New Study Reveals "Health Risk" Possibly Carried by Clouds

A team of Canadian and French researchers has revealed that "dark clouds on the horizon may be ominous not because they herald a storm, but because they carry drug-resistant bacteria over long distances." Lead author Florent Rossi stated in an interview with AFP, "We found that winds carry bacteria in the atmosphere, and they can travel long distances around the world at high altitudes in clouds." This discovery was published last month in the journal Science of The Total Environment. Researchers from Laval University in Quebec and Clermont Auvergne University in central France sought antibiotic-resistant genes from bacteria found in cloud samples. The samples were taken from an atmospheric research station located at an altitude of 1,465 meters (4,806 feet) above sea level on top of Puy de Dome, a dormant volcano in central France. Analysis of the retrieved fog revealed that it contained between 330 to more than 30,000 bacteria per milliliter of cloud water, with an average of about 8,000 bacteria per milliliter. The study did not provide any conclusions regarding the potential health effects of the spread of antibiotic-resistant bacteria in the atmosphere and estimated that only 5% to 50% of the organisms could be alive and likely active.