Ebola outbreak in DRC is 'ongoing' but WHO is 'cautiously optimistic'

"The outbreak is ongoing," said Dr. Peter Salama, WHO deputy director-general of emergency preparedness and response, in a webcast on Twitter. Salama said he is "cautiously optimistic."

Ebola virus disease, which causes fever, severe headache and in some cases hemorrhaging, most commonly affects people and nonhuman primates, such as monkeys, gorillas and chimpanzees. The current outbreak is caused by the Zaire ebolavirus, one of five separate subtypes and the one with the highest mortality rate, ranging from 60% to 90%, according to WHO.

Beginning with the 1976 discovery of Ebola in an area that is now the Democratic Republic of Congo, the country has experienced nine outbreaks.

In the past week, one new person was confirmed to suffer from the hemorrhagic disease in Iboko, along with five suspected cases, including two in Bikoro and three in Wangata, all regions within the Equateur province. Equateur has an estimated population of 2.5 million spread among 16 health zones, according to WHO.

Salama's optimism arises from the fact that there have been no new reports of illness in Mbandaka, the Equateur province capital, which boasts a population of 1.2 million.

"What this is telling us is the response (the WHO's vaccination program) is having an impact in those two locations," said Salama.

'Positive effect'

Since the launch of the vaccination program on May 21, 1,826 people have been vaccinated, the Ministry of Health of the Democratic Republic of Congo reported Wednesday. This figure includes 673 people in Mbandaka, 398 in Bikoro, 725 in Iboko, and 30 in Ingende, also located in the Equateur province.

WHO has been working with the Ministry of Health and international partners, including Médecins Sans Frontières (Doctors Without Borders) to inoculate only those people at high risk of infection: primary and secondary contacts.

"It's extremely likely the vaccine has had a positive effect," said Salama, basing his assessment on the fact that in Mbandaka there have been no confirmed cases since mid-May and a large portion of contacts have been vaccinated there.

Still, everyone remains on "high alert," he said, adding that two new confirmed cases in Iboko at the end of May and a single case on June 2 "tells us a lot about why we need to refocus our response."

Ebola virus spreads through direct contact with either bodily fluids or objects contaminated by someone ill with the disease, according to the US Centers for Disease Control and Prevention. In some cases, the virus is spread from contact with someone who has died from the disease. The virus enters the body through broken skin or mucous membranes in the eyes, nose or mouth. People can get it through sexual contact, as well.

Phase 1 of the vaccination campaign, a plan to protect urban centers and towns, has "gone well," said Salama. During this phase, the plan is to inoculate all health care workers and family members and others who have come into close contact with the ill. "We've reached the majority of contacts -- more than 98% -- with vaccination... and we believe these contacts are now protected against Ebola," he said.

Phase 2 of the vaccination campaign will turn the focus of the response to rural and isolated communities, "some of the most remote territories on earth" and home to "indigenous" and "marginalized" populations, he said.

'Boots on the ground'

On the front lines of the outbreak, health officials use a tool called contact tracing to break the chain of transmission of the Ebola virus. It's the identification and follow-up of all people who may have come into contact with a person infected with the infectious disease. Health workers monitor close contacts for 21 days and isolate them should they become ill.

"Overall, the contact tracing has been a huge challenge, particularly in areas hardest to reach," said Salama, noting that Iboko is most difficult. The infrastructure is only beginning to catch up, he added, with motorcycles arriving now. It's a "major boots on the ground" effort that takes several hours to trace each and every contact, he said.

"Tough work is going to go on for the next weeks," said Salama.

Dr. Vasee Moorthy, WHO research coordinator, said there are four unlicensed Ebola treatment products currently available in country: ZMapp (a product of Mapp Biopharmaceuticals), Remdesivir (GS-5734, a product of Gilead), REGN-EB3 (an experimental Regeneron Pharmaceutical product), and a monoclonal antibodies treatment created by the US National Institutes of Health

On Monday, the Ministry of Health approved the use of these experimental treatments, some used on patients in past outbreaks, during the current outbreak.

"It's clearly very difficult to evaluate efficacy of Ebola products in outbreaks," said Moorthy, who said scientists rely on efficacy data derived from experiments in non-human primates (monkey models). Some of these treatments, when given as late as day five of symptoms, led to high protection in monkeys, he said, adding that the choice of product for each patient will be decided by clinicians.

Most recently, a team of Chinese experts will arrive in Kinshasa on Friday to join the international effort, which includes nations from the European Union, Japan and the United States in assisting the Congolese health authorities, according to the Ministry of Health.

"We're cautiously optimistic but there's a lot of work," said Salama. "We've learned the hard way in the past to never underestimate Ebola."