Pearls Asthma and the Diversity of Fungal Spores in Air

The diversity of fungal spores in air is vast ([1,2], Figure 1), but research on asthma focuses on a handful of easily identified, culturable species. Ecologists are developing new tools to probe communities and identify the full complement of fungi in habitats. These tools may enable identification of novel asthma triggers, but scientists involved in public health or medicine rarely interact with mycologists focused on ecology. With this primer, my aim is to facilitate communication by providing doctors with a basic, modern guide to spores, by teaching mycologists the essential facts of asthma, and by providing patients with a succinct summary of what is known about spores and asthma. By highlighting the use of emerging metagenomics technologies in ecology, I intend to illustrate how these tools might be used to more thoroughly understand the potential diversity of fungi involved in asthma. What Is Asthma? Asthma is a complex disease without a single cause, defined by its symptoms [3]. Wheezing, chest tightness, and breathlessness are triggered by airway inflammation. The natural histories of asthma are diverse and involve both genetic and environmental param-eters. For example, children with variants of the ADAM33 gene are at risk for asthma [4], while attendance at day care in the first six months of life and the presence of older siblings appear to protect against asthma [5]. Allergies are intimately associated with asthma. Asthma can result from direct inhalation of allergens, but atopic asthmas are caused by the body’s interaction with allergens outside of the lungs. Asthma is a public health burden, and the prevalence of asthma is increasing [6]. In countrie