To the Editor.
—The article by Dr Patz and colleagues1 suggests a link between outbreaks of cholera and marine algal blooms. We believe such a link is speculative in the extreme. Cockburn and Cassanos2 first suggested that seasonal fluctuations in cholera were associated with growths of bluegreen algae in freshwater ponds. Oppenheimer et al3 postulated that Vibrio cholerae was retained within the mucous sheath of the alga, was released into the water, and multiplied vigorously in the rich nutrients derived from the decayed bloom. The pond water was then used by humans, and cholera spread. Yet these authors performed no statistical analyses. The data presented showed that the number of cholera cases increased from just above zero in July and August to a peak of more than 700 between October and November, while the water temperature decreased from 32°C to 20°C. The peak algal bloom was 290
Gray JS, Depledge M, Knap A. Global Climate Controversy. JAMA. 1996;276(5):372-373. doi:10.1001/jama.1996.03540050032016