Ebola reaches Congo's Sud-Ubangi after a patient crossed Rwanda and Uganda

An Ebola case has been confirmed in Sud-Ubangi, a north-western province of the Democratic Republic of Congo that borders the Central African Republic and the Republic of Congo. Acting governor Jean-Rene Galekwa Vundawe said laboratory tests on a sample from the Bulu health district found Bundibugyo ebolavirus. Jean-Jacques Muyembe, head of the National Institute for Biomedical Research in Kinshasa, confirmed the result on Friday.

Jean-Jacques Mbungani, a former health minister and a lawmaker from the area, said the patient was a 23-year-old man who died on Tuesday in the town of Gwaka. In about three weeks the man had left Kamanyola in South Kivu, passed through Rwanda and Uganda, re-entered Congo through Aru and Bunia in Ituri, then travelled west through Kisangani, Bumba, Lisala and Akula before reaching Gwaka. Galekwa said symptoms appeared in Kisangani and that the last stretch was by boat on the Congo River.

Thirty-eight people who had contact with the patient are in quarantine. Local transmission in Sud-Ubangi has not been confirmed, so the province is not yet on the official list of affected provinces. If secondary cases appear, it will be the seventh province in this outbreak and the first in the west of the country. Galekwa warned that the river and road route exposes North-Ubangi, Tshopo and Mongala.

Government figures through Wednesday listed 6,942 cases and 3,349 deaths since the outbreak was confirmed in mid-May. That death count already exceeds the 2,299 deaths in Congo's 2018-2020 epidemic, previously the country's worst. It is Congo's 17th outbreak and the second-largest on record after the 2014-2016 West Africa epidemic, which killed more than 11,300 people. The World Health Organization has said the current wave remains out of control and could pass that West African mark.

Bundibugyo is a rarer species of ebolavirus than the Zaire strain that drove most previous Congolese epidemics. It still kills through vomiting, diarrhoea, shock and organ failure. Almost half of the confirmed cases in this outbreak have been fatal. Vaccines and treatments used against Zaire ebolavirus are not a simple match for Bundibugyo, which is one reason health teams have struggled to blunt the curve.

The geography is the new problem. Until this week the epidemic sat in the east, across dozens of health zones in six provinces. Sud-Ubangi opens a corridor toward Brazzaville and Bangui. A patient who used both road and river transport for three weeks leaves a contact list that is long and hard to reconstruct. Mbungani said neighbouring provinces and countries are at risk for that reason.

Congo's response machine has been built around eastern roads, eastern treatment centres and eastern community networks. Moving kits, teams and safe-burial units to Gwaka takes time the virus does not offer. The 38 quarantined contacts are the first test of whether western health zones can find people faster than the incubation period runs out.

The official stance that Sud-Ubangi is not yet an affected province is a classification, not a comfort. A confirmed death, a positive laboratory result and a three-week itinerary through two foreign countries and half of Congo are already enough to force screening at river ports and at the CAR and Congo-Brazzaville borders. Whether that screening appears this weekend will say more than the classification will.