The number of cases in the Ebola outbreak has exceeded 10,000, with 4,922 deaths, the World Health Organization says in its latest report.
Only 27 of the cases have occurred outside the three worst-hit countries, Sierra Leone, Liberia and Guinea.
Those three countries account for all but 10 of the fatalities.
Mali became the latest nation to record a death, a two-year-old girl. More than 40 people known to have come into contact with her have been quarantined.
The latest WHO situation report says that Liberia remains the worst affected country, with 4,665 deaths. Sierra Leone has had 3,896 fatalities and there have been 1,553 in Guinea.
Nigeria has recorded eight deaths and there has been one in Mali and one in the United States.
In the US, the governors of the states of New York and New Jersey have ordered a mandatory 21-day quarantine period for all doctors and other travellers who have had contact with Ebola victims in West Africa.
Anyone arriving from affected West African countries without having had confirmed contact with Ebola victims will be subject to monitoring by public health officials.
The first person to be quarantined under the rules was a female health worker who arrived at Newark Liberty International Airport on Friday.
She had no symptoms then but has since developed a fever and is being monitored.