Fungal infections present a new challenge to infection-control personn
el. The investigation of recent outbreaks of candidiasis and aspergill
osis suggests that the epidemiology of these infections is more compli
cated than previously thought. The application of more discriminatory
genetic-typing systems to the study of outbreak strains has helped in
this process. Evidence for both endogenous and exogenous acquisition o
f fungal pathogens requires preventive strategies that incorporate bot
h chemoprophylaxis and standard infection-control practices such as ha
nd-washing. The role of sophisticated and expensive air-handling syste
ms on transplant units needs a critical reappraisal.