El Niño Increases Diarrheal Disease Incidence by 200 Percent

The El Niño phenomenon--the warming of the equatorial Pacific ocean that occurs every two to seven years--has been linked to outbreaks of dengue, malaria, and cholera. Now, researchers from the Johns Hopkins School of Public Health, A.B. Prisma, and the Instituto Nacional de Salud in Lima, Peru, have found that the 1997-1998 El Niño season increased hospitalizations for diarrheal disease by 200 percent, according to a study published in the February 5th issue of The Lancet. The results are cause for concern, said the researchers, since diarrhea already causes one billion episodes and three million deaths annually in children under five worldwide.

The researchers estimate that hospital admissions due to diarrheal disease increased by more than eight percent with every one degree centigrade rise in temperature-results that will potentially increase diarrheal disease cases by millions worldwide with each degree of increase in ambient temperature due to global warming or other local factors.

A team of scientists lead by William Checkley, a PhD candidate at the Johns Hopkins School of Public Health, examined diarrheal disease hospital records for over 57,000 children from 1993 to 1998 and found that admissions during the El Niño season increased significantly above expected norms. The admissions increase was particularly sharp during Peru's winter months (May - November).

Experts in El Niño and human health include:

• William Checkley (graduate student, Public Health, Johns Hopkins School of Public Health)
• Jonathan Patz, MD MPH (assistant professor, Department of Environmental Health Sciences, Johns Hopkins School of Public Health)
• Robert Gilman, MD (professor, Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Professor, Department of Medicine, Johns Hopkins School of Medicine, A.B. Prisma)

This study was funded through USAID.

Further information will be available on the Child Health Research Project website http://ih.jhsph.edu/chr/chr.htm as of February 3.