Monday March 29

Keynote Lecture

KL1

Thoughts on the origin of virulence of pathogenic fungi

Arturo Casadevall

Albert Einstein College of Medicine, USA

casadeva@aecom.yu.edu

Of the more than 1.5 million fungal species only about 150-300 are pathogenic for humans, and of these, only 10-15 are relatively common pathogens.  In contrast, fungi are major pathogens for plants and insects.  These facts pose several fundamental questions including the mechanisms responsible for the origin of virulence among the few pathogenic species and the high resistance of mammals to fungal diseases.  This talk will explore the origin of virulence among environmental fungi with no obvious requirement for animal association.  Dr. Casadevall will develop the hypothesis that interactions with non-animal hosts such as protista selected for traits that, in certain circumstances like weakened immunity, can allow invasion of mammalian hosts.  Furthermore, the presentation will discuss recent evidence that vertebrate endothermy and homeothermy create a restricted environment for the overwhelming majority of fungal species and speculate that pressures from fungal diseases contributed to both the extinctions at the end of the cretaceous that resulted in the demise of the dinosaurs and to the great mammalian radiation that followed in the tertiary era.   Finally, Dr. Casadevall will comment on the possibility that climate warming will erode the thermal difference between mammalian and environmental temperatures, an event that could potentially usher in new fungal diseases in the late 21^st century.