In West Africa, authorities raced to contain the Ebola virus amid news that another Christian missionary, a Spanish priest, was infected. The priest was airlifted to Madrid. The World Health Organization said it would convene a group of medical ethicists next week to discuss whether experimental drugs, including the serum used on the two infected American missionaries, should be given to others who have contracted the virus. The serum had not yet been tested on humans, but there are no other approved and effective treatments for Ebola.