Did Deforestation Pave the Way for Ebola Outbreak?

Cutting down trees isn't just bad for the climate. It also can facilitate the spread of deadly diseases. Continue reading →

Deforestation is a huge global problem, because it destroys animal habitats, deprives indigenous peoples of their traditional livelihoods and contributes to climate change. But if that doesn't tip the scale for you, here's yet another downside to be concerned about. Deforestation might have a role in this year's outbreak of Ebola in West Africa, which already has killed 4,500 people there. The often-fatal disease now is raising anxiety in the United States, after two Dallas nurses caught Ebola while treating a Liberian refugee who eventually died.

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A 2005 article in the journal Emerging Infectious Diseases, researchers from Johns Hopkins University and the Consortium for Conservation Medicine points out that about 75 percent of infectious diseases - including Ebola - are caused by pathogens that started out in animals but then mutated and jumped to humans. Deforestation increases contact between humans and wildlife, who often expose themselves to diseases when they kill and eat the animals for food. When loggers build roads deep into forests to enable them to haul out timber, they also provide greater mobility for people with infections, who then can spread them far and wide.

A 2012 article in the Onderstepoort Journal of Veterinary Research notes that since the mid-1990s, Ebola outbreaks in Africa have closely tracked drastic changes in forest ecosystems. "Extensive deforestation and human activities in the depth of the forests may have promoted direct or indirect contact between humans and a natural reservoir of the virus," the researchers concluded.

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This year's outbreak in west Africa follows that template. A July Washington Post article reported that the three countries hit hardest by the epidemic also have experienced massive deforestation. In Guinea, the rainforest has shrunk to less than a fifth of its original size, and in Liberia, more than half of forests have been sold off to loggers. Sierra Leone has lost a quarter of its wooded land, according to the U.S. Forest Service.

Roads created by loggers allowed Ebola to spread from the forest to urban areas. Jonathan Epstein, a veterinarian and epidemiologist with EcoHealth Alliance, told Public Radio International: "This is certainly what happened as cases moved from the Guéckédou region of Guinea, into Conakry, the capital. That hadn't happened before."

A logging camp in Liberia

In this collection of compelling images from around the web, sea monkeys make waves, fall colors are seen from space and a deadly volcanic eruption covers a temple in ash. Check out these and other amazing aerial and satellite images from around the world. Above, a National Weather Service satellite image from Sept. 30 shows the temperature of Earth's surface as a cold front moving across the plains brought severe thunderstorms to areas in South Dakota and Nebraska.

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This aerial picture taken on Sept. 28, 2014 shows rescue workers and Self Defense Force soldiers searching for missing climbers and survivors among ash-covered cottages and a Shinto shrine (top) on the summit of Mount Ontake, one day after the volcano erupted in central Japan. Dozens of hikers were killed and hundreds were trapped at the popular tourist destination.

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An estimated 35,000 walruses gathered last week on an island near Point Lay, Alaska. The walruses, which reside in the Chukchi Sea, came ashore to rest, which they will do between dives for food. Walruses typically use sheets of floating ice as rest areas between swims, but such ice platforms melted away in mid-September.

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Data from the Landsat 8 Earth observation satellite provides a view of a phytoplankton bloom (green and blue swirls) near the Pribilof Islands off the coast of Alaska, in the Bering Sea. The turquoise waters are likely colored by a type of phytoplankton called coccolithophores.

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NASA’s Terra satellite captured these views of fall colors around the Great Lakes and New England.

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European satellite data shows that gravity has dipped in West Antarctica because of melting ice. The brownish areas in the graphic are places where the variation has been greatest.

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In this picture taken by NASA astronauts, fires are creating a pall of smoke over the Amazon rainforest. The tan areas along the top of the photo are already-deforested sections of the Brazilian state of Mato Grosso.

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At sunset, sea monkeys (brine shrimp, in white above) move en masse to the ocean surface, creating currents that have similar power to wind and tides, a new study reports. At sunset, the swim down away from predators, creating strong currents that affect circulation patterns around the world's oceans.

Tiny Sea Monkeys Create Giant Ocean Currents