JOHANNESBURG, 7 October 2009 (IRIN) - Cholera is not only linked to climate change, it also has an El Niño angle. For instance, Papua New Guinea, an island state in the Pacific Ocean, recorded its first cholera cases in 50 years in 2009, which also happens to be an El Niño year. The periodic flow of warm sea water across the surface of the central and eastern Pacific Ocean, called El Niño, can lead to higher atmospheric temperatures and heavy rains.
When these conditions are coupled with the rise in temperature and heavy rainfalls caused by climate change, ideal conditions are created for the bacterium that causes cholera to multiply, bringing about a global resurgence of the disease.
The Intergovernmental Panel for Climate Change (IPCC), an authoritative global scientific body, cited research in Bangladesh, led by distinguished US scientist Rita Colwell in the late 1990s, which established the link between the cholera bacterium, sea surface temperature and phytoplankton, microscopic plant-like organisms that live in the ocean.
Warmer surface temperatures increase the abundance of phytoplankton, which supports a large population of zooplankton - animal-like micro-organisms - which serves as a reservoir for cholera bacteria, a waterborne disease. Colwell and her colleagues also traced the source of the cholera bacterium to the plankton in rivers and estuaries. A World Health Organization (WHO) study found that during the 1997-98 El Niño, a rise in sea surface temperature coupled with excessive flooding emerged as two significant factors in cholera epidemics in Bangladesh, Djibouti, Somalia, Kenya, Tanzania, and Mozambique.
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