The AIDS virus can be passed from an infected mother to her baby if she pre-chews the child's food as sometimes occurs in developing countries, U.S. government scientists said on Wednesday. The U.S. Centers for Disease Control and Prevention said it had identified three cases -- two in Miami and one in Memphis, Tennessee -- in which a child was infected in this way between 1993 and 2004. The mother was involved in two of the cases and a relative who acted as a caregiver was involved in the third. In developing countries, some mothers pre-chew food for babies. These...