The primary objective of the Childhood Asthma REduction Study (CARES) is to evaluate the effectiveness of a novel cockroach eradication method, shown in prior studies to drastically decrease cockroach allergen levels, in reducing asthma morbidity in children with moderate to severe asthma who are both allergic and exposed to cockroach allergen. Additionally, the study will characterize relationships between cockroach infestation and other environmental allergen exposures, and asthma morbidity, as well as consider dynamic relationships between cockroach counts and observed allergen reductions over time; and use study data to identify mechanisms such as cleaning behaviors that may influence those relationships.