More than 2,200 have been sickened, according to the UN health agency's latest numbers.
There are quarantines and travel restrictions for the sick and those in contact with them, sometimes including whole villages and counties, but officials warned that the restrictions have sometimes hampered food deliveries.
The UN World Food Programme has said that it is preparing to deliver food to 1 million people over the next three months.
"I think now there is a high vigilance in all countries," Fadela Chaib, a spokeswoman for WHO, told reporters in Geneva.
"I can't remember the last time we fed 1 million people in a quarantine situation."