U.S. doctor tests positive for Ebola virus

A doctor has tested positive for the Ebola virus in New York. The doctor returned to the U.S. from treating Ebola patients in West Africa over a week ago. This is the fourth confirmed case of the virus in the United States. The 33-year-old emergency room doctor said he had rode a subway and been at a bowling alley before he started showing symptoms. Four people who have been in contact with the doctor are now in quarantine.