Particle size of airborne Cryptococcus neoformans in a tower

Abstract

Nearly 106 cells of Cryptococcus neoformans were cultured per g of pigeon droppings in a vacant tower. The air in the tower contained an average of 45 viable cells of C. neoformans per 100 liters: 60% of the cells were less than 4.7 μm in diameter. It is estimated that a human exposed to this atmosphere for 1 h would have 41 cells of C. neoformans deposited in the lungs. Sweeping resulted in the aerosolization of large numbers of cells of C. neoformans from 4.7 to 11 μm in diameter, the number of cells <4.7 μm remained relatively constant. One minute after sweeping, 4.4% of viable airborne cells of C. neoformans were less than 1.1 μm in diameter. We believe that this is the first report of isolating such small cells of C. neoformans from a natural site.