With those three West African nations - Sierra Leone, Guinea and Liberia - already seeing their economies crumble because of the disease, Lagarde emphasized: "We should very be very careful not to terrify the planet in respect of the whole of Africa."
"These three countries are severely hit. We are going to try to give them as much support as we can; the big urgency is to stop it, contain it."
"But it's not the whole of Africa," she stressed. "Businesses have to continue, the economies of all the others countries have to keep on working and creating jobs."
To underscore the message, Lagarde was wearing a large button on her lapel declaring "Isolate Ebola, Not Countries", which was given to her by Guinea's President Alpha Conde.
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The call came as the annual meetings of the International Monetary Fund and World Bank were wrapping up in Washington.
Ebola was singled out as a pressing threat during the meetings, and both institutions pressed the world for stronger, faster efforts to combat the disease.
The Ebola outbreak has killed more than 4,000 people in just a few months, nearly all in Guinea, Liberia and Sierra Leone.
Earlier in the day, Sierra Leone's finance minister Kaifala Marah said the epidemic was isolating the three hardest-hit countries, with devastating economic consequences.
"Everybody is running away from Ebola... By default or design, it really is an economic embargo," he said.
