Published Online: September 16, 2016
Fungal spores are ever-present in outdoor air, but the types and levels of different species vary depending on the geographic location and weather conditions. Little is known about the effects that outdoor fungal spores have on asthmatic children and adolescents. Some studies have suggested that outdoor fungal spore species may be associated with child and adolescent asthma hospitalizations. Fungal allergy may contribute to this effect but it is unclear if this is the major risk factor or if there may be interaction with other factors such as viral infection. Few studies have examined the effect of outdoor fungi and asthma admissions at an individual level and none have investigated this effect among children who are infected with human rhinovirus (HRV) which causes the common cold and is also strongly associated with asthma admissions.
In a research paper recently published in The Journal of Allergy & Clinical Immunology (JACI), Tham and colleagues examined whether outdoor fungal spores were associated with asthma hospitalizations in children and adolescents while accounting for individual fungal sensitivity and whether HRV infection was present at the time they were admitted to hospital. They examined data from 644 children and adolescents who were hospitalized for asthma and participated in the Melbourne Air Pollen Children and Adolescent Health (MAPCAH) study in Australia. Detailed information about allergies and respiratory infections in participants and daily outdoor fungal spores (classified into 14 major types), grass pollen counts and air pollution during the study periods was obtained. They examined associations between outdoor fungal spores and asthma hospitalizations while accounting for allergies, HRV respiratory infection, and levels of grass pollen and air pollution, on the same day and up to three days prior.
The authors found that four allergenic species of outdoor fungal spores (Alternaria, Leptosphaeria, Coprinus and Drechslera) were associated with asthma hospital admission independent of having HRV infection. Some effects were also found for fungal spore exposure up to three days prior to admission. Associations with Alternaria, Coprinus and Drechslera were stronger in those who were allergic to Cladosporium which may be related to cross-reactivity between fungal species. These are new findings for this region.
Globally, asthma remains a significant public health issue and the outdoor environment is a major contributor to its aetiology. This research provides increasing evidence that outdoor fungal spores contribute to asthma hospital admissions. Investigation of their role in conjunction with other environmental factors requires greater attention.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.