686 TANSEY AND FLIERMANS 



D. gallopaua was isolated only from thermal sites. The lowest water 

 temperature directly associated with occurrence of D. gallopaua was 

 44°C. Samples from cooler sites did not yield this fungus, with one 

 apparent exception; D. gallopaua was isolated from water edges of 

 Four Mile Creek at a time when water temperature at this site was 

 27°C. This was a temporary condition since water at this site is 

 higher than 50°C most of the time. In three instances D. gallopaua 

 was isolated from foam collected on waters that were cooler than 

 44°C (Table 2), but in each case there was an immediate source 

 having a much higher temperature. The artificial stream received 

 water that had been heated to a higher temperature before mixing 

 with cooler water, and the 42.5°C site on Pond C and the 32. 5° C site 

 on Par Pond received current-borne foam formed a few minutes 

 earlier at hotter water— soil interfaces. 



Quantitative plating of impingement liquid from 15 air samples 

 yielded five CFU's of Phanerochaete chrysosporium and one each of 

 Rhizopus rhizopodiformis, Thielauia terrestris, and D. gallopaua. 

 Membrane filters from 17 air samples yielded 22 CFU's of A. 

 fumigatus, eight of P. chrysosporium, and one each of Thielauia 

 terricola, R. rhizopodiformis, and Melanocarpus albomyces. 



Several isolates obtained in this study are believed to represent 

 new species and are not included in the tables; they will be described 

 elsewhere. In no case did these new organisms form many CFU's on 

 assay plates. 



DISCUSSION 



The following species isolated in this study are zoopathogens: A. 

 fumigatus, A. niger, D. gallopaua, Emericella (Aspergillus) nidulans, 

 Thermoascus crustaceus, Mucor pusillus, M. miehei, R. nigricans, and 

 R. rhizopodiformis. There is a single report of disease caused by 

 Humicola lanuginosa, and Phanerochaete chrysosporium (as Sporo- 

 trichum pruinosum) caused very localized infections in injected 

 animals (Stretton, 1975). Most disease is initiated by inhalation of 

 spores of these fungi. In view of their relative significance (incidence 

 and severity) as causes of disease, A. fumigatus and D. gallopaua are 

 of greatest interest. 



Aspergillus fumigatus is a ubiquitous fungus that is pathogenic, 

 allergenic, and toxigenic. It is a frequent cause of disease of 

 humans and animals (Rippon, 1974; Emmons et al., 1977; 

 Jungerman and Schwartzman, 1972). An important feature of this 

 fungus in terms of our study is that a small amount of fungal biomass 

 can produce immense numbers of readily airborne spores. 



