In an op-ed article published in The Washington Post, Mr. Bush, in a rare injection into the public sphere, called the advancements in AIDS treatments "remarkable."
"It is proof of what many in Africa call the Lazarus effect: Communities once given up for dead have been brought back to life, and millions of men, women and children are alive to build their futures," he wrote.
The 43rd president attributed the Global Fund to Fight AIDS, Malaria and Tuberculosis and its predecessor, the President's Emergency Plan for AIDS Relief (PEPFAR), for providing 6.2 million people in sub-Saharan Africa with antiviral drugs. PEPFAR, however, is not without its critics, including those who oppose the program's focus on abstinence to prevent the spread of HIV/AIDS.
"It would be a sad and terrible thing if the world chose this moment to lose its focus and will. Other countries and local governments in Africa can do more in providing resources and increasing funding -- as the new government of Zambia is doing. But to continue the momentum in the fight against AIDS, America must continue to lead," Mr. Bush wrote.
In his op-ed, the former president also called on the U.S. government to use the success of AIDS treatment to expand care for other diseases impacting Africans, including breast and cervical cancer, through his and Laura Bush's organization, Pink Ribbon Red Ribbon.
"It is heart-wrenching to save a woman from AIDS, only to watch her die from cervical cancer, which is more prevalent in women with HIV," he wrote, saying those are two of the leading causes of death in Africa.
Meanwhile, a gathering of more than 25,000 people is taking place this week in Washington, D.C., to take stock of accomplishments and challenges ahead in the battle against AIDS. It is the first time in its 19-year history that the International AIDS Conference is taking place in the U.S. The six-day event features speeches by former President Bill Clinton, Secretary of State Hillary Clinton, United Nations Secretary General Ban Ki-moon and actress Sharon Stone.