An outbreak of an unknown illness is currently occurring in the Democratic Republic of the Congo. The illness is characterized by rapid onset of symptoms and death within hours or days. Initial tests have ruled out Ebola and Marburg, but the cause remains unknown. - More than 50 people have died from a mysterious illness in northwestern Congo. - The World Health Organization and local health authorities are investigating the outbreak to determine the cause. - The illness is characterized by a rapid progression, with death occurring within hours or days of symptom onset. - Initial reports suggest a possible link to three children who consumed a bat carcass before falling ill. - Over 400 cases have been recorded since January.