CHAPTER III 

 MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 



Diseases Caused by Molds* and Yeasts 



The diseases produced by fungi in higher animals are mostly 

 localized infections of the skin (derma tomycoses), of the mouth and 

 throat (thrush), and of the lungs and air passages (pneumomycoses).. 

 In insects, one large series of forms, the Laboulbemales, produce local 

 affections only; many other forms from widely different groups are 

 destructive to particular insects. ' 



PNEUMOMYCOSIsf 



Aspergillosis. — The fungus disease of the lungs and air cells of 

 birds is quite uniformly attributed to Aspergillus fumigatus which is 

 widely distributed upon feed and grains as well. The agency of this 

 species in causing disease is well established. It grows best at blood- 

 heat. Inoculation experiments have reproduced t];ie disease. Iso- 

 lated cases are recorded where the same organism is regarded as the 

 cause of disease in horses or cattle and even man, but not proved; 

 Other species of Aspergillus, A. flavus, A. nidulans, A. niger, have 

 been listed among pathogenic forms from their presence at times in 

 diseased tissue. Whether these species are ever a primary cause of 

 disease is doubtful. 



Secondary Infections. — Spores of any species of fungus found in the 

 locality may find lodgment in wounds, orifices open to the outside, 

 such as the external ear or the air passages. Many of these spores 

 will germinate in such situations. If favored by dirt, pus, mucus, 

 or existing pathological condition the resulting growth in some species 

 develops into a secondary infection; most species lack entirely the power 

 to prpduce disease. The appearance of molds, especially species of 



• Arranged generically as far as possible. 

 t Prepared by Charles Thorn. 



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