Ebola may have been spreading undetected for three weeks as death toll climbs to 88

A burgeoning new Ebola outbreak may have already been spreading for more than three weeks and poses a high risk to nearby African countries, experts say.

Public health experts used an urgent press conference a day after the outbreak was announced to warn there had already been 88 suspected virus deaths from 336 likely cases.

The virus spreading in a border area of the Democratic Republic of Congo (DRC) has also been identified as the rare Bundibugyo strain, which has no vaccine.

Epidemiologists have expressed concern that the outbreak of the highly contagious haemorrhagic fever seemed to have flared up so quickly in an area with busy cross-border traffic and migration.

Dr Jean Kaseya, director-general of the Africa Centres for Disease Control and Prevention, said officials had yet to identify the first case, but early investigation suggested it was in the third week of April.

He said: “So far we don’t know the index case. It means we don’t know the magnitude of this outbreak.”

All but one of the cases so far have been in DRC with the outbreak mainly in the gold-mining towns of Mongwalu and Rwampara of Ituri province, bordering Uganda.

A single case has been confirmed in Uganda, which health officials there said had been imported.

The location in a cross-border trade hub where large numbers of people were also fleeing insecurity meant a risk of spread to Uganda and South Sudan, Kaseya said.

He added: “The risk is huge to see this outbreak spreading also in other areas. For now, we are still talking about moderate for the continent, but high for the region. When we talk about the region, we talk mostly about Eastern Africa.”

He said there was no vaccine for the strain, unlike the more common Zaire strain, though he said there were candidates in early trials.

This is Congo’s 17th Ebola outbreak since the virus first emerged in the country in 1976. The country has spent decades trying to build surveillance networks to spot and beat outbreaks.

Dr Menelas Nkeshimana, an expert at Rwanda’s Ministry of Health, told the Telegraph: “It is very concerning to simultaneously see an Ebola outbreak in the DRC alongside an imported case reported in Uganda”.

“Situations like this naturally raise questions about the robustness of epidemic intelligence and response systems, because ideally such outbreaks should be detected and contained much earlier before significant mortality occurs and before international spread is observed.”

Dr Jason Kindrachuk, an associate professor of medical microbiology and infectious diseases at the University of Manitoba, Canada, added: “This is a very difficult situation for a number of reasons. In terms of my concern, I’d say that my current level of concern is quite high.”