Entitled, “Brown Eye Blue”, this picture was captured in a remote village, in rural Chad, along the Chari River, while conducting a study with the Carter Center, and the World Health Organization (WHO). The study focused on Guinea Worm disease (GWD), or dracunculiasis, the next disease after smallpox, slated for global eradication. GWD is rare, with only three remaining human cases left in the world, as of March 2018. The photographer was interviewing this woman about her son, who was infected with Guinea worm, a few years prior, when she noticed her eyes were different colors, a condition known as heterochromia. Another prominent feature on her face, were the scarification markings, unique to the Sara people. Her son was one of the last remaining human cases in the world. Unseen here, his eyes are both blue a recessive trait almost as rare, as Guinea worm itself.