President Barack Obama said Ebola is controllable and the U.S. and its allies are working to help overwhelmed public health systems in West Africa take the needed steps.
Asked about the experimental drug, Obama said all the information isn't in: "We've got to let the science guide us."
There is no proven treatment or vaccine for Ebola, which so far has infected more than 1,700 people and killed more than 930 in West Africa in what has become the worst outbreak of this viral hemorrhagic fever.
"How many times have we found magic therapies that ended up ... doing more harm than good?" cautioned University of Minnesota professor Michael Osterholm, who advises the U.S. government on infectious disease threats.
"Vaccine and drug treatment right now is not going to be the main way you bring this to a stop," he added.
Scientists stress that there's no way to tell if the experimental drug ZMapp really made a difference for two American aid workers infected while working in Liberia.
"We don't even know if it works," stressed Dr. Anthony Fauci of the National Institutes of Health, which helped fund research that led to the drug's development.
The drug is a cocktail of three antibodies engineered to recognize Ebola and bind to infected cells so that the immune system can kill them. People's immune systems make antibodies to fight off various diseases, and attempts to cull those antibodies from the blood of people who survive an illness, or from animals date back to the 19th century and early diphtheria treatment. Using modern techniques to fight Ebola, scientists culled antibodies from laboratory mice, Fauci said, and ZMapp's maker now grows the antibodies in tobacco plants and then purifies them.
Fauci said the manufacturer has told the government that it would take two to three months to produce even "a modest amount." So the NIH is exploring ways to ramp up production, necessary to attempt formal testing or to consider more so-called compassionate use.
"Everybody's trying to speed things up," said Fauci, director of NIH's National Institute of Allergy and Infectious Diseases.
To help improve diagnosis in affected countries, the Food and Drug Administration on Wednesday authorized emergency use of an experimental blood test to detect Ebola. Early symptoms fever, vomiting and diarrhea can be confused with other illnesses. The test was developed by the Defense Department, and is only for use in DOD-designated laboratories.
This week, the WHO is convening an emergency committee to determine if the outbreak warrants being declared a "public health emergency of international concern," meaning it poses significant risk to other countries and requires more of an international response.
The WHO said that particularly in Liberia, health officials face community resistance from residents who fear going to the hospital and secretly care for ill loved ones at home, thus exposing themselves. Ebola is transmitted only through direct contact with the blood and other bodily fluids of someone who is sick.
But health care workers have to recognize the virus, too. Authorities in Nigeria have acknowledged that they didn't immediately suspect Ebola in the first known patient to travel to that country.
"The bottom line with Ebola is we know how to stop it: traditional public health," said CDC's Frieden said Wednesday: Finding and isolating patients, finding and educating who's been in contact with them and strict hospital infection control.
"Do those things with meticulous care and Ebola goes away," he said.
Minnesota's Osterholm fears those tried-and-true methods could be overshadowed by misunderstanding about any availability of the experimental drug.
"If the Americans had this serum all the time, why didn't they send it to us Africans to help save lives?" said Winston Ojukutu Macauley, a social commentator in Sierra Leone.
But taking an experimental drug requires making sure the patients fully understand there's no proof it will help and it might even harm, said Osterholm, noting that 40 percent of Ebola patients are surviving. And would it be appropriate for the U.S. to offer a drug to people in developing countries that hasn't been tested on its own citizens?
That's among the things the WHO meeting could address. Even if enough doses were available for wider experimental use, "we need to find a way to do this in a fair manner so that we can live with ourselves when someone asks why this person got it and why not that person?" said Dr. Heinz Feldmann, NIAID's virology chief.
AP Medical Writers Maria Cheng reported from London and Mike Stobbe from New York. Associated Press writers Clarence Roy-Macaulay in Freetown, Sierra Leone, and Bashir Adigun in Abuja, Nigeria, contributed to this report.
Ebola gains toehold in Nigerian megacity
Abuja, Nigeria • Nigerian authorities rushed to obtain isolation tents Wednesday in anticipation of more Ebola infections as they disclosed five more cases of the virus and a death in Africa's most populous nation, where officials were racing to keep the disease confined to a small group of patients.
The five new Nigerian cases were all in Lagos, a megacity of 21 million people in a country already beset with poor health care infrastructure and widespread corruption, and all five were reported to have had direct contact with one infected man.
Meanwhile, the World Health Organization met to decide whether the crisis, the worst recorded outbreak of its kind, amounts to an international public health emergency. With 1,711 reported cases, at least 932 deaths in four countries have been blamed on the illness.
The declaration would be an acknowledgment that the situation is critical and could worsen without a fast global response.
The group did not immediately confirm the new cases reported in Nigeria. And Nigerian authorities did not release any details on the latest infections, except to say they all had come into direct contact with the sick man who arrived by plane in Lagos late last month.
The Associated Press