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.

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

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.