A rare Ebola outbreak in the Democratic Republic of Congo has highlighted significant gaps in disease surveillance, particularly in regions where other common illnesses mask early detection.

A rare Ebola outbreak that may have circulated undetected in northeastern Democratic Republic of Congo for several weeks has exposed the difficulty of detecting deadly viruses in regions where malaria, typhoid and other fever-causing illnesses were common and health systems were stretched thin. About 350 suspected cases and 91 deaths have been reported in northeastern DR Congo, the country’s health minister Roger Kamba said on Sunday, while neighbouring Uganda has confirmed two infections,...