(CNN) -- The young man's call echoed throughout the remote village in northern Nigeria -- the marriage ceremony was about to begin. Umar Ahmed and his wife wait for anti-HIV drugs at a hospital in Nigeria. Under the dusty sun, the fathers of the bride and groom agreed to the marriage and this ancient Muslim tradition proceeded as it has for hundreds of years. But unknown to the gathered villagers, the couple is hiding a modern secret. Both bride and groom are HIV-positive and marrying with the support of a local government program that encourages such "HIV-marriages" in the hope of preventing the virus from spreading.
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Local agency will pay dowry, offer counseling, to get HIV-positive couples to wed
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The goal is to keep HIV from spreading to people not already infected
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UN agency says marriage doesn't stop AIDS, prevention and treatment needed
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For some couples, the marriages reduce stigma of being HIV-positive
According to the United Nations, Nigeria has the third-largest @placeholder population in the world, with about 3.1 percent of its 148 million people infected.