A few weeks ago, scientists issued a dire warning about the Ebola epidemic in West Africa: If nothing changes, the world could have tens of thousands of cases in the coming months.
So how can we tell if things have started to change — if international aid is starting to work?
One way is to follow a chart published every few days by the World Health Organization. It shows the number of new cases detected in West Africa. And on Wednesday, the chart showed something we hadn't seen in months: a decline in cases reported in Liberia.
Starting at the end of September the line goes down by about 160 cases each week. Could this mean the situation is improving in Liberia?
"You look at that, and it looks great. It's encouraging," says Columbia University's Jeffrey Shaman, who uses computer models to forecast the epidemic's future. "Maybe there's a slowing, which would be a very, very good thing."
And Shaman says his models also show a similar trend. For about five or six weeks now, the epidemic in Liberia has been growing more slowly than his models predicted.
But Shaman is cautious.
"I wouldn't be jumping for joy though, OK," Shaman says. "And the reason is that there are delays in the reporting, and not all the cases are actually found."
In fact, the big dip in cases could actually be a bad sign, Shaman says. It could mean more people might be hiding sick family members or not getting help for them because they're afraid.
For instance, treatment centers in Monrovia have started reporting they have some empty beds, which is surprising. Usually they have to turn away patients.
Those empty beds could be a good sign — it could mean there are fewer cases. But it might mean, instead, that people are staying away from treatment centers.
Health officials have been tricked before by what looks like a big drop in cases. Earlier in the outbreak, reported cases plummeted to zero in Guinea for almost a month. And health officials thought the outbreak might be over. They started relaxing.
"The key issue that made us fail in the early stages [of this outbreak], and why we didn't stop this back in March, is we thought we were on top of this," says WHO's Ian Norton, who is in charge of getting medical aid to West Africa.
But this time there's reason to be a bit more optimistic: Some help has arrived in Liberia.
More sick people in Monrovia now have a place to go for treatment, Norton says. That means they have a better chance of surviving and also are less likely to spread the virus to family and friends.
"We just opened the first of the new WHO-built facilities in Monrovia," he says. "And we're about to, in two weeks or so, open [an additional] 400 beds in two sites.
"The local contractors who have been working with us there have been working three back-to-back shifts a day so they're working 24 per day on sites," Norton adds. "It's incredible."
The international effort is about 20 percent along the way of building all the new treatment centers across Liberia, he says. And simply building the clinics isn't enough — a massive number of people still need to be trained to work in them.
"When you do the math," Norton says, "we quickly get up into the 6,000 to 7,000 staff needed in Liberia alone."
So there's still a long way to go to get this epidemic under control. But at least at this moment, he says, there's a bit of hope.
STEVE INSKEEP, HOST:
A few weeks ago scientists from the World Health Organization warned that without a huge international effort, Ebola will infect far, far more people than it does now. To monitor that scenario, the WHO publishes a chart several times a week. NPR's Michaeleen Doucleff has been closely watching that chart and recently caught a glimpse of something unexpected.
MICHAELEEN DOUCLEFF, BYLINE: For three weeks in a row, this chart has been showing a steady decline in new cases in Liberia. Could this mean what I think it means? I decided to ask Jeffrey Shaman at Columbia University what he thinks. Shaman puts data from field reports into computer models to try and predict the epidemic's future.
So did you take a look at that WHO report?
JEFFREY SHAMAN: I have seen it. I've only skimmed portions of it but, why don't I pull it up in front of me on the screen as well?
DOUCLEFF: Oh, yeah, that would be great.
So like, we were looking at figure three...
SHAMAN: Yeah. Yeah so what you're looking at is the cases reported each week from Liberia and Monrovia, right?
DOUCLEFF: That's right. So starting at the end of September, the line goes down by about 160 cases.
SHAMAN: You look at that and it looks great, it's encouraging. Maybe there's a slowing, which would be a very, very good thing.
DOUCLEFF: And Shaman says his model shows something similar. But...
SHAMAN: I wouldn't be jumping for joy though, OK. And the reason is, that there are delays in reporting and not all the cases are actually found.
DOUCLEFF: And Shaman says the big dip in cases could actually be a bad sign. It could mean more people might be hiding sick family members, or not getting help for them because they're afraid.
For instance, treatment centers are also reporting they have some empty beds, which is kind of surprising. Usually they have to turn away patients. So those empty beds could be a good sign. It could mean there are fewer cases. Or, it could also mean people are staying away from treatment centers.
SHAMAN: It's not an effort to be a killjoy here, but it's something that we're constantly worried about.
DOUCLEFF: In fact, health officials have already been tricked by what looks like a big drop in cases. Early on in the outbreak, reported cases plummeted to zero in Guinea for almost a month.
Ian Norton with WHO says health officials thought the outbreak might be over. People weren't showing up at treatment centers, they had empty beds, health officials started relaxing.
IAN NORTON: This key issue that made us fail in the early phases and why we didn't stop this back in March, we thought we were on top of it.
DOUCLEFF: But Norton says this time around, there's a reason to be a bit more optimistic - some help has arrived in Liberia. Norton says many sick people now have a place to go for treatment in Monrovia, which means they're less likely to spread the virus to family and friends.
NORTON: We've just opened the first of the new WHO-built facilities in Monrovia and we are about to in the next two weeks or so open a further 400 beds in two sites.
DOUCLEFF: Oh so there's been quite a bit of progress in the last couple weeks?
NORTON: Oh, yes. The local contractors that are working with us there have been working three back to back shifts per day. So they're working 24 hours per day on the sites. It's incredible.
DOUCLEFF: Norton says the international effort is about 20 percent along the way of building all the treatment centers across Liberia and they still need to train a massive number of people to work in these clinics.
NORTON: When you do the math, we quickly get up into the six to 7,000 staff required, in Liberia alone.
DOUCLEFF: So there's still a long way to go to get this epidemic under control, but Norton says, at least for this moment, there's a bit of hope.
Michaeleen Doucleff, NPR News.
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