During the past 25 years, AIDS has spread throughout the world. The first cases of AIDS were reported in 1981. Since then, the disease has become a pandemic. Now there are nearly 40 million people infected with HIV, the virus that causes AIDS.

Africa is the hardest-hit continent. More than 60 percent of all the people in the world with HIV live there. But no region has been spared.

Why does the author conclude the article with this passage?

to contrast current events with past events
to place a spotlight on the African continent
to place emphasis on what is happening now
to compare AIDS to diseases mentioned earlier