The current Ebola crisis in West Africa is on pace to sicken more people than all other previous outbreaks of the disease combined, the health official leading the U.S. response said Thursday.
The next few weeks will be critical, said Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, which is sending more workers into the affected countries to help.
''It will be a long and hard fight,'' Frieden told a congressional committee Thursday.
In his prepared testimony, he estimated it would take at least three to six months to end the outbreak, under what he called a best-case scenario.
Frieden said the outbreak, which began in March, is unprecedented in part because it's in a region of Africa that never has dealt with Ebola before and has particularly weak health systems. He said the outbreak's two main drivers are lack of infection control as both health workers and families care for the sick and risky burial practices.
More than 1,700 people have been sickened in the current outbreak, in Guinea, Liberia, Sierra Leone and Nigeria. Nearly 1,000 have died, according to the World Health Organization, or WHO.
On Thursday Frieden said there's no way to know exactly how accurate that count is, or whether some cases are going unreported.
''The data coming out is kind of a fog-of-war situation,'' he said.
A medical charity told the House Foreign Affairs subcommittee that the world was too slow to react to the crisis, until recent headlines about two American aid workers who became infected in Liberia and were flown to the U.S. for care.
''Ebola is out of control in West Africa, and we are starting to see panic now around the world,'' said Ken Isaacs, vice president at Samaritan's Purse.
The two American aid workers, who were flown to Emory University Hospital in Atlanta, ''seem to get a little better every day,'' Isaacs said.
Frieden didn't rule out the possibility that a traveler could arrive in the U.S. unknowingly infected with Ebola. But he said he is confident there will not be a large Ebola outbreak here. The CDC has put hospitals on alert for symptoms and to check whether people are recent travelers so that they can promptly isolate any suspected cases until proper testing can be done.
Frieden said it is possible to stop the outbreak in West Africa using tried-and-true public health measures: find