NAIROBI, Kenya — A Trump administration order took effect this week barring US aid for global health organizations that discuss or provide referrals for abortion. But the new policy put another program in the crosshairs: America’s global HIV/AIDS effort.

Since 2003, the US government has spent more than $70 billion to combat the global epidemic, with tremendous results. The annual number of AIDS-related deaths has fallen by more than 40 percent. Under President Trump’s expansion of the so-called global gag rule, however, many HIV/AIDS organizations funded by the United States stand to lose their funding, putting at risk the possibility of eliminating the epidemic by 2030, a commitment established at the UN General Assembly last year. About $6 billion in US HIV/AIDS funding could be affected.

‘‘Reaching those ambitious targets could now be placed in real jeopardy,’’ said Divya Bajpai, the director of programs at the International HIV/AIDS Alliance.

HIV/AIDS organizations could lose their US funding not because they provide abortions, but because they offer counseling that includes the mention of abortion, or a referral to an abortion provider.

The health organizations — most of which are in Africa, the region most affected by AIDS — will be able to keep their US assistance only if they agree not to mention abortion services to their patients.

Past Republican presidents implemented versions of the global ‘‘gag rule,’’ but they affected only about $600 million in family-planning funds and did not apply to groups fighting HIV/AIDS. President George W. Bush, whose administration launched the multibillion-dollar President’s Emergency Plan for AIDS Relief (PEPFAR), is credited across much of Africa for his role in tackling the epidemic.

The International HIV/AIDS Alliance, which consists of 32 local organizations, offers a window into how the new policy will play out. The alliance receives a total of $130 million in annual funding — 20 percent of which comes from the United States. Each of the alliance’s members will now have to decide whether to keep its US assistance by cutting any mention of abortion from its services.

‘‘This is going to drive girls and young women away from treatment,’’ said Bajpai.

Thanks in large part to US funding, hundreds of community health organizations treating HIV/AIDS have emerged across the developing world. Many of them, such as Family Health Options Kenya, offer a range of services, from antiretroviral treatment to contraceptive distribution and abortion counseling.

Experts say Trump’s policy could especially affect girls and young women, who are now the most likely people to contract the disease.

‘‘Girls and young women account for 74 percent of new HIV infections among adolescents in sub-Saharan Africa,’’ according to PEPFAR’s fact sheet.

Some of those girls and young women contract the disease after a violent sexual encounter, which in some cases also results in an unwanted pregnancy.

A recent United Nations study said that in some regions, women who had experienced physical or sexual abuse by their partners were 1.5 times more likely to acquire the disease than those who had not.