Counterpoint: Invasive aspergillosis and the environment - Rethinking our approach to prevention

Preventive measures are important in the control of invasive aspergillosis (IA) because diagnosis is difficult and the outcome of treatment is poor. I f effective strategies are to be devised, it will be essential to have a cl earer understanding of the sources and routes of transmission of Aspergillu s species. Nosocomial outbreaks of IA highlight the fact that Aspergillus s pores are common in the hospital environment. However, in general, such out breaks are uncommon. Most cases of IA are sporadic in nature, and many of t hem are now being acquired outside of the hospital setting. Housing patient s in high-energy particulate air-filtered hospital rooms helps prevent IA, but it is feasible and cost-effective only for the highest-risk groups and for limited periods. Control measures, which are designed to protect patien ts from exposure to spores outside the hospital, are even more difficult. N evertheless, now that high-risk patients are spending more time outside of the hospital, the cost benefits of antifungal prophylaxis and other prevent ive measures require careful evaluation.