INTRODUCTION

• In 1924 Storm van Leeuwen from Holland suggested that inhaled fungal spores could cause asthma. To investigate this possibility the allergy department of St. Mary's Hospital, Paddington, London obtained fungal cultures which they intended to grow so that they could assess the effects and possibly test patients. Two seasonal and three non-seasonal fungi were cultured. One of these was the mould Penicillium. Directly above the allergy laboratory was Fleming's laboratory. The bacteriological plate containing Staphylococci was contaminated by Penicillium which may very well have originated in the allergy department downstairs. Therefore it can be said that it was the allergists interest in fungal spores that resulted in the dawning of the antibiotic age, (Frankland, 1996).

• Although most fungi have periods of the year when their spores are more prevalent than others, some can be found virtually all year round. It is not uncommon for spore counts to exceed 4,000 per cubic metre with Cladosporium exceeding 2,000 and Alternaria 1,000. Understanding the aerobiology of fungal spores can produce a significant contribution to the understanding and treatment of human atopy. Types of fungi known to be allergenic include many fungi imperfecti such as Aspergillus, Penicillium, Cladosporium and Alternaria, (Anderson, 1985) and the allergic responses are generally due to the inhalation of spores rather than mycelia-derived material, (Salvaggio and Aukrust, 1981, Meyer et al., 1983). Although less is known about the allergenicity of basidomycetes than for the fungi imperfecti group, they were first reported to cause respiratory symptoms in 1951, (Davis et al., 1988). Allergic responses to each spore type differ between individuals and myco-allergens vary in the severity of the allergic reaction they induce. More people are allergic to Alternaria, than Cladosporium for example. Alternaria also produces more strongly positive reactions, while Cladosporium generally only produces a mild allergic reaction, (Cosentino et al., 1995). Cladosporium and in particular Cladosporium herbarum, are often the major contributor to air-spora and due to their high concentrations are therefore a major cause of inhalant allergy and allergic asthma in humans, (Vijal et al., 1991).

• Holdaway, (1993) states that the number of atopic individuals, as measured by skin prick tests, has not increased significantly in the last ten years. However, asthma is increasing in children and there is evidence to suggest that there has been an increase in the number of atopic individuals who develop asthma, (Woolcock, et al., 1995). The numbers of asthmatics who are sensitive to fungal spores also appears to be increasing. In Hungary, for example, the number has increased from 10.6% in 1977 to 38.5% by 1987/88, although this may be partly due to increased potency of the extracts used in skin-prick testing.

ASSESSING THE EFFECT OF FUNGAL SPORES

• Many types of fungal spore are known to be allergenic and these tend to come from the fungi imperfecti group. Assessing fungal spore allergy in patients is not easy for several reasons. Firstly, the number of allergens of for many spores including Alternaria have not been determined, (Budd, 1986). Secondly, there are standardized skin-prick tests for only a limited number of fungal spore types. Production of skin-prick test preparations relies on producing large amounts of spores from which the extracts can be made. However, the majority of basidiomycetes and many ascomycetes will not grow on standard laboratory media, (Salvaggio and Aukrust, 1981). Extracts from the fungi imperfecti group make up the majority of standardized skin-prick test extracts, because fungi imperfecti can be cultured. Difficulties in producing sufficient quantities of spore extracts for the other groups of fungi, such as basidiomycetes and ascomycetes, mean that although it is quite likely that many species of fungi within these groups may be allergenic it is difficult, at present, to prove it.

SITE INDEX

Home
Introduction
Fungi Imperfecti/Deuteromycota
Ascomycota
Basidiomycota
Fungal Spores and Allergy
Assessing the Effects
Sampling Spores
Culturing
Visual Identification
Details and Images of some common spore types

References
Links