County health officials have reiterated a warning--first issued last summer--that house cats in a 12-square-mile area north of downtown Los Angeles may inadvertently become carriers for a low-grade form of the fever disorder typhus.
Health officials advise cat owners to take aggressive steps to control fleas on their animals and in their yards. But a variety of experts say that, while cats emerging as typhus carriers is a new wrinkle in public health, house pets--despite sometimes draconian warnings in the media--remain generally quite safe to handle and even share a bed with.
Good advice for loving cat and dog owners, one prominent veterinarian said, is, while it's generally all right to sleep with your pet in close proximity, "don't kiss your dog or cat on the mouth. You don't know where that tongue has been."
Periodically, noted several veterinarians and medical doctors, alarms are sounded about pet health and diseases that can be transmitted to humans. The question has even been responsible for at least one major controversy: Whether pregnant women should have any contact with cats and, if so, how much. The controversy stems from disagreement over the means of transmission of a disease called toxoplasmosis, a sometimes-serious parasitic infection that can be passed by a mother to her unborn child.
But the reality, these experts agreed, is that many possible pet-related disorders have little more than a theoretical danger to humans. Basic hygiene--particularly keeping children out of contact with pet feces or outdoor settings contaminated by cat and dog droppings--can avert most pet-related disease in humans. In the case of toxoplasmosis, there is controversy over whether it is more common to get the disease from contact with cat feces or by handling or serving uncooked meats.
Still, there's nothing wrong with caution of the type advocated in a medical journal editorial by a veterinarian employed by the U.S. Department of Agriculture. Somewhat facetiously, Dr. William Hubbert urged two years ago that, just as cigarettes carry a health warning label, perhaps it would be appropriate to stick a little tag on dogs, cats and even snakes and birds that says: "Caution, this pet may be a hazard to your health."
The immediate concern in Los Angeles County is with a modest outbreak--first identified in 1984 and 1985--of cases of so-called murine (meaning "flea-born") typhus that appears to be limited so far to a confined area including the Los Feliz, Silver Lake, Mount Washington and Eagle Rock neighborhoods in the city, the southern portion of Glendale and parts of South Pasadena.
Nineteen cases were reported in the county in 1984 and 1985--14 of them in the affected area, said Art Tilzer, head of a health department unit that tracks disease transmission pathways. None of the cases was serious. No episodes have been reported in 1986, Tilzer said, but he and physicians questioned by The Times agreed that, because symptoms of murine typhus are similar to a bad cold, the disease is often misdiagnosed.
Tilzer said the health department assumes there have been cases of the disease of which the agency has not become officially aware. "Conditions are still being monitored closely," Tilzer said after the department published a renewed notification of the possible outbreak last month in a newsletter for physicians. "We were expecting some additional cases, so this may be the slowing of a trend," he said.
Urging caution, health officials added that murine typhus is a far less serious disease than the so-called epidemic form of typhus and that both of those disorders are totally unrelated to typhoid fever, even though the names are a bit similar.
Murine typhus is characterized by chills, headache and fever, and there is sometimes a skin rash. In most patients, the fever disappears on its own after about 12 days, and fatalities are rare--though they have sometimes been reported in elderly patients. There is no vaccine. In epidemic typhus, on the other hand, symptoms are more severe and fatality rates can reach as high as 60% in older patients.
It isn't certain exactly how cats in the affected Los Angeles area neighborhoods entered the typhus transmission chain initially, but county health officials noted that murine typhus carriers include tree rats and possums--both species with which house cats in hillside neighborhoods routinely come in contact.
It turns out, said Tilzer, that while there are several flea species common in Southern California, the variety that transmits typhus is the same type that is attracted to cats. Both 1984 and 1985 were severe flea years, though 1986 does not appear to be as bad--though some cats (not to mention their owners) in the affected neighborhoods might disagree.
Importance of Flea Control