Assessment of fungi aeroallergens in homes of asthmatic patients in Benin City, Nigeria

Abstract

Atopic individuals have a tendency to suffer from one or more allergic disorders, such as asthma, which development appears to involve the interplay between host factors and environmental exposures. The results of a study of the fungi flora in indoor air of bedrooms of asthmatic patients are discussed. Samples were taken from 104 bedrooms of houses (homes) of asthmatic patients who have been diagnosed clinically and who were attending the Ear, Nose and Throat (E.N.T) Clinic of the University of Benin, Benin City. For each home, a set of 5 sterile Petri-dishes containing sabouraud dextrose agar, malt extract agar amended with antibiotic mixture of streptomycin and penicillin were exposed for a period of 5-10 min. between 25^oC - 28^o C for 10 days. Fungi isolates were identified by standard methods. A total of 68 species, comprising of 7 fungal genera were isolated and identified in bedroom indoor air (cfu/m³). Fungi included Cladosporium herbarium, Aspergillus spp., Penicillium oxalicum, Mucor sp. and Alternaria alternata. In the houses of the asthmatic patients, Cladosporium herbarium had the highest percentage frequency of occurrence (29.69% ±2.01 %),followed by Aspergillus niger (20.31±1.2%).The least fungus was Alternaria alternata (1.56±1.12).Also, in the control group Cladosporium herbarium had the highest frequency of occurrence (34.8± 4.60 %) while the least was Helminthosporium sp.(1.4±1.1%) A.niger had the highest density of 10⁵ cfu/m³, followed by Penicillium oxalicum (10⁴ cfu/m³) in the asthmatic group. The least was also Alternaria alternata. The prevalence of these fungi in bedrooms is an indicator of the probable high level of allergens produced and released by these fungi and may be related to allergic symptoms observed in some inhabitants of these houses. Therefore procedures to reduce possible fungal allergens to as low as possible by way of regular cleaning of the home may be a feasible way to preventing continuous and regular fungal allergy.