"The level of severity of this Bundibugyo outbreak is unprecedented," said Jean Kaseya, director general of Africa CDC, in his weekly briefing on Thursday.
The organisation is set to "start some studies to understand if there was a mutation," he added.
Health authorities must now assume there are 4000 cases, Kaseya said, noting that the current figure of more than 3900 confirmed cases was from the previous day.
This makes the number more than eight times higher than over the same time frame during the 2014 Ebola outbreak in West Africa, the most severe on the continent to date.
The death toll during this period is more than six times higher, Kaseya said.
Ebola is a life-threatening disease.
The virus is transmitted through physical contact and, in particular, contact with bodily fluids.
The current outbreak of the Bundibugyo variant, for which there is no approved vaccine, is the biggest ever in the central African country.
A trial of a newly developed vaccine is under way.
In 2014 and 2015, more than 11,000 people died in an Ebola epidemic in West Africa.
About 2300 people died in the second-worst recorded outbreak, which took place from 2018 to 2020 in eastern DR Congo.
Meanwhile, DR Congolese health authorities on Thursday were monitoring passengers travelling on a boat stationed near Kinshasa after a passenger died with symptoms matching the Ebola virus.
The passenger had disembarked after getting sick in Pimu, in the province of Mongala, more than 1000km from Kinshasa, Kaseya said, adding that the capital has no confirmed Ebola case.
The boat had been travelling for nearly three weeks along the Congo River with nearly 200 passengers on board.
They have been tested for Ebola and are in quarantine while awaiting their results.
"We decided to do that even if some of them didn't have symptoms because we want to make sure that we don't miss anything," Kaseya added.
News of the passenger's death caused panic in Kinshasa, which is far from the eastern region hit by the outbreak.
with AP
