Forty-one people have died in the latest outbreak of Ebola in DR Congo, health authorities said on Tuesday, adding that doctors were using a novel drug to treat patients.

Out of 57 recorded cases as of Monday, 41 were fatal, the Congolese Health Ministry and UN’s World Health Organization (WHO) said. Fourteen of the deaths had been confirmed by lab tests, the ministry said.

Last Friday, the ministry put the tally at 37 deaths, either confirmed or suspected.