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Feature Emerging Diseases

Disease trackers

BMJ 2011; 343 doi: (Published 05 July 2011) Cite this as: BMJ 2011;343:d4117
  1. Ed Yong, freelance journalist
  1. 1London, UK
  1. edyong209{at}

Why do many of the world’s emerging diseases, including SARS and H5N1 bird flu, originate from the same corner of South East Asia? Ed Yong investigates what’s special about the area and the international efforts to stop these deadly diseases in their tracks before they go global

The Mekong basin is teeming with life. Giant fish and crocodiles patrol the water, while thousands of birds fly through the air. The area’s biodiversity is among the richest in the world, and it is becoming more crowded. The basin stretches across 795 000 km2 of land, shared between China, Burma (Myanmar), Vietnam, Thailand, Laos, and Cambodia. It is home to an estimated 60-70 million people, mostly farmers, and this number is expected to increase to 120 million by 2025. These residents, and their livestock, are slowly encroaching into areas inhabited by wild animals—a clash of species that is turning the Mekong into a time bomb of disease. Within this throng of humans and animals, emerging infections can find plenty of hosts and vectors, and viruses and parasites can jump the species barrier into humans.

There have already been worrying precedents. In 2003, the coronavirus that caused SARS (severe acute respiratory syndrome) spread from a neighbouring province in southern China to 37 countries in a matter of weeks, killing a tenth of the people it infected. The virus was a new threat that had jumped into humans from bats and civets. In the same year, H5N1 influenza also emerged from southern China, spreading from poultry to humans, causing high death rates and spreading across South East Asia. Just this year, Chinese scientists identified a new tick-borne virus called SFTSV (severe fever with thrombocytopenia syndrome bunyavirus) that causes high fever and multiple organ failure and has killed 36 people. Since 1980, a new human …

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