Nurses working with the WHO prepare to administer Ebola vaccines in Mbandaka, in the Democratic Republic of Congo.

Public health officials are expressing deepening concern that the latest Ebola outbreak in the Democratic Republic of the Congo may be spinning beyond their control and could soon spill over into neighboring countries including Uganda and Rwanda.

With Ebola response teams facing restrictions on their movements in a conflict zone, officials fear containment efforts are falling further behind the virus. And if response teams lose sight of where the virus goes, it could spread undetected and unchecked in places where they cannot safely travel.

“At this point in an epidemic, we’d probably be peaking in terms of knowing where the virus is. And now with the insecurity, that’s compromised,” said Dr. Mike Ryan, assistant director-general of the World Health Organization’s emergency preparedness and response program.

advertisement

To date in this outbreak — DRC’s 10th — there have been 161 cases and 105 deaths.

The threat of a widening epidemic was compounded with a discovery last week that two people infected with Ebola had fled from the Congolese city of Beni to Tchomia, near the border with Uganda, prompting the WHO to warn that the risk that the virus will spread to DRC’s eastern neighbors is “very high.” Previously the risk of regional spread had been assessed as high. (The risk of spread outside the region remains low.)

advertisement

Uganda and Rwanda, with the help of the WHO, the Centers for Disease Control and Prevention, and other international partners, have been preparing for weeks to deal with the possibility of imported cases.

Uganda’s drug regulatory agency has been going through the process of approving a protocol to use an Ebola vaccine being developed by Merck; that vaccine is currently being deployed in DRC in a “ring vaccination” strategy. Under the approach, people who have been in contact with an Ebola case — and the contacts of each contact — are vaccinated to block the virus’s ability to spread.

Uganda is planning to adopt the ring vaccination strategy as well.

But it also intends to pre-vaccinate health workers in high-risk health zones near the DRC border. Initial supplies of vaccine are already in the country and that work could start within days.

“We hope this will start very soon,” said Dr. Socé Fall, regional emergencies director for the WHO’s regional office for Africa. Fall said he expects health workers in Uganda will agree to be vaccinated with the still-experimental vaccine. Uganda has a long history of Ebola outbreaks — it has had more than any other country except DRC.

“Ugandan health care workers — they know Ebola already. They know the risks,” Fall said.

The CDC currently has staff in Uganda working on the vaccination program, said Ray Arthur, a co-leader of the Ebola coordination team for the agency. “The protocols are with the institutional review board, with the government, and the vaccine is in Entebbe,” he said.

Uganda — which has been conducting fever checks at border crossings to identify any possible Ebola cases — is monitoring the health of two people who recently entered the country and who may have been exposed to the virus.

“They are being monitored on the Uganda side to make sure that if something happened they will be isolated very quickly,” Fall said of the two, who haven’t been tested because as yet they haven’t shown symptoms of illness.

Although DRC originally said the pair may have been exposed to Ebola during the burial of an Ebola patient there, officials later determined that was not the case. (Traditional burial ceremonies, in which attendees may touch or kiss the corpse of the deceased, can be major Ebola transmission events. That’s because around the time of death and even after, the skin of a person who died from Ebola teems with viruses.)

There is a sense that Uganda, in particular, is well prepared to cope with imported cases. “Uganda has done a fine job,” Ryan said.

Arthur concurred. CDC has a country office in Uganda, he explained, and other staff from the agency have traveled to the country to help its health ministry identify where Ebola patients could be treated if cases occur. The CDC has also advised the staff on border health issues and infection control — which is critical to ensuring people with Ebola do not infect other patients or the health workers caring for them.

“Should cases come into the country, we would expect transmission would be quite limited,” Arthur said.

Newsletters Sign up for Morning Rounds Your daily dose of news in health and medicine. Please enter a valid email address. Privacy Policy Leave this field empty if you're human:

Preparedness efforts are also underway in Rwanda, which is further from the outbreak epicenter, and in South Sudan.

While experts have some confidence DRC’s neighbors are ready to spot and isolate Ebola cases if there are importations, they appear to feel less assured about how containment efforts are progressing in DRC.

A rebel attack on Beni about 10 days ago killed a number of civilians and led to the declaration of several days of city-wide mourning — days in which shops and schools closed and during which the response teams had to cut back their efforts.

Most importantly the tracking of case contacts suffered, at a time when this critical effort was already failing to register all the people who had been in contact with confirmed cases.

“Our whole strategy is based on knowing where the virus is, identifying cases, identifying contacts, contacts of contacts, isolation, vaccination, community education,” Ryan explained. “And that whole strategy is predicated on a deeper and deeper and more and more precise day-by-day knowledge of where the virus is.”

The health of contacts who are being followed is monitored regularly; if they get sick, authorities ask to take them to Ebola treatment units — in Ebola parlance an ETU — where they can be treated in isolation and where the risk is low that they will infect anyone else.

But contacts who don’t make it onto the follow-up lists don’t get offered vaccine. Because they are not recognized as potential Ebola cases, if they get sick their illness may evade detection. They may end up being cared for at home and being buried without proper precautions if they die. That can result in new infections among caregivers or funeral attendees.

In the last couple of weeks, a number of newly diagnosed Ebola patients were people who were not on a contact list. Five such cases were reported late last week by the WHO.

“You should not have cases occurring which weren’t on a contact list,” Arthur said. “There’s been too many of those in the past two weeks.”

Fall said further investigation showed all five had been in contact with a known case — which is moderately reassuring.

In the midst of an Ebola outbreak, realizing your contact list was incomplete is bad. But finding a case with no discernible link to other cases is worse. That signals that there are chains of transmission that response teams aren’t aware of and aren’t tracking. “Then you lose the virus,” Ryan said. “The virus leaves the trail.”

Drawing up a full list of the contacts of a case is slow and painstaking work, Ryan said — work that isn’t well-suited to a conflict zone.

“Each one of those is an individual detective story. You need to spend time and sit with the family … ‘What happened here? And when did you move there? And what wedding did you go to?’” Ryan explained.

“If you’re looking over your shoulder worrying about a bullet coming through the window or the door, these encounters become very, very strained,” Ryan continued. “Surveillance officers are nervous. And then if you add into that community mistrust and the misinformation, that participation and the acceptance of the community is affected.”

The effort isn’t helped by the fact that there are now cases in multiple different communities in North Kivu and Ituri provinces. That expansion of the area the response teams need to cover has created huge logistical challenges.

“We’re now in nine health zones,” Arthur said. “And the longer the transmission occurs, obviously the greater risk for it to get into an area where’s not good contact tracing or there aren’t vaccination programs in place.”

“Each time there’s extension into a new area, all that infrastructure — laboratories, ETUs, contact tracing, vaccination teams — has to be re-established. And that takes time,” he said. “So I think we’re in a position now where we’re playing catch up and that’s not the kind of position we want to be in.”

Correction: A previous version of this story misspelled Dr. Socé Fall’s name.