Public health officials in Africa urged caution Thursday as Congo’s health minister said the government was on alert over a mystery flu-like disease that in recent weeks killed dozens of people.

“First diagnostics are leading us to think it is a respiratory disease,” said Jean Kaseya,  the head of Africa Centers for Disease Control and Prevention. “But we need to wait for the laboratory results.”

He added that there are many things that are still unknown about the disease — including whether it is infectious and how it is transmitted.

Authorities in Congo have so far confirmed 71 deaths, including 27 people who died in hospitals and 44 in the community in the southern Kwango province.