(Bloomberg) — A rare strain of Ebola with no approved vaccine or treatment circulated undetected for weeks in the conflict-torn northeastern Democratic Republic of Congo before killing at least 87 people.
The first case developed symptoms on April 24, causing a four-week delay in detection that allowed for widespread uncontrolled community transmission, Africa Centers for Disease Control and Prevention director general Jean Kaseya said in an online briefing on Saturday.
About 336 potential cases have been reported, mainly in Mongbwalu and Rwampara health zones in Ituri province near the Ugandan border, with other possible infections in the provincial capital Bunia, Kaseya said. Among the laboratory-positive cases, four deaths were confirmed.
Laboratory tests conducted by the National Biomedical Research Institute in Kinshasa confirmed that the outbreak is caused by the Bundibugyo strain. The virus has caused only two previous known outbreaks: in Uganda in 2007 and in eastern Congo in 2012. The deaths and suspected cases in this cluster have already exceeded those of the previous two outbreaks of this type combined.
“Every day, more than 70% of disease outbreaks in Africa are in this area,” Kaseya said. “That’s why we need to cover the region, cover the continent, and I’m calling on partners” to support the countries most at risk.
Ebola is among the deadliest infectious diseases in the world, killing about a quarter to nearly 90% of people infected, depending on the type of virus and available medical care. Discovered in 1976 near the Ebola River in what is now the Democratic Republic of the Congo, the Zaire strain had caused a devastating West African epidemic about a decade earlier and received the most research funding, leading to licensed vaccines and treatments.
“Ebola Zaire is the one that’s gotten all the attention, and for very good reasons,” Susan McLellan, director of biocontainment care at the University of Texas Medical Branch, said in an interview. Development of medical countermeasures, including monoclonal antibodies and vaccines, is less advanced for Bundibugyo, she said.
The Africa CDC and the World Health Organization convened scientific experts this week to review possible therapies and vaccines and discuss accelerated plans to study their effectiveness, including whether existing vaccines can offer cross-protection against different strains of Ebola, said Shanelle Hall, the CDC’s senior adviser for management and operations in Africa.
Health officials are considering four potential Ebola treatments for use in randomized controlled trial protocols in Congo and Uganda, including monoclonal antibodies, Gilead Sciences Inc.’s remdesivir. and an oral version of the antiviral, she said.
Discussions with both governments are ongoing, although no trials have yet started, Hall said. Laboratory research has shown that the strain may be more susceptible to antivirals than Ebola Zaire.
Several vaccine candidates are also under review. While Merck & Co.’s Ervebo vaccine is under consideration, most existing Ebola vaccines have been developed for Sudan and Zaire strains rather than Bundibugyo. Early candidates focusing on the Bundibugyo tribe from groups including Oxford University and Moderna Inc. are also being considered.
Ervebo injections remain too expensive for routine use at about $98.60 per dose and also require ultra-cold storage, complicating deployment in remote areas, Hall said. Work is underway on a new generation of Ebola vaccines that would be easier to store, cheaper to manufacture and potentially protect against multiple strains of Ebola, including Bundibugyo.
Uganda also confirmed a case of Bundibugyo Ebola in a Congolese patient who traveled across the border for treatment and died in an intensive care unit in Kampala on May 14 after worsening with bleeding symptoms. Authorities said the body was flown back to Congo that evening, highlighting the risk of cross-border transmission through the movement of patients and infected remains.
WHO and Africa CDC are deploying additional epidemiologists, laboratory specialists and infection control experts to Ituri while airlifting five metric tons of emergency supplies including testing equipment, protective gear and treatment materials.
The outbreak is taking place in a remote part of eastern Congo more than 1,700 kilometers (1,100 mi) from Kinshasa. Security risks, poor roads, mining-related population movements and frequent cross-border travel complicate the response.
Mongbwalu lies in one of the nation’s gold mining areas, where tens of thousands of people move between remote mining camps and nearby commercial centers. The region is also plagued by armed groups and weak infrastructure, complicating efforts to deliver medical supplies and disease and contact tracing.
“Getting access to Mongbwal is not easy,” said Jimmy Munguirek, Congolese director for advocacy group Resource Matters. “The road is not there.”
The area has only one main hospital, Munguirek said, adding that crowded mining settlements and the constant movement of workers could accelerate transmission if the outbreak is not quickly contained.
The US Embassy in Kinshasa on Saturday warned American citizens not to travel to Ituri “for any reason”, highlighting security concerns and limited medical infrastructure in the region.
“These zones are full of people who come from all over to work in artisanal mining,” Munguirek said. Armed groups active in the area and mistrust of health authorities could also hamper containment efforts, he said: “There is a big risk that things will get worse.”
Congo’s health ministry said the suspected first case was a nurse who died at an Evangelical medical center in Bunia. Patients had fever, weakness, vomiting and, in some cases, bleeding, according to the WHO, which said several cases deteriorated rapidly and died.
Ebola is spread through direct contact with the bodily fluids of infected people or contaminated materials. The risks of transmission can skyrocket in environments where people don’t have reliable access to running water and sanitation, said McLellan, who worked in West Africa during the 2013-2016 Ebola epidemic.
“It takes a very small amount of material,” she said, describing how body fluids can remain on skin or surfaces when handwashing and sanitation are limited.
Still, experts stressed that Ebola does not spread easily through casual contact and that the risk outside the region remains low.
“There is no documented sustained spread of Ebola outside of Africa,” Imperial College London researchers said in an analysis published Friday, noting that exported cases during the West African epidemic were rare and mostly involved health workers.
Congo has extensive experience in responding to Ebola outbreaks, having battled more than a dozen outbreaks over 50 years. The country’s last outbreak, declared in December, was contained within weeks. The Congolese government said it was deploying rapid response teams and urged residents to avoid contact with sick people, infected animals and bodily fluids while thoroughly cooking meat, especially bushmeat.
The outbreak comes as some global health experts warn that cuts to US foreign aid and public health programs could weaken disease surveillance and emergency response capacity in volatile regions. A study published Thursday in Science found that the sudden withdrawal of USAID funding was linked to increased conflict in parts of Africa heavily dependent on aid.
The Africa CDC said it is not recommending travel restrictions or border closures at this stage, arguing that effective public health measures such as testing, screening and contact tracing are more effective in limiting transmission.
Officials said earlier intervention around infected individuals could potentially have reduced cross-border spread between Congo and Uganda, underscoring the importance of rapid detection and containment, rather than movement restrictions.
(Update includes death in first paragraph, CDC Africa comment in fourth, treatment option starting in eighth)
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