An outbreak of the deadly Ebola virus is on the rise in a regional trading hub in Congo as terrified residents, including those who have been infected, avoid health care workers.
Public health officials have watched with mounting concern in the last week as the number of cases of Ebola in the heavily populated North Kivu and Ituri Provinces have grown, more than two months after the outbreak was identified.
The Congolese Health Ministry said Wednesday that 194 cases of hemorrhagic fever have been reported in the two provinces in eastern Congo, along the border with Uganda.
That's an increase of 32 cases in just a single week, a startling number for a virus that usually dies down soon after public health officials begin treating the outbreak.
One hundred twenty-two people have died so far. Another 53 people have been discharged from Ebola treatment centers after having survived the disease.
In a typical Ebola outbreak, the number of cases begins to fall after public health officials begin interceding to stop the spread of the virus.
"Usually, by this point in the response, we would have hoped to see no more cases," said Tarik Jasarevic, a spokesman for the World Health Organization who visited the cities at the center of the outbreak last month.
Public health officials responding to the mounting outbreak are closely watching Beni, a city of about a quarter of a million residents and an important regional trading hub with ties to nearby Uganda. Of the 32 new cases identified in the last week, 26 have been in Beni.
Beni has been the site of several attacks from Islamist militants based in Uganda, which have terrorized city residents and hindered response operations. Health officials had to pause their response for several days to honor a city-wide period of mourning for those killed in the most violent attacks last month.
The security situation has made response efforts more difficult, said Anne Rimoin, an epidemiologist at the University of California at Los Angeles who researches the Ebola virus and other infectious diseases from Kinshasa.
"Response teams have limited working hours to reduce security risks after dark and must be accompanied by security details," Rimoin said in an email.
The Health Ministry said more than 15,500 people had received a new Ebola vaccine, created in the wake of the 2014-2015 outbreak that killed more than 11,300 people in three impoverished West African nations.
Jessica Ilunga, a spokeswoman for the Congolese Health Ministry, said the new cases of the Ebola virus in Beni were concerning.
"For more than a month now, we have been witnessing an increase in community resistance in the city of Beni. In spite of all our community engagement efforts, some people continue to refuse to collaborate with the response teams," Ilunga said in an email. "All the medical response is in place and well-functioning. So at this point it all comes down to the attitude of the community towards the response."
North Kivu Province has proven an especially difficult area for public health officials to canvass for suspected cases. The province is Congo's most populous outside of Kinshasa, the capital. An estimated 1 million of its 8 million residents are internally displaced people, who have fled from ethnic violence that has riven the eastern part of the country for decades.
Ituri Province, with a population a little more than half that of North Kivu, has also experienced ethnic violence and cross-border attacks from Islamist rebels in Uganda.
Those responding to an outbreak spend the bulk of their time tracking down those who have a virus and figuring out how that virus spread. They then identify those who have had contacts with anyone infected with a virus, in order to quickly begin treating anyone who begins to show symptoms.
Those standard procedures become much more difficult in a situation when virus hunters must worry about their own security, or in cases when populations like internally displaced people move around frequently.
"Identifying all chains of transmission can be difficult given that the local communities in the affected areas are highly mobile and move from village to village for work and family reasons, as well as to seek health care. Access to certain areas is limited due to insecurity to conduct contact tracing," Rimoin said.
An outbreak earlier this year in Équateur Province, along the Congo River, was contained within weeks in a much more stable security situation.
The current epidemic is the 14th known outbreak of the Zaire strain of the Ebola virus, known in epidemiological terms as EBOV. It is the strain with the highest mortality rate; in most outbreaks, more than 60 percent of those who come down with the disease die.