Ebola Lying in Wait

NEW YORK TIMES by Pam Belluck and William J. Broad     April 20, 2015

A growing body of scientific clues — some ambiguous, others substantive — suggests that the Ebola virus may have lurked in the West African rain forest for years, perhaps decades, before igniting the deadly epidemic that swept the region in the past year, taking more than 10,000 lives.

Around 2004 at a government hospital in Kenema, Sierra Leone, a team of American scientists and West African medical personnel found what appeared to be Ebola antibodies in nearly 9 percent of blood samples. Credit Carl De Souza/Agence France-Presse — Getty Images

Until recently, Ebola had been considered a threat mostly to Central African nations. Yet studies tell of possible Ebola antibodies in human blood samples drawn in West Africa long before the current outbreak. And genetic analysis suggests the West African virus broke off from a parent strain in Central Africa at least 10 years ago, possibly as long as 150 years ago.

“My gut feeling,” said Dr. Peter Piot, the director of the London School of Hygiene and Tropical Medicine, who helped discover the Ebola virus in 1976, is that the evidence points to “infection before the current epidemic.”

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And Stephen S. Morse, an infectious disease expert at the Mailman School of Public Health at Columbia University, said it now seemed likely that Ebola had long smoldered in the West African jungle.

Perhaps, he said, years of limited encounters between people and the virus had produced a relatively small number of human cases that were never identified and never spread: “None of the embers reached the stage of a fire.”

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http://www.nytimes.com/2015/04/21/health/ebola-lying-in-wait.html?_r=1