Roughly a quarter of Ebola infections in eastern Congo are estimated to be going undetected or found too late, a World Health Organization (WHO) expert said on Thursday.
Some 2,025 cases and 1,357 deaths have been recorded since the epidemic began in August in the Democratic Republic of the Congo's North Kivu and Ituri provinces, said Dr Mike Ryan, executive director of WHO's Health Emergencies Programme.
It is the second-worst outbreak of the virus on record.
Some 88 infections have been detected each of the last two weeks, down from a peak of 126 weekly in April, and WHO teams are following up on 15,000 suspected contacts each day, a "huge number" who require checking for symptoms, he added.
"We believe, let me be very cautious here, we believe we are probably detecting in excess of 75 percent of cases – we may be missing up to a quarter of cases," Ryan told a news briefing in Geneva.
There were "a lot of cases with very delayed detection," he added. "We must get earlier detection of cases, have more exhaustive identification of cases."
The epidemic was not under control, he said, and was spreading fast in the rural area of Mabalako.
Risks posed by insurgents
Ryan said risks to aid workers had decreased of late but noted a deadly attack on civilians earlier this week.
A local official said 13 civilians were killed late on Monday in an attack by the Allied Democratic Forces (ADF) – a group thought to be linked to Daesh.
Greater political engagement is needed to combat the Ebola outbreak, Ryan said.
"We need the government to reach out to the opposition, we need an 'all party' approach ... we need a single voice of leaders in Congo about this outbreak."