What the numbers tell us about the Ebola outbreak
By Jen Christensen, CNN
(CNN) — An Ebola outbreak in the Democratic Republic of Congo (DRC) and Uganda is spreading fast, the World Health Organization said Tuesday. Tests show that a strain called Bundibugyo — which has no specific treatment or vaccine – is behind the outbreak.
The World Health Organization has officially declared the outbreak a “public health emergency of international concern.”
At least one American who was working in the DRC has tested positive for the virus, the international charity Serge reported. The CDC said Tuesday that the American who tested positive was being transferred to Germany for care. The US is also working to move six close high-risk contacts out of the region for monitoring and care.
How many people have died or gotten sick in the DRC?
It’s difficult to know exactly how many people are sick with Ebola. Dr. Anne Ancia, WHO’s representative in the DRC, said Tuesday that there are more than 500 suspected cases, including 130 deaths, but only 30 cases have officially been confirmed.
“We have significant uncertainty about the number of infections and how far the virus has spread,” Ancia said. On Tuesday, the director-general of WHO, Dr. Tedros Adhanom Ghebreyesus, said he is “deeply concerned about the scale and speed” of the deadly outbreak.
How many Americans have been directly affected by the Ebola outbreak?
One American has tested positive for Ebola and has symptoms, according to the US Centers for Disease Control and Prevention.
Six high-risk contacts of that American will be taken to Europe from the affected region, the CDC said Tuesday. Six people – the patient and five others – will be sent to Germany, and another will be cared for in the Czech Republic, according to the CDC.
The symptomatic patient, Dr. Peter Stafford, is a general surgeon who specializes in burn care who was helping patients in the city of Bunia, according to Serge.
Serge says two other doctors – Stafford’s wife, Dr. Rebekah Stafford, and Dr. Patrick LaRochelle – may have been exposed to the virus but remain asymptomatic and continue to follow established quarantine and monitoring protocols.
How does the disease spread?
Ebola spreads through direct contact with fluids from an infected person, such as blood or vomit. It can also spread via objects or surfaces contaminated with an infected person’s fluids or through fecal matter. People are not usually infectious until they show symptoms of the disease.
The incubation period, the time between exposure and the onset of symptoms, ranges from two to 21 days.
Has the outbreak spread to other countries?
In Uganda, there are two confirmed cases as of Tuesday, according to the country’s Ministry of Health. The first was a patient from the DRC who was treated at a Ugandan health facility but later died. The second case is also considered imported from the DRC.
Ugandan health authorities say they have activated outbreak control measures, including disease surveillance, screening and response readiness.
When did this outbreak start?
On May 5, WHO received an alert regarding an unknown illness with high mortality in Mongbwalu, in the DRC’s Ituri province, including four health workers who died within four days of each other.
Is there a patient zero?
WHO says there was a “critical four-week detection gap” between when the first known patient became ill in April and when the disease was identified, allowing Ebola to spread unchecked.
WHO’s Ancia said she doesn’t believe the investigation has turned up a “patient zero” for now. But she said that for a region where Ebola outbreaks are familiar – the last just ended in December – the diagnosis of Bundibugyo was slow to be confirmed, in part, due to the way in which the initial patients showed symptoms and the tests that were available.
What happened with the first confirmed case?
The first confirmed patient to have Ebola Bundibugyo in this outbreak, one of four healthcare workers from Mongbwalu, went to the hospital in Bunia on April 24 with vague symptoms that could have been any number of diseases.
The worker initially had a fever, vomiting and intense malaise. They didn’t have problems with hemorrhaging – a classic sign of Ebola – until the fifth day of infection, according to Ancia. The hospital tested the patient for the most common form of the virus connected to almost all previous outbreaks in the DRC, the Zaire strain, but the tests were negative.
The patient died May 5.
Unaware that the patient had Ebola and that exposure to the body could make people sick, the DRC’s health ministers told reporters Saturday that mourners thought the death was caused by a mystical illness and gathered for a funeral.
Mourners in the region traditionally touch the dead as part of the grieving ritual. The family will also typically wash the body and dress it for burial. The body had been transferred back to Mongbwalu from the hospital and put in a coffin for burial, but more people were exposed when the family chose to go without a coffin, Ancia said. Often, coffins are in limited supply, and the person will be wrapped in a traditional cloth instead, according to local custom. “They changed the coffin. And then there was the funeral, and it’s from there it started,” she said.
It wasn’t until later, when the patient’s samples were sent on to Kinshasa, that additional tests showed that they had been sick with the Bundibugyo strain.
Where did the virus come from?
The first cases of Ebola disease were identified in 1976 in two concurrent outbreaks that started in Sudan and in the DRC, then known as Zaire. Scientists believe that humans first got sick with Ebola after being exposed to infected animals like fruit bats and monkeys, often by eating “bushmeat,” raw or minimally processed meat from wild animals.
The largest outbreak was in West Africa in 2014-16. More than 28,600 cases were reported, but only 15,261 were confirmed; there were more than 11,000 deaths.
There was another large outbreak in the DRC in 2018-20, with 3,481 cases and 2,299 deaths in the DRC, according to WHO. A few cases were also reported across the border in Uganda.
The DRC has officially had 17 outbreaks since 1976, with the most recent being last year.
How deadly is Ebola?
Although it’s rare, scientists consider Ebola a severe and often fatal disease that affects humans and primates.
The case fatality rates vary from 25% to 90%, according to WHO. With the first known outbreak of the Bundibugyo strain in 2007, the case fatality rate was 32%.
What’s different about the strain in this outbreak?
People in this outbreak are testing positive for the Bundibugyo strain.
There are six known strains in the genus Ebolavirus, three of which have caused large outbreaks. Scientists first identified the Bundibugyo strain in 2007 in Bundibugyo district of Western Uganda, a region along the border of the DRC. Bundibugyo is known to have caused two other documented outbreaks: the 2007 outbreak and a second in the DRC in 2012.
Bundibugyo is believed to replicate more slowly and appears to be slower to disable immune cells than other strains, research shows, and that may account for why outbreaks related to this strain have been less lethal. But a slower-moving virus can sometimes stay in the body longer and cause more lingering symptoms. How many treatments or vaccines are there?
Unlike with Ebola Zaire, there are no vaccines or specific treatments for the Bundibugyo strain of Ebola, which could make it difficult to get the outbreak under control.
Supportive care can be beneficial, WHO says. This may include treating dehydration, maintaining oxygen levels and blood pressure, controlling pain and providing nutrition.
Are there restrictions on people traveling from the affected area?
On Monday, the US created entry restrictions for any non-citizen who has been in the region – Uganda, the Democratic Republic of Congo, Congo and South Sudan – in the past 21 days.
The US also elevated DRC to Level 3 status, recommending against all nonessential travel to the area where the outbreak is. The travel advisory for the DRC lists Ituri province as Level 4 (Do Not Travel) area of increased risk and tells Americans not to travel to the area for any reason.
“Right now, there are no cases of Ebola in America. We want to keep it that way, and we are doing everything we can to support Americans in the region,” Heidi Overton, deputy director of the White House Domestic Policy Council, said Monday at a White House event.
How is the US helping with the outbreak?
Years of war and aid cuts, in addition to hostilities in the area, have slashed access to key disease surveillance systems. The CDC said Tuesday that the outbreak is an “evolving situation” but it has provided extensive clinical guidance, training and strict infection control help in the region.
The CDC has worked in the area for decades with 100 staff in Uganda and nearly 30 staff members in the DRC. The agency said it has also brought hundreds of people into the emergency response that it launched two days ago.
The CDC says the overall risk to the US remains low.
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