Dozens of people have died and hundreds have become sick after an unknown illness appeared in Congo’s northwestern Equateur province, WHO spokesperson Tarik Jasarevic said Tuesday during a UN briefing.

More than 50 people have died in two clusters of unknown illnesses in northwest Congo, global health authorities said.

An unknown illness first discovered in three children who ate a bat has rapidly killed more than 50 people in northwestern Congo over the past five weeks, health experts say.