MEXICO CITY: The world must continue to strive for better containment of HIV/AIDS and increase its fight against discrimination, delegates to the 17th International AIDS Conference (IAS), which opened here on Sunday, were told.

"This epidemic, the most complex, the most challenging and probably the most demanding infectious disease humanity has ever had to face, is far from over," Margaret Chan, director-general of the World Health Organization said at the opening session of the six-day event.

"We dare not let down our guard. This is an unforgiving epidemic," she said.