Climate & Emerging Infectious Diseases Linked

The World Health Organization (WHO) warns that emerging or re-emerging infectious diseases now cause one-third of all deaths around the world, with developing countries at the greatest risk.  Scientists from the Institut de Recherche pour le Developpement (IRD; France) reveal a relationship over a 40-year period between climate change and epidemics of a disease emerging in Latin America: Buruli ulcer. Rising surface temperatures in the Pacific Ocean tend to increase the frequency of El Nino events, which especially affect Central and South America approximately every five to seven years, causing waves of droughts. Comparing changes in rainfall in the region with changes in the number of cases of Buruli ulcer recorded in French Guyana since 1969, the team observed the statistical correlation: the decrease in rainfall and runoff led to an increase in areas of residual stagnant water, where the bacteria responsible, Mycobacterium ulcerans, proliferates. Human exposure to this pathogen results from the greater access to swampy habitats for fishing, hunting, etc.). Warning that: “Long-term forecasting of rainfall trends further suggests the possibility of an upcoming outbreak of Buruli ulcer in French Guiana,” the study authors express concern that greater focus is needed to establish a set of environmental parameters and their interactions and implications for human health.