As the first batch of over 4,000 Ebola vaccines arrived in Kinshasa there were warnings that the outbreak had spread to a major city.
So far all the 23 people believed to have died from the virus have been in isolated areas giving the authorities hope of being able to ring-fence it.
But now a case has been detected in the city of Mbandaka with a population of one million people.
It's the ninth time Ebola has been recorded in Democratic Republic of Congo since the disease made its first known appearance near its northern Ebola river in the 1970s.
It's the first time the newly arrived vaccine will have been used since it was developed two years ago
Ebola is most feared for the internal and external bleeding it can cause in victims owing to damage done to blood vessels.