The WHO announced two trials of experimental anti-Ebola drugs to combat the fast-moving outbreak. The US will provide one of the new drugs, a shift in stance after previously saying it would only be available for at-risk Americans.

More than 1,000 cases and 277 deaths have so far been confirmed, most of them in the Democratic Republic of Congo, from the Bundibugyo strain, which has no approved vaccines or treatments.

This Ebola strain may be spreading faster than previous outbreaks because its symptoms are milder, doctors said, with initial data suggesting only 10% of patients develop the extensive bleeding usually associated with the disease — good news for those infected, but potentially making it harder to detect and thus control.