By Robert Cole
The author is a Reuters Breakingviews columnist. The opinions expressed are his own.
(Updates with current news on New York City doctor testing positive for Ebola and World Health Organization's expectations for a vaccine.)
(Corrects to say EI Sturdza is UK investment firm, not Swiss)
Commerzbank analyst Simon Quijano-Evans recently analysed credit ratings for emerging market countries and concluded that there is a strong tendency to "under-rate" emerging economies - that is they are generally rated lower than developed market "equals" that have similar profiles of debt, investment or reform. The reason, according to Quijano-Evans, is that ratings assessments tend to be "blurred by political risk which is difficult to quantify and is usually higher in the developing world compared with richer peers.
As world leaders gather this week for the annual International Monetary Fund and World Bank autumn meetings, Ebola will be top on the list of priorities. Apart from the human toll, the economic impact will be felt for at least a couple of years, said David Evans, senior economist of the World Bank’s Africa Division.
Almost 3,000 West Africans have died from the current outbreak of Ebola virus, and on Tuesday, the U.S. Centers for Disease Control and Prevention warned that by January between 550,000 and 1.4 million people could be infected if nothing is done.