Mould Allergy in Schoolchildren in Relation to Airborne Fungi and Residential Characteristics in Homes and Schools in Northern Norway

Abstract

During winter, airborne microfungi were collected from the homes and schools of 19 children sensitized to house dust mites (HDM) and 19 non‐atopic control children in the community of Sør‐Varanger, northern Norway. The samples were cultivated and microfungal growth was identified microscopically. Indoor humidity, temperature, carbon dioxide (CO2), allergic symptoms and sensitization were registered. Symptom data and information concerning sociodemographic and housing conditions were obtained using a questionnaire. Penicillium was the most common microfungus in both homes and schools, followed by different yeasts, Aspergillus, Cladosporium and Mucor. The number of infected homes was equal in the HDM‐sensitized and in the control group, but the mean aerospore counts were higher in the HDM‐sensitized than in the control group. The lowest aerospore counts were found in the schools. High airborne spore counts appeared to be related to high indoor humidity. Only four children were sensitized to fungi, and these children were also sensitized to other allergens, such as animal dander and pollen, and suffered from asthma, allergic rhinoconjuncitivits (AR) and atopic dermatitis (AD). Three of these four children also had high counts of aerospores in their homes. However, no consistent association between mould growth and sensitization to moulds could be observed. The health implications of indoor fungal exposure may be multifactorial.

Is the risk of allergic hypersensitivity to fungi increased by indoor exposure to moulds?

“…To eliminate this effect in our study, the quantity of mould growth and the selected health outcomes were measured using objective methods. Among the microorganisms isolated in the houses with mould contamination, A. alternata, C. cladosporioides, the species known for their allergic potential, and also many species of Penicillium and Aspergillus were detected, which is in concordance with other reports [3]. Moreover, the species capable of producing mycotoxins were also isolated, these including S. chartarum, A. versicolor, A. flavus, A. ochraceus, A. niger, P. expansum.…”

“…Penicillium, Aspergillus, Mucor, Rhizopus, Aureobasidium, Stachybotrys, and Cladosporium are the most common species found in the indoor environment [2][3][4]. Increased air-irborne fungal spore concentration is often associated with musty odor, water intrusion, high indoor humidity, limited ventilation, and failure to remove indoor mould growth.…”

Atopic dermatitis and respiratory symptoms in Russian and northern Norwegian school children: a comparison study in two arctic areas and the impact of environmental factors

“…keeping pets outdoors or indoors). Furthermore, modern buildings with poor ventilation, which is reported in 60% of the homes in Sør‐Varanger, tend to concentrate allergens indoors and thus elicit atopic symptoms 7,8 , 21,22 . Floors with carpets, which may be contaminated with high levels of domestic mite, animal dander, local pollens and mould, etc., were four times more prevalent in Nikel and was found to be a significant risk factor in eliciting AR in Nikel compared with Sør‐Varanger 8,23 .…”

Aspergillus species in indoor environments and their possible occupational and public health hazards

“…Prolonged exposure to fungi might result in rhino chronic symptoms that are not principally allergic but cause irritation [66, 67]. …”