Unnamed doctor was working in missionary group in Liberia
                                
                                
                                    (Newser) -
                                    A second American doctor working in Liberia has tested positive for Ebola, missionary group Serving in Mission USA is confirming, as per  the AP . It's not clear how the doctor, who was not named, contracted the virus: He was working in an obstetrics unit in a Monrovia hospital, and...