(Bloomberg) — The World Bank warned that the economic costs ofthe Ebola outbreak in West Africa will escalate to “catastrophic”proportions if the virus spreads, while Ghanaian President JohnDramani Mahama criticized the international response to thedisease.

“If other countries in the vicinity in the subregion of WestAfrica fail to do what Nigeria and Senegal have done — which is tokeep things under control — then the costs will become much muchlarger,” Francisco Ferreira, World Bank chief economist for Africa,said in a Sept. 19 interview in Lusaka, Zambia's capital.

The spread of the virus may cost Guinea, Liberia and SierraLeone, the three nations where most infections have taken place, asmuch as $809 million, the World Bank said on Sept. 17. Earlyfindings of the lender's research into the economic risks of thedisease spreading to other countries show the damage could be moresevere, he said.

Mahama said in an interview in New York yesterday that the Ebolaoutbreak may reduce gross domestic product in the region by about3.6%. Funds pledged by international donors haven't yet flowed inand a “panic response” by closing borders and airlines cancelingflights are further damaging the worst-hit economies, he said.

“These resources should be fast-tracked so that the countrieshave the resources to be able to fight the disease,” he said.

Aid Pledges

More than people have already died from Ebola in Liberia, SierraLeone and Guinea since the outbreak started in December and over5,000 have been infected with the disease, according to the WorldHealth Organization. The disease poses a threat to potential globalsecurity, U.S. President Barack Obama said on Sept. 16.

The outbreak will probably be contained within six to ninemonths, Mahama said. While the United Nations has estimated theregion needs $1 billion in funds to fight the disease, so farpledges have amounted to about $350 million, he said.

The economic costs of the outbreak are largely a result of fearand aversion behavior which spreads quickly once populations sensean outbreak might be out of control, Ferreira said. A World Bankreport on the topic will probably be presented at the lender'sannual meetings next month, he said.

“If that happens in a larger country like Nigeria or Senegalthen the costs would be much much higher,” he said.

Good Controls

Nigeria has a population of about 170 million and a grossdomestic product of $523 billion, while Senegal has 13 millionpeople and a $15 billion economy. By contrast the three mostaffected nations have a combined population of 21 million peopleand their economic output is $13 billion in total.

In Nigeria, eight people have died from the disease, while inSenegal there has been one case with the infected personrecovering.

Both Senegal and Nigeria, Africa's biggest oil producer, have sofar managed to control the spread of the disease through measuressuch as establishing adequate treatment centers that help quell the“panic factor,” Francisco said.

The World Bank approved a $105 million grant as part of its $200million commitment to help contain Ebola in Liberia, Sierra Leoneand Guinea, it said on Sept. 16.

“There is a very bad scenario lurking out there for which weshould be ready and which argues for very urgent action right now,”Ferreira said.