May 2018 UPDATE.
What did WHO conclude?
At an emergency meeting, WHO experts said that "the conditions for a Public Health Emergency of International Concern (PHEIC) have not currently been met".
Had they decided otherwise, a larger response to the outbreak would have been triggered.
Media captionSome simple techniques can help prevent spread of Ebola.
Although Ebola had already spread to an urban area, the experts said they believed the outbreak could be brought under control.
They also stressed that it was "particularly important there should be no international travel or trade restrictions".
The WHO said it had identified more than 500 people who had potentially come into contact with Ebola patients in the country.
It said they would be closely monitored for symptoms of the disease and were likely to be among the first to be given an Ebola vaccine, which - although still in the experimental stage - proved effective during a trial.
The WHO said some health workers had become infected with Ebola.
WHO has previously admitted that it was too slow to respond to a deadly Ebola outbreak in West Africa from 2014-2016 that killed more than 11,000 people.
Life in the Ebola zone
One teacher in the region told the BBC's Newsday programme that people had stopped shaking hands when they greet. Ziko Ilema said: "I tried to greet a friend by shaking hands and he said: 'No, did you forget that Ebola is here?'"
"They forbid people to greet by using hands, eating animals from the forest, and people are now living with fear," he added.
Ebola is thought to be spread over long distances by fruit bats and is often transmitted to humans eating contaminated bushmeat - meat from wild animals such as monkeys or antelopes.
Bars, restaurants and offices in Mbandaka have started to provide soap and basins of water for people to wash their hands as a way to prevent the spread of the disease, according to the AFP news agency.
It also reports that officials are using infrared thermometers at the city's river ports to scan travellers in case they have a fever.
"But we don't have enough of the thermometers, so people are crowding up and getting annoyed," said Joseph Dangbele, an official at the private Menge port.
Health Minister Oly Ilunga has announced that all healthcare in the affected areas would be free.
What is being done to contain the outbreak?
WHO says that of the 45 Ebola cases reported, 14 are confirmed, 21 are probable, and 10 are suspected.
They were recorded in Congo's Equateur province. Mbandaka is the provincial capital.
Mr Salama said that isolation and rudimentary management facilities had been set up in the city.
He said the disease could have been taken there by people who attended the funeral of an Ebola victim in Bikoro, south of Mbandaka, before travelling to the city.
On Wednesday more than 4,000 doses of an experimental vaccine sent by the WHO arrived in Kinshasa with another batch expected soon.
These would be given as a priority to people in Mbandaka who had been in contact with those suspected of carrying the Ebola virus before people in any other affected area, Mr Salama said.
The vaccine, from pharmaceutical firm Merck, is unlicensed but was effective in limited trials during the West Africa outbreak.
However, it needs to be stored at a temperature of between -60 and -80 C, which is a challenge in DR Congo because electricity supplies are unreliable.
WHO said health workers had identified 430 people who may have had contact with the disease and were working to trace more than 4,000 contacts of Ebola patients who had spread across north-west DR Congo.
Many of these people were in remote areas, Mr Salama said.
Why does Ebola keep returning?
This is the ninth outbreak of Ebola in DR Congo - it was named after the country's Ebola river.
Ebola can be introduced into the human population through contact with the blood, organs or other bodily fluids of infected animals. These can include chimpanzees, gorillas, monkeys, antelope and porcupines.
It is not possible to eradicate all the animals who might be a host for Ebola. As long as humans come in contact with them, there is always a possibility that Ebola could return.
Ebola is make a huge comeback. The world’s hotspot for ebola is in the Congo. The number of active cases has skyrocketed but are grossly under-reported. The disease is highly contagious and it is a death sentence for 90% of all who contract the disease. Ebola grants the victim an agonizing death. With modern air travel beiing what it is, an emerging pandemic could result.