt contaminated with cat feces. All breeds of felines, even wild jungle cats, can become infected with Toxoplasma gondii. The cat becomes infected by killing and eating small rodents. But most people contract toxoplasmosis not from cats but from eating raw or undercooked meat. Meat becomes infected because cows and sheep graze in pastures that have been contaminated by infected cats.

Toxoplasmosis infection is common and can infect almost all species of warm-blooded animals. But most infected people do not develop symptoms because, according to most estimates, about one-third of the world's population has antibodies to the disease. (Infected persons with immune system defects or those receiving immunosuppressive therapy may develop a serious form of the disease.)

Symptoms in humans are fever, headache, swollen lymph glands, cough, sore throat, nasal congestion, loss of appetite, and skin rash. The disease can be treated with antibacterial drugs.

Expectant mothers especially those in the first three months of pregnancy should be especially alert to the possibility of this disease because toxoplasmosis can cause miscarriage, premature births, or blindness in unborn children. For this reason, pregnant women should not clean a cat?s litter box and should avoid eating raw or poorly cooked meat.

Ringworm is a skin disease caused by a fungus, not by a worm as the name would imply. Dogs, horses, cows, and most commonly cats pass the disease on to humans. Only children pick up ringworm. Long-haired kittens seem especially prone to ringworm, says Post. The fungus infects cat hair, and a youngster can contract the disease by petting the kitty. Ringworm can be diagnosed by exposing the animal to a Wood's lamp, an ultraviolet light in which the infected hairs look green. Treatment for ringworm should be prescribed by the veterinarian caring for the pet.

In humans, infection usually occurs on exposed parts of the body, particularly the scalp, appearing as an inflamed, scaly lesion. Iodine-based soap or anti-fungal drugs cure the problem in humans.

Psittacosis (parrot fever) is a bacterial disease that affects 130 species of domestic and wild birds, most commonly pigeons, ducks, turkeys, chickens, and parrots. Humans can get the disease from parrots or parakeets through contact with their feces and the dust from their feathers that accumulates in cages.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.