This map shows the places in the world where the next deadly virus will probably begin its fatal sweep across the globe. Red areas are plague "hot spots," and green areas are regions where epidemics are least likely to break out. An international team of scientists came up with the map after years of exhaustive research into virus patterns. Researchers discovered that disease disasters have quadrupled over the past 50 years, and they have evidence showing which groups are most likely to spread a virulent disease.
Wild animals are the most likely bearers of the next plague — 60% of epidemics are from "zoonoses," diseases that jump from animals to humans living in close proximity. The more that human populations spread into previously-uninhabited areas, the more likely we are to rub up against some viruses that the local fauna are resistant to, while we are not.
According to the Earth Institute at Columbia University:
In the new study, researchers from four institutions analyzed 335 emerging diseases from 1940 to 2004, then converted the results into maps correlated with human population density, population changes, latitude, rainfall and wildlife biodiversity. They showed that disease emergences have roughly quadrupled over the past 50 years. Some 60% of the diseases traveled from animals to humans (such diseases are called zoonoses) and the majority of those came from wild creatures. With data corrected for lesser surveillance done in poorer countries, "hot spots" jump out in areas spanning sub-Saharan Africa, India and China; smaller spots appear in Europe, and North and South America.
"We are crowding wildlife into ever-smaller areas, and human population is increasing," said coauthor Marc Levy, a global-change expert at the Center for International Earth Science Information Network (CIESIN), an affiliate of Columbia University's Earth Institute. "The meeting of these two things is a recipe for something crossing over." The main sources are mammals. Some pathogens may be picked up by hunting or accidental contact; others, such as Malaysia's Nipah virus, go from wildlife to livestock, then to people. Humans have evolved no resistance to zoonoses, so the diseases can be extraordinarily lethal.
Image via Nature.
Scientists Make First Map of Emerging Disease Hotspots [Earth Institute]