Indoor Spore Levels in Asthmatic and Control Homes

Abstract

RATIONALE: Indoor fungal spore exposure is often suspected to be an asthma trigger. To investigate the difference in indoor spore levels found in homes of asthmatics and non-asthmatics we conducted the following studies. METHODS: Homes (n=23) containing a minimum of 3 individuals with at least one asthmatic child and control homes (n=19) without an asthmatic child but with similar occupant characteristics otherwise were recruited. Control homes were from the same neighborhoods and were recruited by referral from the asthmatic homes. Airborne fungal collections were made in at least 4 areas of the home including the child's bedroom, living/family room, kitchen and basement. Corresponding outdoor collections were taken. Collections were made using an Allergenco MK-3 set to operate for 10 minutes at 15 L/M. Slides were mounted with Calberlas stain in glycerin jelly and counted microscopically at 1000x. Counts were displayed as grains/M3. RESULTS: Mean indoor spore counts were 7974 spores per cubic meter of air in asthmatic homes and 980 spores per cubic meter of air in control homes. The greatest difference in airborne spore levels was seen in basement collections (asthmatic mean = 27337; control mean = 1232). The smallest difference in airborne spore levels was in the child's bedroom collections (asthmatic mean = 1265; control mean = 828). Major spore types found in these homes included Cladosporium and Aspergillus/Penicillium. CONCLUSIONS: In the homes of this selected set of asthmatic children there were higher concentrations of indoor airborne fungal spores than in similar homes of non-asthmatic children from the same neighborhoods.