Editor’s Note: This article was reprinted with permission from Techletter, a biweekly training letter for professional pest control technicians from Pinto & Associates.

Asthma is the most common childhood disease in the United States, affecting up to 15 percent of children, mostly in inner-cities. We’ve known for many years that one of the primary causes of asthma in children is the presence of cockroaches. Cockroach droppings, shed skins, dead bodies and egg cases all shed allergens in the form of protein particles, which become airborne and are then inhaled. Some people have an allergic reaction to cockroaches with sneezing and a runny nose. But cockroach allergens can lead to a more serious asthmatic response in sensitive individuals. For inner-city children and the elderly, German cockroaches cause more cases of asthma than pets or dust mites.

Recently, several researchers have looked more closely at the role of house mice in childhood asthma. What they found was surprising. Mouse infestations cause more serious asthma symptoms than cockroach infestations. Mouse allergens are present at some level in most inner-city and low-income households and are common in high-rise apartments, older homes, mobile homes and inner-city schools. The older the structure, the more likely that mouse allergens are present. The allergens are found primarily in mouse urine and in mouse dander (shed skin flakes). Because mice dribble urine droplets as they travel, allergens can be anywhere.

In the most recent study, 284 children with asthma in a northeastern U.S. city were followed for one year. Dust samples were taken from their inner-city homes and their schools to analyze for various allergens. In schools, dust mite levels were low and cockroach and rat allergens were almost undetectable. However, mouse allergens were present in almost 100 percent of the school samples and at significantly higher concentrations than in the homes. The children with higher exposure to mouse allergen in schools had increased asthma symptoms and lower lung function. A related study of children in the Bronx, N.Y., found that children allergic to mice were more likely to have had at least one emergency department visit in the past year compared to children not allergic to mice.

WHAT CAN SCHOOLS DO? Asthma attributed to pest infestations in schools is a problem for the parents of asthmatic children since they have little control over the school environment where their children spend much of their day. In the home, bedding can be washed to reduce dust mites. Pet dander can be controlled and, presumably, cockroaches and mice can be eliminated. Should schools be routinely tested for allergens, and if so, how would levels be reduced? Because mice are active mostly at night, would most schools even know that they have a mouse problem?

Some national, state, city and non-governmental organizations have developed school-based asthma management programs that primarily rely on education to manage symptoms and reduce asthma-related school absences. The use of classroom HEPA air filters has been studied. What seems to be largely missing is a proactive integrated pest management approach in schools aimed at reducing the pests (now, mice) that are responsible for many asthma symptoms in schoolchildren.

WHAT CAN PMPs DO? If you have school accounts, you can understand the importance of thoroughly inspecting for and controlling mice. Too often, mouse management isn’t begun until mice are spotted in an account. Schools are prime candidates for preventive measures such as rodent-proofing of doors and openings around utility lines that enter the building.

Don’t limit your intensive mouse inspections to school accounts through. Give extra effort to mouse inspections in homes with asthmatic children or adults. Similar inner-city asthma studies in homes have found mouse allergens present in 95 percent of the homes tested. Allergens were found most often in kitchens, but also in children’s bedrooms. This means children are exposed to mouse allergens at school during part of the day, and then continue to be exposed at home during the remainder of the day, although generally at lower levels than at school.

REMOVING ALLERGENS. Unfortunately, eliminating the pests causing asthma doesn’t necessarily eliminate the symptoms for everyone. Allergens accumulate over time and are very difficult to remove from an environment, particularly when they are from pests that live (and die) in hidden places like wall voids or cracks and crevices.

Studies on cockroach allergen deposits in homes found that after successful elimination of the cockroaches, even the most thorough, professional cleaning did not eliminate all the hidden allergens. Enough allergen residue remained to still cause reactions in very sensitive people. This emphasizes the importance of not allowing cockroaches or mice to become problems in the first place. Prevention is key.

The authors are well-known industry consultants and co-owners of Pinto & Associates. To subscribe, visit www.Techletter.com.