She went to a doctor in January because she had puzzling sores on her hands: inflamed red bumps, a half-inch in diameter, that were firm and hot and hurt when she pressed on them. The doctor prescribed antibiotics. The sores did not go away. Then a second woman came in; then a third, and a fourth. They all had the same sores; some of the nodules had broken open into deep ulcers, and some of the ulcers scored a line up the women’s wrists, as though their forearms had been stitched by a giant sewing machine.

The women were not related, and did not live in the same place, but they had one thing in common: They bought food for their