Nairobi, Kenya – The death toll from the latest Ebola outbreak in the Democratic Republic of Congo has surged above 1,309, an extraordinary rise of more than 40 percent in just five days, government figures show, as a leading public health consultant says the virus is “spreading like a wildfire”.

Updated data released by the government on Saturday showed that as of Thursday, the total number of confirmed cases, including deaths, had climbed to 2,973. This was a 27 percent rise from the figure last Saturday.

The unprecedented rate at which cases are increasing and deaths are mounting has made the DRC epidemic the fastest-spreading Ebola outbreak ever documented.

Compounding the danger, the virus spreading in the DRC is Bundibugyo, which is the rarest of the four variants of Ebola known to affect humans and currently has no approved vaccines or treatments.

Abdulsalami Nasidi, a public health consultant who helped establish the Africa Centres for Disease Control and Prevention (Africa CDC), the African Union’s public health agency, told Al Jazeera the lack of a proven vaccine meant the virus was “spreading like a wildfire.”

Nasidi said the epidemic was unfolding in an area of active hostilities, compounding the shortage of public health resources common to African governments confronting outbreaks.

Scientists are racing to find a way to slow the epidemic, and the University of Oxford’s Oxford Vaccine Group said a volunteer had received the first dose of a rapidly developed experimental vaccine on Friday.

“This is an important milestone for the trial, and marks the next phase in our multinational collaborative journey to develop a Bundibugyo ebolavirus vaccine,” said the Oxford team’s chief investigator, Katrina Pollock.

The largest and deadliest Ebola outbreak in history killed more than 11,000 people out of at least 28,000 cases between 2013 and 2016, primarily in West Africa across Guinea, Liberia and Sierra Leone.

That outbreak took about eight months to reach the first 1,000 deaths. The latest epidemic in the DRC has done so in less than 10 weeks.

“We must act now,” Africa CDC Director-General Jean Kaseya wrote in a post on X last week. “If we do not stop it today, this will become the worst outbreak the world has ever documented.”

Al Jazeera’s Alain Uaykani, reporting from the DRC city of Goma, said the government’s response had lacked coordination and urgency, leaving medical personnel overstretched and working in poor conditions.

He said the death toll among health workers continued to climb on Saturday, with a doctor and a health worker among the latest victims.

More than 100 health workers have been infected since the outbreak was declared in May, and around 35 have died, a toll compounded by shortages of protective equipment and, in some communities, hostility from residents who question whether the disease is real.

An increasing number of healthcare workers at several medical facilities in the northeastern province of Ituri, the epicentre of the outbreak, have gone on strike over unpaid wages and unsafe working conditions.

Last week, dozens of workers at Rwampara General Hospital near Bunia went on strike. The hospital operates a major Ebola treatment centre, parts of which were set ablaze in May by angry residents who also chased after health workers fleeing in trucks.

The latest strike began on Saturday at the Elikya Ebola Treatment Centre in the provincial capital of Bunia. Activities were largely paralysed as doctors, nurses and security staff stopped work.

Approximately 100 workers held a protest outside the centre, saying unpaid bonuses were undermining morale and disrupting patient care.

“We need to be paid, because in the meantime the disease is spreading at the treatment centre,” Martin Bolombi, one of the striking workers, told The Associated Press. “I’ve already had five people die who are still inside there. A solution must be found for us,”

WHO Director-General Tedros Adhanom Ghebreyesus has warned that the true number of cases could be more than double the official count, as insecurity continues to restrict access to affected communities.

Contact tracing now reaches roughly 80 percent of known contacts, he said, but response teams still cannot reach every village or deploy where they are needed most.

The United States and Canada have both restricted entry for travellers who have recently been in the DRC, measures that run counter to the WHO’s own guidance issued in May, when it declared the outbreak a global health emergency.

Tedros has called for a ceasefire in the conflict gripping eastern DRC, arguing that medical resources alone are not enough to tackle the crisis, and political action is needed to open up access for responders before the virus takes hold in provinces not yet affected.