An American doctor and his colleague have joined the nearly 1,100 people who have become infected by the Ebola virus in an outbreak that has claimed 660 lives in West Africa. Health officials say it is the worst outbreak of the virus ever recorded. Dr. Kent Brantly and Nancy Writebol, who were both working with the Christian aid group Samaritan’s Purse, are receiving treatment for the virus they contracted while treating patients in Liberia. The group says that both of the aid workers were taking extreme caution while working with Serving in Mission—a collaborative treatment project between Samaritan’s Purse and the local ELWA Hospital. Both are currently receiving treatment for the potentially deadly virus …