The Ebola outbreak that drew a large international assistance effort to the Democratic Republic of Congo may be coming under control, one of the Canadian experts involved in the response said Sunday.

In an interview from Mweka, Dr. Heinz Feldmann said a decision is expected in the next day or two about whether another wave of experts will be needed when the current team rotates out of the country on Oct. 11.

Feldmann, who is head of the special pathogens division of the National Microbiology Laboratory in Winnipeg, said a second team has been chosen and is getting ready to travel to Mweka in case the World Health Organization's Global Outbreak Alert and Response Network - which goes by the nickname GOARN - determines longer term international help is needed.

"We're just waiting for WHO and GOARN to either call it off or give the go-ahead," Feldmann said.

He and colleagues Allen Grolla and Dr. Gary Kobinger travelled to the town in the province of Kasai Occidental to set up a mobile laboratory that can operate in locations where few resources are available. The mobile lab was designed and built at the Winnipeg laboratory, part of the Public Health Agency of Canada.

It can be safely operated where other, more sophisticated lab setups cannot. For instance, the hospital where the Canadian team has established its base has electricity from 7 p.m. to 10 p.m. daily - if that. So the mobile lab must run off a generator.

By Sunday, the team had diagnosed four positive cases in five days of operation at Mweka. As of late last week, the ministry of health of the Democratic Republic of Congo announced 17 recent cases in Mweka and Luebo, where experts from the U.S. Centers for Disease Control have set up a laboratory.

"From the sample numbers and the positive cases it seems to be that we're looking towards the end of this," said Feldmann, a veteran of several Ebola and Marburg fever containment efforts.

"That's what it looks like but that has to be taken with caution, because one case could start a new transmission chain and it could all start over again."

The outbreak is believed to date back to late April and may have involved several hundred people. Current estimates suggest roughly 170 people have died and more than 200 others were ill with symptoms that may have been Ebola or diseases that can be confused with a non-fatal case of Ebola. (Ebola Zaire, the strain of the disease behind this outbreak, generally kills between 80 and 90 per cent of people infected with it.)

In the early stages of the disease, Ebola has symptoms shared by a number of other diseases common in this part of Africa. Some cases of shigellosis and typhoid fever have been diagnosed among the suspected Ebola sufferers.

"If you ask my personal opinion, the (estimated case) number is far too high. We are not having 400 and some Ebola cases here. But it is tough to say how many or what the exact number is," Feldmann said, who acknowledged it may never be clear how large this outbreak was.

There's no way to confirm infections in the people who died before the international teams arrived in September. And while looking for Ebola antibodies in the blood of the suspected cases who survived would determine whether they were actually infected, the chances of getting blood samples from most or even many of those people are remote.

It would require suspected survivors to walk perhaps several kilometres to a health centre to have blood drawn. And while Feldmann said there doesn't seem to be as high a level of cultural resistance to giving blood samples in this region as there is in other parts of Central Africa, people don't understand the need.

The alternative - taking those who want to draw blood to the survivors - is impractical given the dismal shape of roads in the region.

"We're limited in cars. We're limited in staff. So it's a very challenging task to go back to all these survivors," Feldmann said.