The Ebola outbreak in the Democratic Republic of Congo has killed at least 88 people and infected hundreds more, prompting the World Health Organization to declare an international health emergency on Sunday.

Authorities warn there is no vaccine for the Bundibugyo strain driving the crisis, which has now spread across the border into Uganda.

What is the WHO’s Ebola emergency declaration?

The WHO designated the outbreak a “public health emergency of international concern,” the second-highest alert level under international health regulations.

The agency stopped short of declaring a pandemic emergency, the highest tier introduced in 2024, but warned the true scale of infections and geographic spread remains unclear, with the real case count likely far higher than currently reported.

Why is the Bundibugyo strain so dangerous?

The Bundibugyo strain has no approved vaccine and no specific treatment, DR Congo Health Minister Samuel-Roger Kamba said. The strain, first identified in 2007, carries a fatality rate of up to 50 percent.

Vaccines exist only for the Zaire strain, identified in 1976, which has a higher fatality rate of 60 to 90 percent but a proven immunization option.

The outbreak was confirmed Friday in Ituri province in northeastern DRC, bordering Uganda and South Sudan, according to the Africa Centres for Disease Control and Prevention. The strain has also killed one Congolese national in Uganda, officials confirmed Saturday.

Patient zero was a nurse who arrived at a health facility in Ituri’s provincial capital, Bunia, on April 24 with symptoms consistent with Ebola. Symptoms of the disease include fever, hemorrhaging and vomiting.

How bad are conditions on the ground?

“We’ve been seeing people die for the past two weeks,” said Isaac Nyakulinda, a local civil society representative reached by AFP. “There is nowhere to isolate the sick. They are dying at home and their bodies are being handled by their family members.”

Medical aid group Doctors Without Borders (MSF) said it was preparing a “large-scale response” and mobilizing medical and support staff to the area.

MSF Emergency Programme Manager Trish Newport called the pace of spread “extremely concerning,” citing the number of cases and deaths recorded in such a short period across multiple health zones and into a second country.

Logistics compound the challenge. DR Congo is home to more than 100 million people and is four times the size of France, but its communications infrastructure is limited, making the large-scale transport of medical equipment difficult.

What is the risk of further spread?

This is the 17th Ebola outbreak to hit the DRC, and officials say the risk of wider spread is significant.

The WHO cited the high positivity rate of initial samples, the confirmation of cases in two countries, and a rising number of suspected cases as signs the outbreak may be “potentially much larger than what is currently being detected.”

The previous outbreak, which struck the central region last August, killed at least 34 people before being declared eradicated in December.

The deadliest DRC outbreak, between 2018 and 2020, killed nearly 2,300 people. Across Africa over the past 50 years, Ebola has killed around 15,000 people.

How does Ebola spread?

Ebola spreads through direct contact with the bodily fluids or blood of an infected person. A person becomes contagious only after symptoms appear, and the incubation period can last up to 21 days.

The virus, believed to have originated in bats, can cause severe bleeding and organ failure. Mortality rates across outbreaks over the past half century have ranged from 25 percent to 90 percent, according to the WHO.