Health officials in Mali have identified 111 people who came into contact with the nation's first Ebola patient last week, according to an internal World Health Organisation document.

Workers have been unable to find at least 40 of those people who may have been exposed to the toddler, the Geneva-based organisation said in the document. The two-year-old girl contracted the disease in Guinea and died on October 25 in Mali.

Suited up: Health workers at an Ebola treatment centre in Mali. Credit:AP

Mali's government is working with the Red Cross and Medecins Sans Frontieres to limit the spread of the disease, which has already killed about 5000 people in Guinea, Liberia and Sierra Leone since March. Mali's weak health system will make it harder to track those exposed and isolate them, said the Red Cross.

In the US, federal health officials on Monday revamped guidelines for doctors and nurses returning to the US from treating Ebola patients in West Africa, stopping well short of controversial mandatory quarantines being imposed by some US states.