Emerging Cockroach-associated Biocontaminants in Low-income Households - Project Summary/Abstract Asthma, a chronic respiratory disease, afflicts millions of people in the U.S. and exacts high financial burden on the healthcare system. As people spend most of their time indoors, allergic asthma and atopy are frequently induced by exposure to a variety of indoor biological allergens. Sensitization to cockroaches and chronic exposure to cockroach allergens are well recognized as important risk factors in the development and prevalence of asthma in children, especially in low-income urban and rural households. Exposure to bacterial and fungal toxins, such as endotoxins and glucans respectively, is also linked to pulmonary inflammation and exacerbation of asthma symptoms. A recent National Health and Nutrition Examination Survey study reported a strong positive correlation between the presence of cockroach allergens and endotoxins in dust sampled from the homes of asthmatic children. However, there is a conspicuous gap in our understanding of whether the microbes that cockroaches disseminate into the home environment re-shape the indoor microbiome and exposome, and consequently impact indoor environmental quality and health outcomes. Our long-term goal is to identify major cockroach-associated asthma triggers in the indoor environment, ascertain their impacts on the health of asthmatic children, and develop sustainable strategies to mitigate and abate their impacts. The goal of this exploratory study is to elucidate the causal relationships and linkage between the prevalence of cockroaches and several indoor pollutants of microbial origin. Preliminary results support the central hypothesis that perennial cockroach infestations degrade indoor environmental quality (IEQ) in high-risk low-income homes by producing not only a well-recognized cocktail of potent allergens, but also endotoxins, glucans, and mycotoxins that can exacerbate the impacts of the allergens as asthma triggers. The proposed approach includes two specific aims: 1) Determine the causal relationship between cockroach infestations and indoor microbial toxins , and 2) Determine the role of cockroaches in proliferation, vectoring, and sustaining microbes and toxins that are linked to respiratory disease and asthma . The project innovates by integrating in-home sampling with metagenomic, metabolomic, and proteomic approaches to identify novel asthma triggers that contribute to health disparities, and by using environmental interventions to quantify the effects of cockroach infestations on the prevalence of microbial toxins indoors. The impacts of this study include improving our understanding of the mechanisms by which cockroaches shape the indoor microbiome and identifying emerging biological pollutants that exacerbate respiratory health in low-income cockroach-infested homes. Future directions will explore 1) the roles and mechanisms of cockroach-associated microbial toxins in exacerbating the impact of allergens in a mouse model, and 2) the effects of targeted environmental interventions that eliminate cockroaches on reducing all cockroach-associated contaminants (allergens and microbial toxins) and improving health outcomes in asthmatic children.
