WHO Deputy Director-General of Emergency Preparedness and Response Peter Salama said the organisation was "preparing for the worst-case scenario". This outbreak started back in December, about 20 miles from Bikoro, in Equateur province.

At least two people have tested positive for the virus since and at least five others, including two nurses, have possibly been infected and are being monitored. Mr Salama said he hoped DR Congo authorities will approve the deployment of an experimental vaccine, but warned that the drug was not a magic bullet.

The WHO says neighbouring countries have been alerted about the outbreak but that the risk of the disease spreading was "moderate".