The link between environment and disease.

• Author: Lloyd, Jane
• Position: United Nations Environment Programme

"THERE IS A VERY, VERY BIG connection between the emergence of new diseases and environ-mental change", said Nick Nuttall spokesperson for the United Nations Environment Programme (UNEP). "We are only just starting to really fully understand it." Rapid changes to the ecosystems mainly due to deforestation and climate change could create "instability in the web of life, and this seems to favour pests", he told the UN Chronicle.

In the early 1990s, extensive deforestation in Malaysia, combined with forest fires in Sumatra, destroyed and eradicated large tracks of the natural habitat of fruit bats that carry the highly pathogenic Nipah virus. In search of food, these bats moved closer to human settlements, in backyard fruit trees, where the Nipah virus jumped from bats to pigs and then to people, Mr. Nuttall said.

Deforestation has been shown to affect the prevalence and creation of diseases. Since 1976, the World Health Organization (WHO) has noted the emergance of 30 new human diseases, as well as a resurgence and redistribution of existing ones. A recent study in Latin America found that a 1-percent rise in deforestation resulted in an 8-per-cent increase in malaria-carrying mosquitoes. As forest is cleared, it creates holes that when filled with water become breeding grounds for mosquitoes and other disease-carrying insects, Mr. Nuttall said. Deforestation also contributes towards climate change and creates conditions conducive to the transmission of malaria. This is most evident in mountainous areas in Africa, Asia and Latin America, according to Dr. Paul Epstein, Associate Director of the Center for Health and the Global Environment, at Harvard Medical School, in an interview with the UN Chronicle, adding that it puts an additional 10 per cent of the global population at risk of contracting malaria--"populations that weren't previously exposed".

As scientists look deeper into this phenomenon, they see a strong connection between extreme weather events and mosquito-borne diseases. In 2000, Mozambique was subjected to protracted flooding when it was hit by three cyclones, resulting in a "five-fold increase in malaria", said Dr. Epstein. In Kenya, environmental activist and 2004 Nobel Peace Prize Winner Wangari Mathaai found that the rise in the use of plastic bags could also be linked to incidences of malaria. Mr. Nuttall said that when littered plastic bags are filled with water, they become "a brand new habitat for mosquitoes that carry...