Roaches May Breed Allergies Too : Health: The creepy pests give most people the willies. A study has found that the critters may also cause more serious problems.
Long despised by housekeepers, the lowly cockroach is being targeted by scientists, who have found it to be a serious indoor cause of asthma and allergies.
The cockroach “is a risk factor people haven’t considered to date, in part because it’s not a socially acceptable topic for discussion,” said Dr. Robert G. Hamilton of the Johns Hopkins School of Medicine here. More than almost any other pest, cockroaches elicit feelings of guilt, revulsion and dirtiness.
Although cockroaches have been accepted as a source of human allergies for the last five years, Hamilton said, “only recently have we been able to prove it, and prove to patients that they may have a problem in their own environment.”
Hamilton, with Johns Hopkins doctors N. Franklin Adkinson Jr., Peyton A. Eggleston and Martin Chapman, proved the link between cockroaches and allergies by using new techniques that allowed them to isolate, identify and measure the presence of cockroach allergens, chemicals that trigger an allergic reaction.
Skin tests on 73 asthmatic children in the Baltimore area found that 49% were allergic to cockroach allergens. Of those children, 61% were found to be living in homes with cockroach allergens present, enough to establish a cause-and-effect relationship, Hamilton said.
The allergies can range from “the very mild--watery eyes and a runny nose--to . . . wheezing and respiratory problems that can be severe in some cases,” Hamilton said.
Hamilton’s research focused on two proteins released by German cockroaches (Blatella germanica), the most “cosmopolitan” of eight species common in American homes. “We don’t know yet exactly what (the proteins) are or what their functions are,” he said.
University of Virginia scientists say the substances seem to be secreted continually as the cockroaches walk about, perhaps as sex lures or as a sort of territorial marker. They are not limited to cockroach parts or droppings.
After being released by the cockroaches, the allergens cling to dust particles, which are then blown around the house and inhaled, touching off allergic reactions among sensitive people.
Only the most prevalent mold spores and the droppings of dust mites--microscopic spider-like creatures that consume the dead cells of human skin--rank higher as indoor risks to allergy and asthma sufferers, Hamilton said.
Cats and dogs also are potent sources of allergens, but because they are easily removed from the home, they are a less serious problem than mites, mold and cockroaches.
