An agreeable, totally un-Ratched nurse arrived, inserted the IV, and drew blood; then she started me on the saline drip. My actual ulcer would not be messed with, although they would examine it every day to see if it began to heal.

The bloodwork came back an hour later and all was good: I had strong kidney function. With both Drs. Nash and O’Connell in watchful attendance, the evil brown bag of amphotericin B was hung on the IV rack next to a bag of Benadryl. Fifteen minutes of a Benadryl infusion left me feeling groggy, and then the stopcock was turned and the ampho started down the tubes.

Dave, our honorary Italian, had compared it to limoncello. To me it looked like the color of urine. Watching it creep down the tube toward my vein only raised my anxiety levels, so I forced myself to avert my eyes. I chatted with the doctors and my wife, pretending nothing was happening, but all the while bracing myself for the sudden pain, the pressure, my head erupting in flames, God, or Baal. I could see my two doctors were also chatting about nothing with excessive cheer, trying to cover up their own nervousness.

The yellow liquid went in and then—nothing happened. I experienced none of the side effects that Dave and Chris did. It was a total anticlimax. Everyone was relieved, but I was also slightly disappointed.

From there, my treatment proceeded uneventfully. I arrived at the clinical center every morning around eight, got stuck with an IV, was subjected to a battery of blood tests, and then infused. After the third day, I asked my doctors to stop the Benadryl (aimed at blocking an allergic reaction to the drug) because it made me sleepy. They did so with no problems. After a few days the inevitable nasty side effects of the ampho did begin to creep in: I got a persistent headache and started to feel nauseated. Beyond that, I had a vague mental uneasiness that something was going badly wrong inside me, but I couldn’t put my finger on what. The side effects worsened until the sixth day, when I felt I was dragging around the world’s worst hangover—headache, nausea, lethargy, and muddled thinking. Toward the end of my treatment, Mark Adams, the sound engineer, started his. Mark had been on both expeditions, the 2012 lidar search and the 2015 jungle foray. He had been one of my favorite people, soft-spoken and cheerful even while hauling forty pounds of sound equipment and a long boom mic through dense jungle in the pouring rain. We asked to be together in the same room, where we passed the time chatting and reminiscing about our adventures. Mark also tolerated the ampho well, experiencing none of the scary side effects.

Awful as I felt, the nausea and apathy were among the most common and mildest side effects of amphotericin. I was extremely lucky. My doctors gave me anti-nausea drugs, ibuprofen, and a vile-tasting drink to restore my electrolyte balance. But on the sixth day, Nash and O’Connell told me my kidney function had dropped into the danger zone and they were going to discontinue the infusions. They wanted me to wait and have the final infusion after my kidneys had recovered. I received that infusion a few weeks later, closer to home, arranged by the NIH and my brother David, who is a doctor.

The hangover went away after about a week of the initial round, and in the following months the lesion dried up, flattened out, and turned into a shiny scar. At one point I asked Dr. Nash about the risks of going back into the jungle, which, despite everything, part of me remained eager to do if I could. He said that research indicated that 75 to 85 percent of people who got leish were thereafter immune; he felt I should be much more concerned about other diseases rife in the area for which there are no preventatives—dengue fever, chikungunya, and Chagas’ disease. (At this point Zika had not yet arrived in Honduras.)

I returned to the NIH three months later, in September 2015, for a follow-up. Nash and O’Connell looked me over, poked at the scar, took some blood, and concluded that the disease had been drubbed into remission. I was cured, at least as far as was possible. While neither doctor could talk about the other members of the expedition due to medical confidentially, I did learn that I was one of the lucky ones, and that some of my fellow travelers (who have asked me not to identify them) have not been cured and require additional courses of treatment using miltefosine or other drugs. Some are still struggling with the disease. (Unfortunately, at the time of this writing, my own leish appears to be returning, although I haven’t told my doctors yet.)

Meanwhile, I had become curious about the NIH’s leishmania research, said to be the most advanced in the world. I wondered what their scientists had learned, if anything, from studying our particular parasite. So I took the opportunity to pay a visit to the leishmania laboratory on the campus, where researchers maintain a live colony of infected sand flies and mice. It is one of the few laboratories in the world breeding and raising infected sand flies—a tricky and dangerous business.

The leish lab is officially called the Intracellular Parasite Biology Section. It keeps a biological archive of live leishmania parasites of many different strains and species, some going back decades. The parasites are cultivated from biopsied tissue samples taken from people like me. These bits of tissue are placed on a blood agar plate, where the parasites are teased into multiplying. Then they are transferred into bottles filled with a liquid nourishing medium and stored at seventy-seven degrees, the body temperature of the sand fly. In the bottles, the parasites go about their business, fooled into thinking they are swimming around inside the gut of a host fly.

The sand fly has a much lower body temperature than human beings. Cutaneous and mucosal leish parasites do not like the higher heat of the human body; that is why they normally remain on the skin or seek out the mouth and nasal membranes, where the body temperature is a few degrees lower. (This is not true of visceral leish, which tolerates heat and goes deep into the body.)