permaculture

["L.J.L.D. Van Griensven" <mushex!vg@relay.nl.net>]

Compost spores and Health

For those interested in possible health effects of mold spores  
associated with composting operations and present in air:  We have  
done a study of the etiology of mushroom worker's lung with the  
following results.
The spores of the thermophilic actinomycetes Excellospora flexuosa,  
Thermomonospora alba, T. curvata and T. fusca  were collected from  
the air in compost-fermentation tunnels during the spawning of  
mushroom compost.  They were found present at over 10 power 9 CFU per

cubic meter of air. ( This is 10 times higher than needed for  
pathogenesis)
Aspergillus, Aureobasidium, Cladosporium, Penicillium and Scytalidium

were found at only 10 power 3 spores per cubic meter of air.  Sera of

10 mushroom growers with MWL were all found positive for one or more  
of the 4 actinomycetes by dot ELISA against spore antigens. No  
antibodies were found against Streptomyces vulgaris,  
Thermoactinomyces vulgaris, T. sacchari and Trichoderma viride.  Sera

of 11 of 14 workers engaged in handling  Phase 2 compost reacted  
positively with 1 or more of the actinomyces. Their serum titers  
increased with the duration of employment. The sera of 19 non-exposed

workers were negative. Results of inhalation provocation studies  
showed a causal relationship between spore exposition and disease.
The study was published in Mycopathologia 122: 21-28 (1993). Mushroom

compost is very much like any other compost and can therefore be  
considered as a model. 

Influence of spores coming from composting plants through the air to  
bone marrow transplant patients seems unlikely. Compost contains  
mostly thermophilic actinomycetes. After longer incubation at 45 C,  
thermophilic fungi will be found. A. fumigatus was never observed by  
us in mushroom compost.
Tunnels contain 100 tons of compost. Simple calculation shows the  
unlikeliness of  contamination by compost derived fungal spores  
through air. Besides, bone marrow patients are usually isolated in an

environment, that is made free of the microorganisms that are  
abundantly available in the air of hospitals.

Leo Van Griensven
Mushroom Experimental Station, Horst, The Netherlands.