Cockroaches Are a Factor in Severe Urban Asthma, Researchers Warn

Five years ago, a team of researchers set out to determine why asthma is such a severe urban health problem.

They penetrated the worst neighborhoods in seven big cities and spent $17 million vacuuming up dust, administering allergy tests and poring over the medical records of poor children.

In a few months, their first formal reports will hit the medical journals. Perhaps 50 papers eventually will be published. But in the end, the piles of data largely boil down to a single nasty word:

Cockroaches.

The surprising result is likely, in time, to change the way the medical world thinks about childhood asthma. Already, those in charge of the study view these bugs as a serious public health hazard.

Dr. Richard Evans, an asthma specialist at Children’s Memorial Hospital in Chicago, hardly paused when asked to name the single most urgent step to prevent the problem he treats every day.

“The one thing I would do is help people eliminate cockroaches,” he answered.

Certainly, other problems besides roaches contribute to asthma among the poor--decrepit housing, the so-so quality of doctoring at some Medicaid clinics, fragmented families where no one adult takes charge of children’s health care.

Furthermore, asthma is hardly restricted to the welfare class; it is the most common chronic illness of childhood and seems to be increasing everywhere.

But the disease takes its greatest toll in the nation’s poorest locales. In New York City, for instance, 8.6% of children in the Bronx have asthma, double the rate for urban residents nationally. Seeing people on street corners taking puffs from asthma inhalers is commonplace.

Kids’ asthma usually is caused by an allergic reaction to a substance that makes them wheeze, called an antigen. Of all the possible asthma-provoking materials youngsters encounter in homes, cockroach antigens appear to be the most powerful.

Identifying the antigens in poor children’s asthma was a top goal of the National Cooperative Inner City Asthma Study. At the start, the experts assumed it would turn out to be the dust mite, the ubiquitous microscopic bug that, along with cats, is the leading cause of asthma in the suburbs.

But no. After testing 1,528 children under age 10 and visiting half of their homes, the leading antigen by far was proteins in the droppings and carcasses of Blattella germanica, the German cockroach.

It turned out that 38% of the asthmatic youngsters were allergic to roaches. But even more surprising to the doctors involved were the staggering quantities of cockroach crud in these children’s apartments.

A hint of wonder, even horror, tinges the researchers’ voices when they talk about where they found cockroach residue.

Levels often were sky-high in kitchens, of course, and bathrooms. But the stuff was everywhere in the apartments--even the beds.

“There were huge levels of cockroach antigens, much higher than has ever been reported,” said Dr. Peyton Eggleston of Johns Hopkins University, one of the researchers. “Almost every house had detectable levels.”

This is not much of a surprise to Keith LaRue, an exterminator for American Pest Management of Tacoma Park, Md., who helped gather samples for the study. One recent beautiful spring morning, he made his rounds through some of the most depressing neighborhoods in the nation’s capital.

His first stop was Martin Luther King Boulevard in southwest Washington, a dark one-bedroom basement apartment in a big brick complex. Stomach-churning stink filled the dead air.

“What you smell,” he said simply, “is roach.”

The kitchen walls were speckled brown with cockroach droppings. LaRue opened a cupboard and lifted a frying pan. Four or five roaches darted away.

More ran over the plates, around the cereal boxes, under the refrigerator, into the full garbage can, up the walls and into the crack between the door trim and the ceiling. On the floor were too many to count--live ones, dead ones. It hadn’t been swept in a long time.

LaRue moved quickly from room to room, stepping around bags and piles of clothes and junk, squirting roach bait from a toothpaste-sized tube.

It was 9:30 a.m. In the bedroom, a young woman and her two babies slept on one of the three beds. None of them stirred while LaRue did his work.

Meanwhile, in the living room, two 50ish men watched a talk show on the sofas where they had spent the night.

John, who called himself a boarder in the apartment, was thinking about moving out.

“All those roaches,” he explained.

He and his friend Joseph offered a few details about the woman sleeping in the next room: She’s Tina, she’s 22 and she has asthma.

Back outside, breathing the fresh air, LaRue looked for someplace to wash his hands. “You can’t be anything but sick living in those conditions,” he said.

LaRue guessed the apartment was home to maybe 5,000 German cockroaches. Nothing special, though. “This is typical in this area,” he said.

LaRue may have underestimated. Rick Brenner, a cockroach expert at the U.S. Department of Agriculture, systematically counted the German cockroaches in about 1,000 low-income apartments in Gainesville, Fla. The median number per unit--13,000.

The levels of infestation are particularly important because Dr. Alkis Togias of Johns Hopkins, who is looking at a cross-section of teen-age asthma victims in Baltimore, found that the more cockroaches in victims’ homes, the greater their chance of being allergic to roaches and the more severe their asthma.

Half of the poor asthma victims in his study were allergic to roaches, compared with just 10% of adolescents from upper-income families.

For years, people have speculated that an increase in asthma is a result of outdoor air pollution--but that is almost certainly not the cause. Air quality has improved substantially in recent decades for everyone. Neither is cigarette exposure, since smoking too has fallen off.

“All the things that seem to make asthma worse are decreasing. So asthma should be getting better,” said Dr. Peter Gergen of the National Institute of Allergy and Infectious Diseases, which sponsored the inner-city study.

The opposite is happening. The proportion of Americans who say they have asthma has risen 45% in the last decade; it now stands at 14 million to 15 million, about a third of them under age 18.

Deaths are relatively rare--3,850 for people under age 25 between 1980 and 1993--but they are increasing as well.

The reason for this scourge may be the same for the poor and well-off alike--exposure to antigen-laden indoor air.

All homes built since the 1960s--and that includes lots of low-income housing--are tight and well-insulated. But a draft-free home may not be entirely a good thing.

“As we build more energy-efficient structures, humans now breathe less fresh air than they ever have,” Brenner said.

With little air exchange, antigens from bugs, molds, cats and dogs build up inside the house. Wall-to-wall carpeting, another feature of new construction, grows heavy with trapped antigens, even in clean-looking homes.

People stir this stuff up whenever they walk around. And as the indoor air gets worse, they breathe more of it, because all of us--especially children--spend so much time inside.

Television and video games are not the only reason.

“In the inner cities, children who used to be outdoors are now indoors because parents are afraid to let them outside,” said Dr. Thomas Platts-Mills of the University of Virginia.

Any city apartment may have a few roaches, no matter how fastidious the tenant. But serious infestations almost always mean people are leaving food around.

Roaches go where they can find dinner--dirty dishes in the sink, open cereal boxes, leftovers on the counter, garbage that sits around for days.

And old apartment houses often have cracks and holes that let roaches travel around freely, although those who know roaches say the bugs can quickly overcome new buildings, too, if given a chance.

“Cockroaches are good at one thing, and that’s surviving,” said Jay Nixon, LaRue’s boss at American Pest Management. “If you throw in unlimited food, moisture and harborage and don’t try to control them, in six months’ time you’ll have lots of roaches. It just explodes.”

To Eggleston and others, the discovery of cockroaches’ part in asthma is actually good news, because it means something can be done. As a start, Eggleston has a new project to see if teaching apartment dwellers these steps will cut down on roaches and the disease they bring.

“I am very positive about it,” he said. “We may not totally eliminate it, but I bet we can reduce exposure significantly, and I think it may have an effect on asthma.”

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Evicting the Roaches

Experts say tenants can keep their units reasonably roach-free, even if other apartments in the building are infested:

* First, kill the roaches with sprays and poison baits.

* Wash down all the surfaces to get rid of roach antigens.

* Keep all food out of roaches’ reach.

* Put out roach traps to catch the strays that wander in.

Associated Press