A World Bank official says the Ebola epidemic will not be as costly to West Africa's economy as previously feared, thanks to effective containment efforts.

Francisco Ferreira, the bank's chief economist for Africa, told an audience in Johannesburg Wednesday that he expects the epidemic’s economic toll on the region will range from $3 to $4 billion.

The World Bank in October had predicted the economic impact could be as high as $32 billion if the virus spread significantly outside the borders of Guinea, Liberia and Sierra Leone, the three countries hardest hit by the outbreak.

"The risk of the highest case of economic impact of Ebola has been reduced because of the success of containment in some countries," Ferreira said, according to the Reuters news agency. "It has not gone to zero because a great level of preparedness and focus is still needed."

Ferreira said efforts to keep the outbreak from spreading to other African countries were largely successful. Senegal and Nigeria reported cases of the disease but have since been declared Ebola-free. Mali is now seeking to contain a small outbreak.

The earlier, more dire prediction reflected worries that if Ebola were to spread more vigorously beyond the three countries at the outbreak's epicenter, it would devastate cross-border trade, supply chains and tourism, Reuters reported.

But the "fear factor" has spread well beyond the outbreak’s actual range, Ferreira said, noting it has deterred tourists from Kenya, South Africa and other countries otherwise unaffected by the contagion.

Ferreira said falling global oil prices, which have dropped by almost a third since June, also has fueled instability among African oil producers, Reuters reported. Nigeria is the continent’s largest exporter of crude oil.

The World Health Organization last week reported a slight rise in the Ebola death toll, saying there have been 5,177 deaths among 14,413 confirmed cases worldwide.