Parents who see mice scurrying across their floor should be worried about more than just an impending scream from their children. Mouse allergen, in the form of mouse urine or dander, is widely distributed in the inner city and may be a significant contributing factor to the childhood asthma epidemic in urban areas, according to two studies by Johns Hopkins researchers published in the December issue of the Journal of Allergy and Clinical Immunology.

"Before these studies, mice weren't widely recognized as an allergen in homes," says Robert Wood, M.D., associate professor of pediatrics at Hopkins and lead investigator of both studies. "Now we know that houses are full of it, and we were surprised that mice turned out to be even more important in inner-city asthma than cats, dogs or dust mites. While cockroach is the more important inner-city allergen, mouse is second in line. Doctors need to take mouse allergen into account when evaluating kids with asthma."

In a study of eight cities, the scientists discovered that 95 percent of all homes in the study had mouse allergen in at least one room; Baltimore topped the charts with 100 percent. Eighteen percent of the children were allergic to mice and those children tended to have more severe asthma. Finally, they found that the more a person was exposed to mice, the greater the chances that future rendezvous with these rodents would cause a reaction.

For several years, researchers have known that cats, dogs, dust mites and cockroaches can cause allergies that trigger the wheezing and constricted airways of asthma. But while doctors have treated people who work with mice in laboratories for allergies to the furry creatures, until now, not much was known about mouse allergy in the general population.

To fill this knowledge gap, Wood and his colleagues turned to data from the National Cooperative Inner-City Asthma Study, (NCICAS), a multicenter study of 1528 children. First, the researchers analyzed
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Contact: Kate O'Rourke
korourke@jhmi.edu
410-955-8665
Johns Hopkins Medical Institutions
10-Dec-2000