FREETOWN, Sierra Leone (AP) — Sierra Leone's president said Tuesday that health workers found "many sick people and corpses" during a three-day lockdown of the country, which is battling an unprecedented Ebola outbreak.

The Friday-through-Sunday lockdown — believed to be the most dramatic disease-control measure taken since the plague was sweeping Europe in the Middle Ages — was so successful that a second one is being considered to slow Ebola's spread, President Ernest Bai Koroma said.

The Ebola outbreak is believed to have sickened more than 5,800 people and killed more than 2,800 in West Africa, primarily Liberia, Sierra Leone and Guinea. The World Health Organization has warned that these figures are likely underestimates. The unprecedented size and sweep of the outbreak has led to dramatic measures, like the cordoning off of entire communities in Liberia and the shutdown in Sierra Leone.

Koroma said on the radio that he is "mainly satisfied with the whole process, as it has helped reaching more homes and bringing to the fore many sick people and corpses."

Authorities are expected to give tallies later Tuesday on the results of the three-day lockdown. Koroma said it would be up to the task force coordinating the Ebola response to recommend another lockdown, and, if it did, he would consider repeating the exercise.

Many experts initially raised doubts about its ability to slow the outbreak, saying it would be hard to enforce, and there were fears it could breed resentment among the population and even lead to violence.

But in the wake of a largely successful lockdown, Dr. David Heymann, an Ebola expert, said reaching so many people with information about Ebola could be crucial to stopping the outbreak. Six months into the world's largest-ever Ebola outbreak, confusion, fear and misunderstanding about the disease is still stymieing efforts to control it.

"It's important for African governments to innovate and find new ways of getting messages out to the people," said Heymann, professor of infectious diseases at London School of Hygiene and Tropical Medicine. "(The lockdown) seemed to pass without violence and it went against much of international advice. Maybe it's the innovation that will make a difference."

In a sign of how much mistrust and misunderstanding still reigns, teams that were going door-to-door in Sierra Leone reported hearing rumors that the soap they were handing out was poisonous. People sent to treat patients, disinfect homes or provide information about Ebola have come under attack in some communities because of fears they are spreading the disease. One such team was killed last week in Guinea by villagers.

If more isn't done to control the outbreak, the case toll could hit 21,000 in the next six weeks, WHO predicted in a study published Tuesday. The U.S. Centers for Disease Control and Prevention also released its own, more dire predictions Tuesday, based partly on the assumption that Ebola cases are being underreported. The report says there could be up to 21,000 reported and unreported cases in Liberia and Sierra Leone alone by the end of this month and that cases could balloon to as many as 1.4 million by mid-January.

Experts caution that predictions don't take into account response efforts. In recent weeks, many countries have promised to set up new treatment clinics and send in doctors and nurses. Britain will train 164 health care workers to treat Ebola patients in Sierra Leone, the country's chief medical officer, Dr. Sally Davies, said Tuesday. Those being trained are members of the government's health staff and responded to a call for volunteers sent out last week.

Ebola, which is transmitted through bodily fluids, has no licensed treatment or vaccine. But some experimental drugs have been tried out in this outbreak. There are now plans for more organized trials in West Africa, possibly as soon as November.

Dr. Peter Horby, of Oxford University who is heading the effort, said he and colleagues will start assessing which clinics in the region might be able to conduct the trials. Horby said they are hoping to enroll 100 to 200 patients once they decide which treatment to test.

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Cheng reported from London. AP medical writer Mike Stobbe in New York contributed to this report.