The death rate of the Ebola outbreak in the Democratic Republic of the Congo is between 30% and 50%, the World Health Organization has said, as its head arrived in the country to support efforts to contain the disease.

Anaïs Legand, from the WHO’s high threat pathogens team, said the revised death rate estimate is based on confirmed cases. “It’s huge. It means that up to five out of 10 people are likely to die,” Legand told reporters in Geneva.

She also said that a patient had recovered from Ebola and was discharged from a health centre in the DRC on 27 May after two negative tests, the first recovery to have been confirmed in the outbreak.

The WHO has recorded 10 confirmed and 223 suspected Ebola deaths in the DRC since the outbreak was declared on 15 May, among more than 1,000 confirmed and suspected cases.

Tedros Adhanom Ghebreyesus, the organisation’s director general, arrived in Kinshasa on Thursday and was due to travel to the centre of the outbreak, in the north-east Ituri province, on Friday, but the trip has been pushed back by a day.

“That thing can be stopped,” Tedros told reporters, adding that the WHO did not support travel bans because they “don’t help much”.

“Together, we will overcome this outbreak,” he said in a separate message to Congolese citizens, promising to do “everything in my power to help”.

The true scale of the outbreak may be significantly larger, the WHO said, because the virus is believed to have circulated undetected for some time.

The outbreak is the 17th recorded Ebola epidemic in the vast central African country, which has a population of more than 100 million. The disease was first identified there in 1976 and its death rate has averaged 50% across all outbreaks, according to the WHO.

Complicating relief efforts, the outbreak is centred on a mineral-rich region fought over by armed groups. “Conflict and displacement make everything harder,” Tedros said. “I am making a direct appeal to all warring parties in this region: please declare a ceasefire. No cause, no conflict, no grievance is worth condemning innocent people to death from a preventable disease.”

More than 245,000 people have fled eastern DRC to neighbouring countries since January 2025, according to the UN refugee agency. Armed groups operating in the area include the Rwanda-backed M23, which controls large parts of the North and South Kivu provinces south of Ituri.

Early symptoms of Ebola include fever, exhaustion, muscle pain, headaches and a sore throat. These can progress to vomiting, diarrhoea, abdominal pain, rash and impaired kidney and liver function.

The disease spreads through direct contact with the blood or body fluids of an infected person or someone who has died from Ebola.

There is no approved treatment for the Bundibugyo strain of Ebola, responsible for the current outbreak. However, the WHO said on Thursday that its advisory groups had recommended clinical trials of vaccines and treatments. The head of the African Union’s health agency, Jean Kaseya, said a vaccine could be ready by the end of the year.

Neighbouring Uganda, which has recorded one Ebola death and eight additional cases, announced on Wednesday it would immediately close its border with the DRC.

The WHO warned that border closures could drive up informal crossings and make it harder to monitor and contain the disease.

Meanwhile, Kenya’s high court temporarily suspended plans to establish a quarantine and treatment facility for affected US citizens in Kenya. The US had said it would deny entry to its territory to anyone infected with the disease.

The judge, Patricia Nyaundi, ruled that Kenya was not allowed to admit anyone exposed to or infected by Ebola under the proposed deal with the US until a challenge to the deal brought by the Kenyan rights group Katiba Institute was heard.

The group’s lawsuit said the plan “raises grave constitutional concerns regarding the rights to life, health, fair administrative action, public participation and parliamentary oversight”.

Health officials had said the proposal could place additional strain on Kenya’s already stretched healthcare system. The country’s main medical union threatened on Thursday to take strike action unless the terms of the agreement with the US were released within 48 hours.

US officials had said the 50-bed facility at an air force base would become operational on Friday. More than 30 staff from the US Public Health Service, a uniformed branch of the Department of Health and Human Services, left the US for Kenya on Wednesday after receiving three days’ training in Washington DC.

Marco Rubio, the US secretary of state, said on Thursday that the US government planned “to commit $13.5m [£10m] toward Kenya’s Ebola preparedness efforts”, adding that it had already pledged $112m to the regional response to the outbreak.

“The United States’s highest priority remains protecting the health and security of the American people by working to prevent the Ebola outbreak from reaching our shores,” he said.

Ebola has killed more than 15,000 people in Africa over the past 50 years. The deadliest outbreak in the DRC killed nearly 2,300 patients from 3,500 cases between 2018 and 2020.

The WHO said it had received 4.6 tonnes of aid at the airport in Bunia, the capital of Ituri. Unicef, the UN children’s agency, said it would send 100 tonnes of aid.

With Agence France-Presse and Reuters