The Nordic Expert Group for Criteria Documentation of Health Risks from Chemicals : 139. Fungal Spores
Year: 2006
Type: report
Abstract: Fungal spores are ubiquitous in the environment. Exposure levels in workplaces\nwhere mouldy materials are handled are much higher than in common indoor and\noutdoor environments. Febrile attacks of organic dust toxic syndrome (ODTS) and\nhypersensitivity pneumonitis may occur after episodes with excessive exposure.\nIn common indoor environments irritation symptoms have been ascribed to fungi\nat much lower exposure levels, especially in damp buildings.\nThe specificity of the response to fungi in hypersensitivity pneumonitis and\nasthma patients has been clearly demonstrated by bronchial provocation with the\nsuspected organisms. In vitro and animal studies have further shown differences\nin the inflammatory potential of fungal species. In animal studies, non-allergic\nresponses dominated after a single spore dose but allergic responses, especially to\nviable spores, were also observed. Repeated exposures induced both non-allergic\nand allergic pulmonary inflammation.\nTwo human challenge studies with whole spores provide information on effect\nlevels. A single dose study of subjects with sick building syndrome indicated no\nobserved effect levels (NOELs) of 4*103 spores/m3 for Trichoderma harzianum\nand 8*103 spores/m3 for Penicillium chrysogenum. The investigated effects were\nlung function impairment, mucosal and systemic symptoms and inflammatory\ncells in the blood. A study of asthmatic patients allergic to Penicillium sp. or\nAlternaria alternata showed lowest observed effect levels (LOELs) for reduced\nairway conductance of 1*104 and 2*104 spores/m3, respectively.\nIn epidemiological studies of highly exposed populations lung function decline,\nrespiratory symptoms and airway inflammation began to appear at exposure levels\nof 105 spores/m3. LOELs of 1*105-4*105 spores/m3 have been reported in wood\nworkers predominantly exposed to fungal spores and wood dust. The only welldesigned\nstudy on populations exposed to common indoor air indicates a NOEL\nof 7*102 spores/m3. The investigated effects were inflammatory markers in nasal\nlavage, and eye, throat, lower airways and non-specific symptoms. Fungal species\nwere seldom identified in the epidemiological studies.\nIn conclusion, the combined evidence from human challenge and epidemiological\nstudies support fairly consistent LOELs of approximately 105 spores/m3 for\ndiverse fungal species in non-sensitised populations. However, identification of\nthe fungal biota is required in order to document the occurrence of the more toxic\nmycotoxin containing species and pathogenic species before measurements are\nevaluated.\nFurther epidemiological studies of allergic responses to fungal spores and\neffects of pathogenic and mycotoxin containing species are recommended.\nKeywords: actinomycetes, fungal spores, hypersensitivity pneumonitis, irritation,\noccupational exposure limit, organic dust toxic syndrome, review, toxicity
Author: Wijnand Eduard
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
Funder: Nordisk Ministerråd
OpenAlex ID: W2119936271