GENEVA, Switzerland (AFP) — The World Health Organization (WHO) warned Wednesday that the Ebola outbreak confirmed to have killed 61 people in central Africa had a “big head-start”, and said “blanket travel restrictions” were hindering the response.

The outbreak was declared on May 15 in northeastern Democratic Republic of Congo, but the virus is believed to have been spreading under the radar for some time beforehand.

“The outbreak had a big head-start and we’re still behind,” WHO Chief Tedros Adhanom Ghebreyesus told reporters at the UN health agency’s headquarters in Geneva, but voiced hope that “we’re catching up”.

To date, there have been 344 confirmed Ebola cases in the DR Congo in the ongoing outbreak, including 60 deaths, according to Congolese health authorities and the WHO, which also tally over 100 suspected cases of the disease.

Fifteen cases, including one death, have also been reported in neighbouring Uganda, according to the Ugandan Ministry of Health.

The DRC is one of the world’s poorest countries and has suffered decades of violent conflict in its restive east.

The first identified case in the outbreak was a nurse, who went to a health centre on April 24 in the city of Bunia, the capital of Ituri province.

But the epicentre of the outbreak is about 90 kilometres (56 miles) away, in Mongbwalu, which suggests the outbreak originated there and that the cases then spread.

Efforts are under way to determine how and when the outbreak began.

Tedros, who had just returned from a trip to DRC, where he travelled to the epicentre of the outbreak, stressed that there were many possible scenarios.

“It could be January, it could be February, March, April,” he said, stressing the need to complete a “proper investigation”.

“But I think the focus now should be on the response,” he said, highlighting that “the virus is ahead of us… we need to move faster”.

No vaccine or approved treatment is available for Bundibugyo, the rare strain of Ebola behind the current outbreak, and efforts to contain its spread rely mainly on preventative measures and early identification and treatment.

Most large Ebola outbreaks known in the past have been caused by the Zaire virus, the only one for which a vaccine is licenced.

Ebola, which is passed on through close contact and bodily fluids, has killed more than 15,000 people in Africa over the past 50 years.

The deadliest of the 16 previous outbreaks in the DRC claimed nearly 2,300 lives out of 3,500 cases between 2018 and 2020.

WHO has said the risk from the outbreak is “very high” at the national level, “high” at the regional level, and “low” at the global level.

Tedros stressed Wednesday that while the WHO recommends exit screening at airports, ports and border crossings in impacted countries to prevent the spread of the virus, broader restrictions were not helpful.

“Blanket travel restrictions imposed by some countries are disrupting supply chains and hindering the response,” he said.

“We ask countries that have imposed blanket travel restrictions to lift them.”