The Ebola Outbreak in Africa Was Declared a Global Health Emergency by the WHO. Here’s What to Know About the Rare but Severe Illness

The international health agency notes that the outbreak does not meet the criteria for a pandemic, and the U.S. Centers for Disease Control and Prevention says that the risk to the American public is low

Sara Hashemi | Daily Correspondent

May 18, 2026 3:16 p.m.

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On May 17, the World Health Organization (WHO) declared that an outbreak of the rare but deadly disease Ebola in the Democratic Republic of the Congo (DRC) and Uganda is a public health emergency of international concern.

Still, the agency stresses that the event “does not meet the criteria of pandemic emergency,” such as Covid-19, and recommends that countries keep their borders open. The U.S. Centers for Disease Control and Prevention (CDC) states that the current risk of Ebola to the American public is low.

The DRC has reported ten laboratory-confirmed cases of an Ebola-causing virus, as well as more than 300 suspected cases and almost 90 suspected deaths, per the CDC. Two additional cases, including one death, were confirmed in Uganda among individuals who had traveled to the DRC. However, there are probably many more cases than what has been reported so far, per the Associated Press’ Chinedu Asadu and Saleh Mwanamilongo.

The WHO’s emergency declaration is meant to trigger a coordinated international response and mobilize funding to fight the disease outbreak. But public health experts worry that reports of an outbreak came too late—the WHO generally picks up a surge in cases much earlier, says Jennifer Nuzzo, an epidemiologist and director of the Pandemic Center at the Brown University School of Public Health, to Yan Zhuang, Matthew Mpoke Bigg and Apoorva Mandavilli at the New York Times.

The first known suspected case was a health care worker who reported symptoms including fever and hemorrhaging on April 24. The individual, who later died, was in the DRC’s Ituri province, located in the northeastern part of the country.

This person was unlikely to have been the first case in the outbreak; they were probably exposed to the virus by someone seeking care, who may have caught it from an animal or another ill individual, reports Helen Branswell at STAT. So, the virus may have been spreading in the DRC for a while.

Ebola’s early symptoms resemble the flu and can include fever, weakness, muscle and joint aches, severe headache and sore throat. A few days later, however, they can progress into “wet” symptoms, such as vomiting, diarrhea, loss of appetite and unexplained bleeding.  

These signs of illness typically appear between 2 and 21 days after exposure to an Ebola-causing virus. The moderately contagious disease is transmitted through direct contact with blood or other bodily fluids, as well as through surfaces contaminated with fluids from a sick person. Infected animals, such as bats, primates and forest antelopes, might also spread Ebola-linked viruses to humans.

The current outbreak was caused by the Bundibugyo virus, a rare species for which there are no approved vaccines or therapeutics. The disease is fatal in about 30 percent of people who contract this pathogen.

Only two previously documented outbreaks have been caused by the Bundibugyo virus, says Siouxsie Wiles, a microbiologist at the University of Auckland in New Zealand, to Rachel Fieldhouse and Mohana Basu at Nature. The first was reported in 2007 in Uganda’s Bundibugyo district, and the second in 2012 in the DRC. Collectively, the countries have had more than 20 Ebola outbreaks, reports the AP’s Chinedu Asadu.

The public health response will be complicated by the DRC’s large network of informal health care facilities and ongoing humanitarian crisis, largely caused by conflict in the nation, says the WHO. The country has “a very mobile population who are trying to escape the conflict,” Wiles tells Nature. Contact tracing and disease surveillance efforts will need to be scaled up to mitigate the spread of Ebola, reports the outlet.

STAT also reports that several Americans currently in the DRC may have been exposed to the Ebola-causing virus. At least one person may have developed symptoms, per the outlet, but there are no test results available for these individuals.

The CDC is “supporting interagency partners who are actively coordinating the safe withdrawal of a small number of Americans who are directly affected by this outbreak,” per the agency’s statement.  

Sara Hashemi | Read More

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.