Africa gives ‘ABC’ mixed grades. AIDS abstinence plan raises awareness but has small effect on behavior.

TORONTO, Aug. 14 — “ABC,” the AIDS-prevention strategy widely promulgated both here and abroad, got a distinctly mixed report card as African countries reported their experiences to delegates at the 16th International AIDS Conference here.

Largess with clear limits: in Africa and elsewhere, Gates Foundation takes focused approach to giving.

KHAYELITSHA, South Africa — Bill and Melinda Gates came to the cramped tin shack of Nkosebaca Thingathinga one day this month to understand how the 61-year-old man had contracted tuberculosis — a major focus of research for the couple’s foundation — an astounding four times.