DAKAR, Senegal — The World Health Organization declared on Thursday the end to the deadliest Ebola outbreak on record, which killed and sickened tens of thousands of people in West Africa, even as it cautioned that more flare-ups of the
DAKAR, Senegal — The World Health Organization declared on Thursday the end to the deadliest Ebola outbreak on record, which killed and sickened tens of thousands of people in West Africa, even as it cautioned that more flare-ups of the disease were likely.
The announcement in Geneva came after a recent chain of cases in Liberia was snuffed out, marking the first time since the start of the epidemic two years ago that Guinea, Liberia and Sierra Leone — the three countries that were hardest hit by the virus — had reported zero cases for at least 42 days, or two incubation periods of the virus.
Margaret Chan, the director general of the WHO, hailed the “monumental achievement” in curbing the outbreak, which, the United Nations said, killed more than 11,300 people and infected more than 28,500. At the height of the outbreak, the bodies of victims piled up in the streets of towns and cities that were overwhelmed and ill equipped to cope with the scale and speed of transmission.
But in a statement released in Geneva, Chan added that “our work is not done, and vigilance is needed to prevent new outbreaks.”
The immediate threat stems from persistence of the virus in body fluids, notably in the semen of male survivors, up to a year after they are free of the disease and show no symptoms, said Rick Brennan, the WHO’s director of emergency risk management, in Geneva.
Ten flare-ups had been reported across the three countries in the past nine months, four of them in Liberia and three each in Guinea and Sierra Leone, “and we are anticipating more,” Brennan said.
The risk, although significant, was low, he said. The new cases had occurred on average 27 days apart, but there have been none since mid-November. Any risk diminishes over time, as survivors’ immune systems clear out the virus.
WHO officials said that the health authorities in the affected countries had put in surveillance and rapid response mechanisms for managing the risk, and that those measures had proved effective in containing the flare-ups.
“People of course want to return to a normal, but it’s a new normal,” said Peter Graaff, a WHO director who is in charge of Ebola response.
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