An army of architects, immunologists, epidemiologists and medical anthropologists has begun an ambitious attack on a ubiquitous plague: cockroaches.
The bane of urban dwellers, the cockroach has long been implicated in spreading disease-causing microbes to people by contaminating food or cooking utensils. But now scientists are finding that 10 million to 15 million Americans are allergic to cockroaches.
And researchers say the problem is getting worse.
Reactions range from a runny nose and skin irritation to difficulty breathing. People who are very sensitive can go into life-threatening shock, the researchers say.
At the Department of Agriculture's Insects Affecting Man and Animals Research Laboratory in Gainesville, Fla., scientists are monitoring the insect's behavior.
They are studying how different types of construction and airflow patterns affect cockroach concentrations. And they are freezing and grinding up roaches and extracting proteins in a complicated search for the offending allergens.
"The more we know about the enemy, the more likely we will be able to defeat it," said Richard J. Brenner, an Agriculture Department entomologist who heads the effort in which research is conducted from purposely infested buildings at the University of Florida in Gainesville.
Every year, homeowners and apartment dwellers spend about $1.5 billion on pesticides, but so far cockroaches have resisted every assault by nature and man.
In a study of six apartment complexes in Florida, Agriculture Department researchers found that about half the 1,022 apartments harbored more than 13,000 German cockroaches each. Dr. Brenner said that in those apartments, pest control, if provided, was with the cheapest, most common pesticides, to which many cockroaches are resistant.
Researchers believe that developing an allergy to cockroaches is dependent on genetic predisposition, large infestations and .
chronic exposure to certain cockroach proteins that adhere to dust particles and become airborne.
Studies by Bann C. Kang, chief of allergy and clinical immunology at the University of Kentucky Medical Center, show that exposure to these cockroach allergens can lead to a severe asthma attack in 61 percent of asthmatics.
Studies have found that more than a third of people with other allergies are also hypersensitive to cockroaches and that even 12 percent of people without any histories of allergies are allergic to some roaches. Hypersensitivity to cockroaches is even more common than such reactions to ragweed, Dr. Kang has found.
Dr. Brenner said that the steady increase in reports of cockroach allergies over the past 25 years is partly a result of efforts to make homes more airtight. Cockroaches, it seems, like dark, cozy spaces where there is warm, moist, stagnant air. Attics and wall voids are perfect.
In a recent study, Dr. Brenner and Kathleen Barnes, a medical anthropologist at the University of Florida, compared the quality of home construction with the incidence of allergy in the &L Dominican Republic, where homes range from huts to luxury apartments.
They found that the more airtight and better-made the home, the greater the incidence of cockroach allergy. Better-built homes apparently offer cockroaches a more comfortable habitat and allow allergens to accumulate.
Most apartments and homes in this country are fairly airtight, so increasing ventilation in areas where cockroaches congregate might be a key strategy toward eliminating the indoor pests.