There are no vaccines or treatments for the strain of Ebola that has killed more than 200 people in the Congo and Uganda, but several are being urgently developed in the hope of reining in the outbreak.

More than 875 cases of the Bundibugyo strain?have been confirmed, including 202 deaths, in a little over a month, the African Union¡¯s health agency said on Thursday.

However, the true scale of the outbreak remains unknown, humanitarian organizations have warned, because the virus could still be spreading in remote, poor and conflict-wracked areas of the?Congo.