Chapter 3 - The Timing

Summary

Chapter 3 explores exactly when HIV’s odyssey began – that is, when it made the leap from chimpanzee to human. It reviews the saga of the building of the railway between Brazzaville and the Atlantic Ocean, and the staggering mortality among the thousands of men forced to work on the construction sites. This part of the story features Léon Pales, a clever French surgeon posted in Brazzaville who performed autopsies and identified a new disease eerily similar to AIDS among some of the railway workers. The last few pages of this chapter describe how evolutionary biologists estimated the time when the common ancestor of all HIV-1 strains, the one that infected the very first patient, existed, which was probably in the first two decades of the twentieth century.