The rate of new Ebola infections in Liberia appears to be declining and could represent a genuine trend, the World Health Organization said Wednesday, but the epidemic is far from over.

The disease is still raging in parts of Sierra Leone and there is still a risk that the decline in Liberia won’t be sustained, Dr. Bruce Aylward, an assistant director-general for WHO, warned.

Several times during the outbreak officials have thought the disease’s spread was slowing, only to surge again later. Officials have often blamed those false lulls on cases hidden because people were too afraid to seek treatment, wanted to bury their relatives themselves or simply weren’t in contact with authorities.

But now there are some positive signs: There are empty beds in treatment centers in Liberia and the number of burials has declined. There may be as much as a 25 percent week-on-week reduction in cases in Liberia, Aylward said.

Throughout the Ebola outbreak, WHO has warned that its figures have been incomplete and the number of cases are likely vastly underreported. That is still a concern, Aylward said, but the trend nonetheless appears to be real.

“The epidemic (in Liberia) may be slowing down,” he said during a telephone press conference from Geneva. The slowdown could be attributable to a rapid increase in safe burials of Ebola victims, an uptick in the number of sick people being isolated and major public awareness campaigns on how to stop transmission.

So far, more than 13,700 people have been sickened in the outbreak, which has hit Liberia, Guinea and Sierra Leone hardest. That figure, released Wednesday by the World Health Organization, includes cases from earlier in the outbreak that were recently found in patient databases but had never been reported.

In yet another sign of the difficulty of providing real-time, accurate data, the WHO figures showed that Liberia’s total death toll dropped to around 2,400 deaths from the 2,700 reported a few days ago. Dan Epstein, a spokesman for the agency, said that was because laboratory investigations showed that cases previously thought to be Ebola were not.

In all, the disease is believed to have killed nearly 5,000 people.

Cautioning against reading too much into the decline in Liberia, Aylward said that any let-up in the response could allow the disease to surge again.

“Am I hopeful? I’m terrified the information will be misinterpreted and people would start to think, oh great, this is under control. That’s like saying your pet tiger is under control.”

Liberia’s Red Cross said Tuesday that teams collected 117 bodies last week from the county that includes Monrovia, down from the high of 315 in one week in September, and the government reported last week that only about half of the available beds in treatment centers were occupied.

Others were more reluctant to call the decline a trend.

Ebola outbreaks come in waves, warned Benoit Carpentier, a spokesman for the International Federation of the Red Cross. Red Cross figures show deaths are still increasing outside Monrovia, he noted.

It’s possible that at least some of the decline is because cases are being hidden — a phenomenon that has plagued the response to the outbreak since the beginning, said Ella Watson-Stryker, a health promotion manager for Doctors Without Borders in Liberia.

She said her team has heard of people doing their own burials in order to avoid a government order that Ebola victims in Monrovia be cremated; the government has also cited fear of cremation, a practice deeply at odds with Liberian tradition, as a reason beds are empty in treatment centers. Watson-Stryker added that people may be staying away from such centers because they are still confused about what kind of care is given at them.

Aylward said the response must not relax.

“This hasn’t dropped off a cliff. … There’s a huge risk it wouldn’t be sustained,” said Aylward. “It would be a huge mistake … to think we can scale down the response.”

Instead, experts should redouble their efforts to track all of the people with whom the sick have come into contact — a task that has been nearly impossible in many parts of the outbreak because of the sheer number of infections.

There’s also tremendous work still to be done outside Liberia.

The western areas of Sierra Leone, near the capital, have seen a particularly steady increase in cases lately.

On Wednesday, the government numbers showed 10 new confirmed cases reported in the country’s western districts, which include Freetown, during the previous 24 hours. Recent days have seen those districts report more than two dozen new confirmed cases in a single day.

“We are in a crisis situation, which is going to get worse,” said Palo Conteh, the newly appointed head of Sierra Leone’s national Ebola Response Center. “Ebola is right ahead of us and it is running fast.”

He urged areas of the country experiencing increases in cases to follow the example of areas where the disease’s spread is declining: avoid contact with the sick, bury the dead properly and seek quick treatment for fevers.

The top U.N. official on Ebola, Anthony Banbury said Wednesday that the tremendous international response was beginning to pay off.

But Samantha Power, the American ambassador to the U.N., called on countries — especially those that had promised aid but not yet delivered — to do more. WHO said Wednesday it had received about half of the $260 million it needs to meet its objectives, and more had been pledged, leaving a gap of about 35 percent.

Met with government of #Ghana to discuss its own #Ebola prevention efforts — zero cases — and to offer the US’ thanks for hosting @UNMEER.

— Samantha Power (@AmbassadorPower) October 30, 2014

“The U.S. is not running away from Ebola but walking toward the burning building,” she said, as she urged others to do the same. Power spoke alongside Banbury in Ghana, where the U.N. mission on Ebola has its headquarters.

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