An Ebola virus outbreak in the Democratic Republic of Congo and in Uganda has caused over 500 suspected cases, including over 130 deaths, the World Health Organization said on Tuesday.
“I’m deeply concerned about the scale and speed of the epidemic,” Tedros Adhanom Ghebreyesus, the director general of the W.H.O., said at a meeting of the organization in Geneva.
The U.S. Centers for Disease Control said on Monday that it was restricting entry into the country for some travelers, among other steps that it said were meant to prevent the spread of Ebola. The W.H.O. has declared the outbreak “a public health emergency of international concern.”
The type of Ebola virus behind the latest outbreak, known as Bundibugyo, is rare. Fewer field tests for it are available, and this form of the virus has no targeted vaccine or treatment, making it harder to contain.
Here’s what to know:
Where did the outbreak start?
It is not yet known exactly when this outbreak started, but it was first identified in May in the Democratic Republic of Congo’s northeastern Ituri Province. Laboratory testing has definitively linked only 30 cases there to the virus, the W.H.O. said. Two cases, including one death, have been confirmed in Uganda among people who had traveled to Congo.
There are large numbers of people in Ituri who have been displaced by conflict and many migrant laborers drawn to its gold mines. Dr. Tedros said “significant population movement” in the region increased the risk of the virus spreading.
Early surveillance and testing failed to identify the rare species of Ebola responsible for the current outbreak, delaying the response from the health authorities. Five countries in the region have started screening travelers or tightening border controls.
How is the United States responding?
A C.D.C. order issued on Monday allows the United States to bar foreigners from entering the country if they have been in the Democratic Republic of Congo, Uganda or South Sudan in the previous 21 days. The order will remain in place for 30 days.
“At this time, C.D.C. assesses the immediate risk to the general U.S. public as low,” the agency said on Monday. But the U.S. authorities said they were enhancing public health screenings and monitoring of travelers from the affected areas.
The agency said it was coordinating with airlines and port-of-entry officials internationally to identify travelers who may have been exposed to the virus. At the national level, the C.D.C. said it was enhancing health protections at ports, contact tracing, laboratory testing capacity and hospital readiness.
The United States is also working to move an American medical missionary in Congo who tested positive to Germany for treatment and monitoring, along with other “high-risk contacts.”
The United States withdrew from the W.H.O. in January, and the U.S. Agency for International Development, which has played a major role in containing previous outbreaks, was shuttered last year by the Trump administration.
It is unclear how that might have affected the response to this outbreak. Atul Gawande, a former senior U.S.A.I.D. official, suggested that it may have gone undetected for weeks because American agencies had been scaled back. “Speed is everything,” he said.
What is Ebola?
Ebola is an illness caused by a group of related viruses, known as orthoebolaviruses, first discovered in 1976 in the countries now known as South Sudan and the Democratic Republic of Congo, in a region near the Ebola River. Fruit bats are thought to carry the viruses without being sickened by them.
Ebola outbreaks have mostly occurred in sub-Saharan Africa. Four of the six known species of Ebola viruses cause illness in humans and can be fatal.
People stricken with Ebola may first experience so-called dry symptoms such as fever, aches, pains and fatigue before progressing to wet symptoms, including diarrhea, vomiting and bleeding, according to the C.D.C.
Ebola can be contracted through contact with the bodily fluids of an infected, sick or dead person and through contact with contaminated objects like clothing, bedding, needles or medical equipment.
Are there vaccines?
Vaccines and an antiviral drug have been approved for the Zaire species of Ebola, the most common one. But there is no vaccine or specific treatment for the Bundibugyo species, as outbreaks of it have been rare.
The Bundibugyo virus was first identified in 2007 after a mysterious illness broke out in the Bundibugyo District in Uganda, which borders Congo. In 2012, another such outbreak was identified in Congo.
In January, scientists at the University of Oxford announced an effort to develop and test vaccines to protect against multiple lethal viruses, including Bundibugyo.
Fatality rates during the last two outbreaks of this form of Ebola have ranged from 30 percent to 50 percent of those infected, according to the W.H.O.
The incubation period for this species of the Ebola virus ranges from two to 21 days, and individuals are usually not infectious until symptoms manifest. But because the early symptoms — like fever and fatigue — resemble those of other illnesses, including malaria, early detection can be difficult.
There have been several deadly Ebola outbreaks in recent years.
Ebola has resurfaced repeatedly since its discovery in 1976, when dual outbreaks in South Sudan and Congo infected nearly 600 people and killed more than 430.
In the 21st century, there have been a number of deadly outbreaks of Ebola viruses.
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2025: Last year, health officials in Congo officially declared the country’s 16th Ebola outbreak since 1976. There were 53 confirmed cases and 45 deaths. Earlier that year, Uganda also reported 12 confirmed cases and four deaths from Ebola.
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2019: A severe outbreak led to nearly 3,500 cases in Congo, with nearly 2,300 deaths.
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2014: An Ebola epidemic in West Africa began in 2014 and ended in 2016. It was the largest such epidemic in history, with cases in southeastern Guinea, Liberia and Sierra Leone. More than 28,600 people fell ill and more than 11,300 died. There were also cases reported in Congo, Mali, Nigeria, Senegal, Spain, Britain and the United States.
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2007: About 130 people in Uganda fell ill with the Bundibugyo virus, and more than 40 people died. In Congo, there were more than 260 cases related to the Zaire species of the Ebola virus, and more than 70 percent of the cases resulted in death.
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2003: Two outbreaks in the Republic of the Congo led to about 180 cases and 170 deaths.
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2000: About 425 people fell ill during an outbreak in Uganda; more than half died.
Brian Otieno contributed reporting from Nairobi, Kenya.
Ephrat Livni is a Times reporter covering breaking news around the world. She is based in Washington.
The post What to Know About the Ebola Outbreak as Cases and Deaths Rise appeared first on New York Times.
