AS A middle-class Senegalese man, Salou (not his real name) was rather proud of his roundness in 2002. But by 2003 his clothes were falling off. He got tested and found he had AIDS. His pregnant wife was also infected with HIV. They went to Dakar, Senegal’s capital, and she was put on antiretroviral drugs to prevent the infection of her unborn child. “When my son was born he tested negative, thank God,” exclaimed Salou.

The hopeful tale of Salou’s baby is far from universal. Although west and central Africa have long had a lower prevalence of HIV than the south and east (see map), the region still has a stubbornly high rate of new infections. In south and east Africa close on 20m people have the virus, almost four times more than in west and central Africa. From this high base, the number of new infections each year in the south and east has fallen by 29% since 2010, to 790,000. Alas, new infections in west and central Africa have fallen just 9%, to 370,000. Moreover, about 310,000 people die from HIV-related illnesses each year in west and central Africa, compared with 420,000 a year in east and southern Africa. This high toll is prompting urgent calls from global bodies such as UNAIDS and UNICEF for a new approach.

An example of that may be found in Senegal, which has cut new infections by almost three-quarters since 2010, leaving it with one of the least-afflicted populations in Africa. Whereas 4.3% of people in sub-Saharan Africa are HIV-positive, the prevalence in Senegal is just 0.4%.

Senegal may be poor but its HIV prevention and treatment system punches above its weight. It was the first country in sub-Saharan Africa to start a government-backed programme to treat people with antiretrovirals in 1998, not just prolonging the lives of those with HIV but reducing the chances that they would pass it on. In a bold move in 2003 it made the treatment free, several years before the World Health Organisation recommended that countries do so.

It has also pushed back social taboos by ensuring that drug users and sex workers are treated. Prostitution is legal in Senegal, so long as sex workers have health check-ups every three months. If they get HIV, they are not driven underground, where they might continue to spread the disease. Instead they are allowed to work while being given free treatment, which makes them less infectious. As a result, HIV prevalence among sex workers dropped from 28% in 2002 to 7% in 2016, according to UNAIDS. Drug users are given free syringes, so they are less tempted to use dirty ones.

Senegal’s decentralised health-care system helps, says Ibrahima Traoré of the Social Polytechnic Institute of Hygiene in Dakar. The number of sites offering voluntary counselling and testing increased by 600% in the four years to 2010.

One thing that Senegal has done remarkably well is to involve a wide range of groups in tackling the virus. Marabouts (imams) talk about HIV in mosques. Women’s groups try to find unregulated sex workers and Senegal’s famous wrestling groups teach men about the risks of unsafe sex. This use of civil society is something that is sorely lacking elsewhere in the region, says Nathalie Cartier of Médecins Sans Frontières.

To be sure, there is work to be done. About half of people infected with HIV are still not being treated. Only about a quarter of children with the virus are getting medication for it. And gay men are afraid to ask for advice because homosexuality is punishable by up to five years in jail. Nonetheless, Senegal has shown that even a poor country can curb the epidemic.