"That year Richer launched a counter offensive, hoping to fight back the parasite at least in Tambura county. For people who were still in the early stages of the disease *, ten days of injections in the buttocks with the drug pentamidine was enough. For those like Justin who had the parasites in their brains, a harsher course was necessary. They needed stronger stuff that could kill the parasite outright in their brain— a brutal potion known as melarsoprol. Melarsoprol is made of 20 percent arsenic. It can melt ordinary plastic IV tubes, so Richer had to have tubes flown in that were as tough as Teflon. If melarsoprol seeps out of a vein, it can turn the surrounding flesh into a swollen, painful mass; then, at the very least the drugs have to be stopped for a few days, and at worst the arm may have to be amputated."
* sleeping sickness