New Scientist 2018 sep

8 September 2018 | NewScientist | 5

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THE Ebola outbreak in the

Democratic Republic of the

Congo (DRC) has reached a critical

juncture. It seems to be subsiding,

after striking 121 people and killing

81 as of 2 September. But the

coming days may be crucial, says

Tedros Ghebreyesus, head of the

World Health Organization (WHO).

That is partly because the

outbreak is in North Kivu

province in the war-torn east

of the DRC, where fighting by

more than 50 armed groups puts

many areas off limits.

To stop the virus spreading,

medical teams must isolate and

vaccinate anyone who has had

contact with an infected person,

and all the people they in turn

came into contact with. But the

teams can’t work much more than

30 kilometres from the epidemic’s

centre in the city of Beni.

Worse, the UN’s International

Organisation for Migration (IOM)

has found that people in the

region are highly mobile, with

traders and miners transiting

to Uganda and Rwanda, and

a million people have been

displaced by violence.

Such high population mobility,

plus a slow medical response,

caused an Ebola outbreak in

West Africa to mushroom into

an unprecedented epidemic that

killed more than 11,000 in 2014.

This time, the response has

not been slow. The outbreak was

recognised on 1 August, only a

week after an Ebola epidemic

on the other side of the DRC had

been halted. A week later, teams

in North Kivu were vaccinating.

This selective “ring vaccination”

of the contacts of known cases,

then their contacts, makes best

use of limited vaccine stocks by

containing virus spreading from

known cases. It seems to be

working: on 1 September, with

5462 contacts vaccinated, the

WHO reported 13 new cases the

previous week, down from 25 and

35 in the weeks before that.

If that continues, the 300,

doses of vaccine available

worldwide should be more than

enough to contain this epidemic.

But epidemics can hit tipping

points and soar exponentially.

Stopping that requires stopping

all the chains of transmission,

says Mike Ryan, head of

emergency response at the WHO.

Moreover, Ebola epidemics

come in waves: the next surge

could be incubating, or invisible

in violent no-go areas. Worryingly,

four of the new cases reported last

week were not from known chains

of transmission, so there are

unknown chains out there.

They may be hard to find. The

IOM has used its data to choose

the 34 most important transport

hubs where people leave the

region, and Congolese authorities

have so far checked 840,

travellers there for symptoms.

It has also mapped highly

vulnerable spots, such as popular

markets and churches with strong

connections to the outbreak zone,

for closer monitoring.

But the IOM is only able to

monitor relatively safe zones.

“The news of two confirmed cases

in Oicha is extremely distressing,

because the area is almost

entirely surrounded by armed

militants,” says Michelle Gayer

of the US-based International

Rescue Committee.

Last week, a medical team

with a heavy UN military escort

vaccinated 97 contacts of the

two infected people in Oicha,

discovered only because one

travelled to Beni. Anyone in the area

around Oicha cannot be reached.

The WHO also last week decided

to test three antiviral drugs in

randomly chosen patients. No one

will get a placebo, so the trials

can’t establish formally how

much better the drugs are than

getting no drug. But they can

compare the three.

Two people have received

ZMapp, a cocktail of antibodies,

the immune proteins that attack

the Ebola virus. It showed promise

in 2014, but is hard to administer

and must be stored at −80°C,

which is difficult in the DRC. Five

have had remdesivir, a molecule

that blocks the infection process.

The big surprise is that 13 have

been given mAb114, an antibody

from a survivor of the 1995 Ebola

epidemic in Kikwit, DRC, which

can be kept in a refrigerator and

needs only one simple injection.

Last year, a WHO panel judged it

too untested to use in epidemics,

but the US National Institutes of

Health has since rushed through

safety trials in humans. Two

people on it have recovered,

says the WHO, but it is not yet

known if the drug helped. ■

Crunch time for Ebola in the DRC

War zones may thwart efforts to halt virus, reports Debora MacKenzie

JOHN WESSELS/AFP/GETTY IMAGES

A church service near Beni, DRC,

the epicentre of an Ebola outbreak

“ Ebola comes in waves: the

next surge could still be

incubating, or invisible in

violent no-go areas”