Ebola likely circulating in Congo for two months, outbreak to grow, WHO says

GENEVA — The Ebola outbreak in eastern Democratic Republic of Congo, linked to more than 130 deaths, likely began around two months ago and is expected to continue spreading, the World Health Organization (WHO) said Wednesday.

The outbreak involves the rare Bundibugyo strain, for which no vaccine exists. Declared last Friday, it has alarmed experts due to how long it remained undetected while spreading through densely populated areas, making it difficult to trace and isolate contacts.

The WHO previously highlighted a "critical four-week detection gap" between the onset of the first known case and laboratory confirmation of the outbreak.

"Investigations are ongoing to determine when and where exactly this outbreak began," Anais Legand, WHO technical officer for viral threats, told reporters in Geneva. "Given the scale, we believe it probably started a couple of months ago."

Congo has faced 16 previous Ebola outbreaks, but first responders report shortages of essential supplies, including painkillers, face masks, and motorcycles for tracing contacts, hampering efforts to contain the disease.

Public Health Emergency

So far, 600 suspected cases and 139 suspected deaths have been reported. Fifty-one cases have been confirmed by laboratory testing in Congo, with two additional cases confirmed in neighboring Uganda, WHO Director-General Tedros Adhanom Ghebreyesus said.

Tedros noted that a WHO Emergency Committee met Tuesday and confirmed the outbreak as a public health emergency of international concern, though not a pandemic-level emergency. He had declared the emergency over the weekend without first consulting experts, citing the urgency of the situation.

“The WHO assesses the epidemic risk as high at the national and regional levels and low at the global level,” Tedros said.

Super-Spreader Event Suspected

The Bundibugyo strain has an average fatality rate of about 40%. Unlike the more common Zaire strain, no virus-specific therapeutics or vaccines are approved, and testing capacity is limited. Two vaccines are under consideration but may take three to nine months to be developed.

A 2018–2020 outbreak of the Zaire strain in eastern Congo killed nearly 2,300 people, making it the second-deadliest on record.

“Our top priority is identifying all existing chains of transmission, which will allow us to define the scale of the outbreak and provide care,” said Chikwe Ihekweazu, WHO emergencies chief.

WHO experts suspect the outbreak began a couple of months ago, with the first suspected death reported on April 20. They believe a super-spreading event, possibly at a funeral or healthcare facility, followed that death. Delays in confirming the outbreak were reportedly caused by missteps from medical personnel, including failure to escalate samples after initial tests came back negative for the Zaire strain.

International Support

An American doctor working in Congo is among the confirmed Ebola cases. He was transferred to Germany, while his family is in isolation at the same hospital. Another U.S. doctor exposed to the virus is being transferred from Uganda to a hospital in Prague.

The U.S. government has mobilized an initial $13 million to respond to the outbreak and plans to help open 50 clinics for Ebola treatment. South Africa has pledged $2.5 million to support the response, according to the Africa Centres for Disease Control and Prevention.

Experts note that delays in detecting the outbreak may reflect gaps in preparedness, partly due to funding cutbacks by the U.S. and other major global health donors. Tedros said it was too early to assess whether these cuts contributed to the outbreak’s late detection.

-Reporting by Olivia Le Poidevin and Jennifer Rigby; Writing by Aaron Ross and David Lewis; Editing by Madeline Chambers, Alison Williams, and Hugh Lawson/Reuters