It is spreading rapidly in one of the most volatile and vulnerable regions of the world, worrying U.S. and international health officials. Cuts to international health aid over the past year and a half are adding to the burden, some public-health leaders say.
Here is what you need to know about the rare Bundibugyo ebolavirus, how contagious it is and why officials are so worried.
Where is this outbreak occurring, and how fast is the virus spreading?
It is centered in the Ituri province in northeastern Congo, a war-torn area that borders Uganda and South Sudan. The first known patient, a health worker, developed symptoms including fever and vomiting on April 24 and died, according to the World Health Organization. But the virus was spreading before that, possibly for weeks, public health officials have said. It spread further after the health worker’s virus-ridden body was transported home for burial.
As of Monday, there are at least 903 suspected cases including 223 suspected deaths in Congo, and another 291 cases and 43 deaths have been confirmed by laboratory tests, according to the country’s health ministry. There have been nine confirmed cases including one death in Uganda.
Health authorities suspect many more people have been infected and in a wider area. The virus spread undetected for weeks, only 20% of contacts of infected people are being followed up with, and shortages of testing cartridges are slowing identification and confirmation of cases, according to the International Rescue Committee, which is aiding the response. Another complicating factor is that cases have been reported in cities.
This region is a major commercial hub and mining center with lots of traffic. It is densely populated; two million people have been displaced and 10 million face acute hunger. Armed conflict has intensified over the past two months, making it difficult to get health assistance to the area. There is also deep distrust of outside authorities. It took two years to stop an Ebola outbreak here in 2018.
What is the rare strain causing the outbreak?
Bundibugyo is one of four species or strains of Ebola known to infect humans, named after a mountainous district in Uganda where the first outbreak took place in 2007.
It has caused only two previous outbreaks and is so rare that it wasn’t included in lab tests for Ebola where the latest outbreak occurred, which delayed its identification, according to international health officials. Bundibugyo virus was confirmed when samples were sent thousands of miles across the country to a government research lab.
Is Bundibugyo virus more dangerous or contagious than other Ebola viruses?
No. The virus replicates more slowly and appears to be less deadly than the more common Zaire ebolavirus, according to studies. The Zaire strain was responsible for an explosive epidemic in West Africa in 2014 that killed more than 11,300 people—the largest Ebola outbreak in history. But the Bundibugyo strain still killed more than 30% of those it infected in the past two outbreaks.
There are no approved vaccines or treatments, which makes the outbreak that much riskier.
What are the chances that Ebola will spread to the U. S.?
The risk is low, according to the Centers for Disease Control and Prevention. U.S. officials have prohibited foreigners who have been to Congo, Uganda or South Sudan in the last three weeks from entering the country. U.S. citizens who have been to those countries are being directed to four U.S. airports and screened there, the CDC said. Those airports are: Washington-Dulles International, Hartsfield-Jackson Atlanta International, George Bush Intercontinental and John F. Kennedy International.
The U.S. has a network of specialized treatment centers around the country to care for patients with dangerous pathogens like Ebola and hantavirus, at hospitals such as the University of Nebraska Medical Center and Emory University Hospital. However, U.S. authorities evacuated an American medical missionary who contracted Ebola in Congo to a hospital in Germany with similar capabilities, and aim to build an Ebola quarantine and treatment facility in Kenya. A Kenyan high court put the U.S. plan on hold.
What are the symptoms of Ebola?
Early symptoms resemble those of other, more common diseases: fever, fatigue, muscle pain, headache and sore throat. These are known as Ebola’s “dry” symptoms, and they are often mistaken for malaria. After four or five days, a patient may develop “wet” Ebola symptoms: watery diarrhea, nausea and vomiting. Organ dysfunction may occur and in some cases, internal and external bleeding from the nose, or in diarrhea.
How does Ebola spread, including this strain? Could it cause a pandemic?
Ebola spreads through touching sweat, blood and other bodily fluids of infected people. A body is even infectious after a person dies, making burial rituals that involve touching a deceased person, a common practice in this region, especially risky.
Ebola is very deadly, but unlikely to cause a pandemic because it doesn’t spread easily. It isn’t airborne like Covid or the flu, and you can’t get Ebola simply from being near a person with it. The incubation period is between two and 21 days, and people aren’t usually contagious before symptoms.
What vaccines and treatments are in development for this particular Ebola strain?
Two vaccines and two treatments are approved for the Zaire strain of Ebola. Even though Bundibugyo virus is in the same family of viruses, the genes that vaccines and drugs target differ significantly.
Several potential Bundibugyo vaccines are in development, but they haven’t been tested in humans and preclinical data are limited, according to the Coalition for Epidemic Preparedness Innovations, which funds vaccine development. Manufacturing and preclinical studies will be done at the same time so that doses are ready as soon as possible for human trials in the outbreak zone, according to CEPI.
CEPI is investing to fast-track three potential vaccines, including up to $50 million for preclinical and early human testing of a Moderna investigational mRNA vaccine.
Another potential vaccine that CEPI is investing in, with up to $3.2 million in funding, is built on the same platform used for an approved vaccine for the Zaire strain. Research at the University of Texas Medical Branch found that the investigational vaccine protected nonhuman primates against Bundibugyo virus. The vaccine will be further developed and tested in humans by IAVI, a nonprofit biomedical research organization.
The investigational vaccine is the most promising of those in development against the Bundibugyo strain, said Dr. Vasee Moorthy, a WHO official. It will likely take six to nine months to get doses ready for a clinical trial, he said.
CEPI is also investing up to $8.6 million for preclinical testing and preparations for early human trials of a vaccine developed by researchers at the University of Oxford, working with the Serum Institute of India, the world’s largest vaccine manufacturer. The investigational vaccine will use the same platform behind a Covid-19 vaccine developed by Oxford and AstraZeneca. It could be available in two or three months, but the shot has yet to be tested even in animals, Moorthy said.
Mapp Biopharmaceutical has a potential treatment that protected against the Bundibugyo strain in preclinical studies, and an early-stage clinical trial showed it is safe in humans. Developed with U.S. government funding, it is a monoclonal antibody treatment.
Gilead Sciences’ investigational antiviral, obeldesivir, is predicted to be active against the Bundibugyo strain, a spokesperson said, and the company is working with global public-health authorities.
Its drug remdesivir, which was used to treat Covid, also inhibited the Bundibugyo strain in one lab study.
