Disease caught from animals - toxoplasmosis and viral infections

Pediatrics for Parents, May, 1991 by Rosemary Iconis

Most of us would find it difficult to picture a scene more heart-warming than that of a cute little puppy or kitten licking the face of an adoring child. However, should such a sight be viewed simply as a touching display of affection or as a serious health risk?

There is no doubt that animals can be an invaluable source of companionship and love. Consequently, in the United States alone, there are more than 60 million dogs and cats who are household pets. There are those who choose to lay the blame for a wide range of human diseases on them, while others refuse to believe that animals present any health risk at all. When considering the potential health hazard of animals to human beings, it is important for us to remember that we must not only be concerned about our own pets, but other people's pets and stray animals as well.

Toxoplasmosisos And Other

Infections Caused By

Parasites

Avoidance of infection by the organism which causes toxoplasmosis is particularly important in two segments of the population - pregnant women, because of the effects of toxoplasmosis on the unborn child and anyone with a deficient immune system because of their increased risk of developing serious, and sometimes fatal, complications. Unfortunately, a tremendous amount of misunderstanding surrounds the true role cats play in the transmission of the disease. Cats, as well as humans, can become infected by eating undercooked meat. Ideally, cats should be fed only cat food. If they are given meat, owners should be sure that it is properly cooked.

If a cat eats an infected rodent or bird, the parasite multiplies in the cat's intestines and microscopic eggs may be passed in the feces. However, the eggs must sit in the feces at room temperature for at least one day before they go on to the stage at which the infection may be passed on to humans. So, the litter box should be cleaned on a daily basis. In addition, children should be taught not to handle animal feces. Sandboxes should be covered so that what the cat probably sees as a giant litter box does not become a storage place for animal feces. Taking such precautions minimizes the risk of cat to human transmission. Have no fear of hugging or petting your cat. Because of the cat's impeccable grooming habits, fecal matter is rarely found on cat fur.

Toxoplasmosis, in an average risk adult or child, is a self-limiting disease which means that it runs its course of flu-like symptoms and generally requires no treatment.

Two other fairly common parasites are known as dog roundworm and cat roundworm. When a human ingests the eggs of these roundworms, they hatch and enter the bloodstream, where they may spread to almost any organ. However, their most common destinations are the liver, lungs, heart, brain, or eye. Since the eggs are found in the dog or cat's fecal material, its ingestion by humans may produce the disorder. Animals often like to bury their excrement in the dirt, which results in infected soil. Some children put dirt, as well as other non-food substances, in their mouths. This is a condition known as pica. Thus, eating infected soil is one way in which eggs may be taken into the body. Children, particularly one to five year olds, are particularly susceptible to this ailment because of their close contact with pets and their poor sanitary habits.

Symptoms may be vague. For example, the child may have a slight cough if the organism has affected the lungs. In the most serious form, called ocular larval migrans, hatched eggs get into the eye of the child. The concern is that this treatable disorder can look very similarly to a non-treatable type of cancer of the eye that can occur in children.

Although ocular larval migrans can be successfully treated with medication, the far better option to take is prevention. Veterinarian, Dr. Marcia Landefeld, suggests several preventative tips: teach your children not to handle animal feces and to wash their hands after having contact with animals; remove fecal material from the litter box daily, and flush if down the toilet; closely supervise your children, especially those with pica, when they play outdoors, particularly in parks, sand boxes, and at the beach which are common sites for feces buried in the soil or sand; and bring in your pet for regular veterinary screening exams and deworming.

Viral Infections

Can you catch a cold or sore throat from your pet? Probably not -- generally, colds are thought to be species specific, meaning that dogs only catch colds from other dogs, cats from other cats, humans from other humans, etc. While the research is not clear yet, chronic streptococcal infection may be an exception to the rule. So, while it's not common, it's possible that this infection is transmissible if, for example, your dog or cat licks your child's face or they share an ice-cream cone.

Cats may develop leukemia. It is caused by the feline leukemia virus and is seen only in cats. It's not the same as leukemia which occurs in humans and research shows that it is not transmissible to any other species, including humans.