International aid organizations, already stretched to the limit by the biggest Ebola outbreak on record, are facing a second, probably unrelated cluster of cases in the Democratic Republic of the Congo (DRC). DRC’s Ministry of Health yesterday notified the World Health Organization (WHO) of the outbreak in the north of the country. It said 13 of the 24 people suspected to have contracted Ebola have died.
“At this time, it is believed that the outbreak in DRC is unrelated to the ongoing outbreak in West Africa,” says a WHO statement issued today. None of the patients had traveled to the regions in West Africa where Ebola is now spreading or had contact with persons from those regions. Early results from a lab in DRC also indicate that the disease was not caused by Ebola-Zaire, the virus species causing the outbreak in West Africa. Since December, Ebola-Zaire has sickened at least 2615 people in Liberia, Sierra Leone, Guinea, and Nigeria and killed 1427 them. It is the biggest Ebola outbreak on record.
While that outbreak is the first in that region, the new outbreak in DRC comes in a region more used to dealing with the virus. “This is the country that has the most experience of dealing with the virus and that gives me some hope,” says Stephan Günther, a virologist at the Bernhard Nocht Institute for Tropical Medicine in Hamburg, Germany, who is currently working in a mobile lab in Nigeria. DRC (formerly Zaire) has seen seven outbreaks including the first one on record in 1976.
“It is important to understand that this outbreak has come to the attention of the government quite early and is being dealt with by a group of people who know how to control an Ebola outbreak,” says David Heymann, an epidemiologist at the London School of Hygiene & Tropical Medicine. At the same time, Heymann adds, “It’s impossible to know at this point what the country will request and what they can do on their own.”
According to WHO, the index case of the new outbreak was a pregnant woman in the Ikanamongo Village in northern DRC. She was probably infected when she butchered a bush animal given to her by her husband. Jonathan Epstein, a veterinary epidemiologist at EcoHealth Alliance in New York City, calls it “almost a classic case.” It is known that chimpanzees, bats, and other animals can carry the deadly Ebola virus, and the pathogen often spills over into the human population when people eat infected animals. The new outbreak shows “that we also need to pay attention to the broader situation,” Epstein says. “There is a need for more outreach and education.” Reducing risky behavior like eating bushmeat is an important public health goal, Heymann agrees. “It’s a sign that we need to really look seriously at how to prevent these outbreaks from occurring,” he says.
The infected woman was treated in a private clinic in Isaka Village and died on 11 August. A doctor and two nurses who treated the woman, as well as the hygienist and a ward attendant, infected themselves at the hospital and all later died. “Other deaths have been recorded among the relatives who attended the index case, individuals who were in contact with the clinic staff, and those who handled the bodies of the deceased during funerals,” the WHO statement notes. Some 80 people who have had contact with the patients are being monitored, and more contacts are being traced.
Samples from the current outbreak in DRC are being tested at a WHO collaborating center in Gabon and the results are expected later today, according to a WHO representative. Apart from Zaire ebolavirus, there are four other species of Ebolavirus: Sudan, Reston, Bundibugyo, and Taï Forest.
Of those four, Sudan is by far the most common. Reston virus infection has been documented in humans without causing illness, and the only case of Taï Forest virus infection in a human is a scientist who had conducted an autopsy on an infected chimpanzee. Sudan ebolavirus, on the other hand, has caused several outbreaks and sickened close to 800 people since it was discovered after an outbreak in Sudan in 1976. About half the patients died.
The only other Ebola virus that has caused large outbreaks is Bundibugyo ebolavirus. It was first discovered in an outbreak in Uganda that started in December 2007 and killed 37 people. Two years ago, it caused an outbreak in DRC.
*The Ebola Files: Given the current Ebola outbreak, unprecedented in terms of number of people killed and rapid geographic spread, Science and Science Translational Medicine have made a collection of research and news articles on the viral disease freely available to researchers and the general public.