Health officials fear the Ebola virus behind a massive outbreak in the Democratic Republic of the Congo (DRC) could be mutating, as confirmed cases pass 4,000.
Africa's public health watchdog said the time for incremental action was over, announcing plans to scale up every aspect of the response and go "door to door" looking for patients.
Unprecedented Severity
The Ebola outbreak, caused by the Bundibugyo strain, was first reported on 15 May, though suspicions suggest the disease may have been spreading since January.
As of 4 August, there have been 3,973 cases and 1,801 deaths, according to the DRC's national public health institute. On Thursday, Dr Jean Kaseya, director general of the Africa Centres for Disease Control and Prevention (Africa CDC), told a press briefing cases had topped 4,000.
The outbreak is now the second-largest on record, with eight times more cases and six times more deaths than were recorded 11 weeks into the West Africa Ebola outbreak of 2014-18, which infected over 28,000 people and killed at least 11,000.
Concerns of Mutation
Kaseya said he had spoken to the WHO director general, Dr Tedros Adhanom Ghebreyesus, and they planned studies "to check if there is no additional issue, or maybe if the virus is not mutating. Because the level of severity of this Bundibugyo outbreak is unprecedented."
More than two-thirds of Ebola deaths are occurring in the community rather than in treatment centres. In an MSF-run centre in Bunia, capital of Ituri province, 90% of admitted patients do not appear on authorities' lists of contacts of known cases, indicating high levels of untracked transmission.
Kaseya said contact tracing in the DRC was insufficient, with only 10 contacts identified per Ebola patient, compared with an expected 40.
Scaling Up Response
Dr Wessam Mankoula, acting head of emergency preparedness and response at Africa CDC, said response teams planned a shift "from contact tracing to active case search," with community health workers "moving from door to door" asking households if anyone had Ebola symptoms. He added: "I think the time for incremental action is over and we're starting now the phase for scaling up."
Kaseya promised a "village-centered response" involving communities, more use of digital tools, and greater action in camps for internally displaced people in affected provinces.
Officials also plan to use antiviral remdesivir on a compassionate use basis and to test whether the Ervebo vaccine, licensed against a different Ebola strain, should be offered in the affected province after data suggested Bundibugyo caused less serious disease and "zero death" among those vaccinated.
"Seeing the expansion of this outbreak, only the public health measure will not be enough to quickly control or stop this outbreak," said Dr Placide Mbala Kingebeni, Africa CDC director of research, clinical trials and innovation.
DRC authorities are investigating a suspected Ebola death on a boat heading to Kinshasa from the north-east; other passengers will be quarantined and tested.
Unicef warned that essential healthcare was being disrupted, with fear of infection keeping families away from clinics. In Mongbwalu, the outbreak's centre, the proportion of children receiving their first measles dose has fallen 69%.
