The researchers, at Harvard University and biotechnology firms Pulmatrix and Inamed, report results from their clinical study of 11 healthy males this week on the web site of the Proceedings of the National Academy of Sciences. Their work may help decrease the spread of bacteria and viruses responsible for airborne infectious diseases such as influenza, tuberculosis, and SARS.
"We found a sharp demarcation between individuals who are 'high' and 'low' producers of bioaerosols, small droplets of fluid exhaled from the lungs that may carry airborne pathogens," says lead author David A. Edwards, Gordon McKay Professor of the Practice of Biomedical Engineering in Harvard's Division of Engineering and Applied Sciences. "Roughly half our subjects exhaled tens of bioaerosol particles per liter, while the other half exhaled thousands of these particles. The number of exhaled particles varied dramatically over time and among subjects, ranging from a low of one particle per liter to a high of more than 10,000."
These results led Edwards and his co-authors to conclude that roughly half the population - 6 of 11 individuals in their study - may produce more than 98 percent of all potentially pathogenic bioaerosols.
The researchers found that a six-minute inhalation of aerosolized salt-water solution, often used in the treatment of asthma, can markedly reduce the number of bioaerosol particles exhaled by these "high-producers" for up to six hours. Using a cough machine designed to simulate normal human breathing, they linked the reduction in droplet exhalation after saline administration to increased surface tension among fluids lining human airways, producing
Contact: Steve Bradt