The new Ebola outbreak that has infected 111 people and killed 75 in the Democratic Republic of Congo since it began four weeks ago has the 'potential to be the worst ever seen'.
The agency that responds to humanitarian crises fears it will trump the pandemic of 2014, which killed 11,000 and decimated West Africa.
Virologists have repeatedly warned the situation is ‘hard to control’ because cases are in a conflict zone, roamed by armed Islamic militias.
And yesterday, Dr Tedros Adhanom, chief of the World Health Organization ramped up the warnings over its potential rapid spread.
The World Health Organization (WHO) reports the next seven to 10 days are critical in controlling the spread of the Ebola virus in the eastern Democratic Republic of Congo.
Its latest update reported 111 cases of Ebola, with 83 confirmed and 28 probable, including 75 deaths. The WHO reports it is continuing to rapidly scale-up its response to the Ebola outbreak in North Kivu and Ituri provinces, including in Oicha, a town difficult to reach because of security concerns.
More than 100 armed groups are operating in these areas, putting some places, known as Red Zones, off limits because of the dangers.
But, WHO spokesman Christian Lindmeier told VOA health workers have had access to all places they need to go with the help of MONUSCO, U.N. peacekeepers acting as escorts.
"Between Beni and Oicha there is a Red Zone," he said.
"Oicha, itself is not a Red Zone, but also getting to Oicha is possible with the help of MONUSCO, and we are very thankful for that."
Oicha is believed to be surrounded by Ugandan Islamist militias, who are blamed for a series of killings and abductions. Lindmeier said the next week is critical in efforts to prevent Ebola from spreading to areas that cannot be reached.
"The quicker we can respond and in which we can get to people, to talk to them about how to protect themselves, how to prevent infection, how to deal with infected family members and loved ones, the better it is for any future control," he said.
"So, the earlier we get to any place where this outbreak could possibly reach, the better."
The World Health Organization said 4,130 people have been vaccinated against Ebola, including 726 healthcare or frontline workers and more than 900 children.
It noted more than 7,000 additional doses of vaccine have been transported to Beni and more doses are in route to DRC from the United States.