Drought conditions linked to unexpected rise in infectious diseases

New research published in the journal Trends in Ecology and Evolution suggests that increasing global drought conditions are contributing to the spread of certain infectious diseases, a phenomenon described as the “drought-disease paradox.”

While many water-borne pathogens and parasites require abundant water to thrive—leading to declines in diseases like malaria and schistosomiasis during dry periods—others, such as cholera, West Nile virus, and dengue, tend to increase when water levels drop.

Ecologists Tara Stewart Merrill of the Cary Institute of Ecosystem Studies and Pieter Johnson of the University of Colorado Boulder analyzed nearly 100 scientific studies across the animal kingdom to document these trends. The research highlights how extreme dryness, seen recently in regions ranging from the Colorado River in the United States to the Danube and Rhine rivers in Europe, can unexpectedly facilitate the boom of specific deadly infections.