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Aspergillus fumigatus  

(from MycoAlbum CD by GLB)

This microscopic image of Aspergillus fumigatus shows the long stalks (conidiophores) that support the swollen head (vesicle) from which  the spore generating cells (phialides)  produce long chains of spores (phialospores or conidia).   This entire cluster of fruitbodies   is smaller than the dot at the end of this sentence. 

Aspergillus fumigatus likes high temperatures and its optimum temperature for growth is about 37C (blood temperature).   It is not surprising, therefore, that it is also known as a parasite of humans, other mammals and birds.  In humans it has been reported as a causal agent of aspergillosis of the eye. 

In birds it can be a serious a serious problem causing pulmonary infections of turkey poults.  It has been reported as the most serious cause of death in penguins and other birds in captivity in zoological gardens.    The birds are maintained well away from their natural environment which reduces their resistance to disease and makes them more prone to casual infections.   Again, the causal agent is a warm temperature organism and  much more common as a component of the air spora (bioaerosol) in the new environment.   This is especially true of zoos where there is always a lot of wet straw and other organic materials lying around and this is a favourite habitat for Aspergillus growth.

In nature A. fumigatus  is commonly associated with hay that has become wet and undergone heating.  Aspergillus fumigatus can grow at temperatures of 50C or higher.   It has caused pulmonary aspergillosis in old horses that have been fed poor quality hay.  

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