An Ebola outbreak in the Democratic Republic of Congo that has caused more than 80 deaths has a "very high lethality rate" and no vaccine or specific treatment, the country's health minister warned Saturday.

A total of 88 deaths and 336 suspected cases of the the highly contagious haemorrhagic fever have been reported, the Africa Centres for Disease Control and Prevention (CDC Africa) said in an update on Saturday.

Medical aid group Doctors Without Borders (MSF) said it was preparing a "large-scale response", calling the rapid spread of the outbreak "extremely concerning".

"The Bundibugyo strain has no vaccine, no specific treatment," DR Congo's Health Minister Samuel-Roger Kamba said Saturday.

"This strain has a very high lethality rate which can reach 50 percent."

The strain has also claimed one life in neighbouring Uganda, officials said Saturday, that of a Congolese national.

That correlated with an announcement late Friday by Uganda's health ministry, which said a 59-year-old man from DR Congo had died in Kampala after being admitted earlier in the week. His body was repatriated the same day. 

Tests showed the victim in Uganda was infected with the Bundibugyo strain of Ebola, first identified in 2007.

Vaccines are only available for the Zaire strain, which was identified in 1976 and has a higher fatality rate of 60-90 percent.

Health officials had confirmed the latest outbreak Friday in Ituri province in northeastern DR Congo, bordering Uganda and South Sudan, according to CDC Africa. 

Adding to concerns of spread are significant cross-border population movements in the region affected.

"We've been seeing people die for the past two weeks," said Isaac Nyakulinda, a local civil society representative contacted by AFP by phone.

"There is nowhere to isolate the sick. They are dying at home and their bodies are being handled by their family members."

According to Kamba, patient zero was a nurse who reported to a health facility in provincial capital Bunia on April 24, with symptoms suggesting Ebola.

Symptoms of the disease include fever, haemorrhaging and vomiting.

MSF said it was mobilising medical, logistical and support staff to help respond to the outbreak.

"The number of cases and deaths we are seeing in such a short timeframe, combined with the spread across several health zones and now across the border, is extremely concerning,” says Trish Newport, MSF Emergency Programme Manager.

High risk of spread

It is the 17th Ebola outbreak to hit DR Congo, and officials warned of a high risk of spread.

"It is a large outbreak," said Jay Bhattacharya, acting director of the US Centers for Disease Control and Prevention (CDC) on Friday.

The previous outbreak of Ebola -- which has killed some 15,000 people in Africa over the past 50 years, despite advances in vaccines and treatment -- was last August in the central region.

That episode killed at least 34 people, before being declared eradicated in December.

Nearly 2,300 people died in the deadliest outbreak in the DRC between 2018 and 2020.

Ebola, believed to have originated in bats, is a deadly viral disease spread through direct contact with bodily fluids. It can cause severe bleeding and organ failure.

According to the World Health Organization (WHO), outbreaks over the past half century have seen a mortality rate among those affected of between 25 percent and 90 percent.

The virus spreads from person to person through bodily fluids or exposure to the blood of an infected persons, who become contagious only once they display symptoms. The incubation period can last up to 21 days.

"Give the uncertainties and severity of the illness, there is concern about the scale of transmission in affected communities," the WHO said Friday as it prepared to airlift five tonnes of material including infection prevention gear from Kinshasa.

Large-scale transport of medical equipment is a challenge in DR Congo, a country of more than 100 million people which is four times the size of France but has poor communications infrastructure.