Dr. Durvasula e-mailed me back immediately. He couldn’t have been more helpful and concerned—in contrast to the VA staff. We arranged a phone call, and he asked me some questions.

“Does the area have a whitish, pearlescent appearance, surrounded by red?”

“Yes.”

“Does it itch?”

“No.”

“Does it hurt or feel sore at all?”

“No.”

“No discomfort?”

“None at all.”

“Ah, well. I am afraid those are the classic signs of leishmaniasis.”

He asked me to e-mail him a photo. When he got it, he confirmed it certainly appeared to be leish. He suggested I seek help at the National Institutes of Health (NIH), the best place in the world, he said, for leishmaniasis study and treatment.

In the meantime, Dave Yoder explored treatment options in the States. He, too, zeroed in on the National Institutes of Health and contacted them. At the NIH, Dave reached Dr. Thomas Nutman, deputy chief of the Laboratory of Parasitic Diseases. Nutman was fascinated by the story of the expedition to the lost city and the mass outbreak of disease. He wrote Dave:

Dear Dave,

I think there is a very high likelihood that this is Leishmania and because of the strains in Honduras there is a small but real chance that this could turn into mucocutaneous disease depending on the strain… The big issue is defining which strain of Leishmania you have and tailoring treatment to that particular strain… We have taken care of a number of National Geographic folks in the past.

The National Institutes of Health’s overall mission is to “seek fundamental knowledge about the nature and behavior of living systems,” and then leverage that knowledge to “enhance health, lengthen life, and reduce illness and disability.” It is strictly a research institution, and anyone admitted for treatment must be part of a research study. Each of its projects has a set of rules that outline who can be treated, why, and how their treatment will contribute to medical knowledge. If a potential patient meets the criteria and is enrolled, the care is free. It even includes financial help with transportation and lodging. In return, the patient agrees to follow the rules and donate to medical research any tissue samples, cells, blood, parasites, and so forth. A participant can withdraw at any time, for any reason.

The NIH doctors were keenly interested in our situation. The mass outbreak of disease was unusual, the valley of T1 seemed extraordinarily “hot,” and the region was unknown medically, all of which made the expedition an enticing medical study. The doctors offered to treat us all for free. It was nice to be wanted.

In late May, Dave flew from Rome to Washington for a firm diagnosis. “Hopefully,” he joked, “we’ll all turn up negative, and it’ll turn out to be a minor staph infection from Woody’s jungle stew that is easily treated with an application of cayenne sauce.”

The doctor in charge of the project, who would be treating Dave, me, and the other potential “brothers in the leish,” was Theodore Nash, principal investigator in the Clinical Parasitology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases. Nash was one of the country’s leading experts in leishmaniasis treatment, having worked under Dr. Frank Neva, a pioneer in leishmaniasis treatment who came to the NIH from Harvard. After Neva’s retirement, Nash became the chief clinical researcher into leish at the NIH, and over the past decades he advanced its treatment with new drugs and formulations.

At NIH, doctors took a biopsy of Dave’s lesion, looked at it under a microscope, and saw it was teeming with round, microscopic leishmania parasites. But Dave’s treatment would depend on what kind of leish it was. A special lab at NIH began the process of sequencing the parasites’ DNA.

Leishmaniasis has a long and terrible history with human beings, stretching back as far as human records exist and causing suffering and death for thousands of years.

A few years ago, a hundred-million-year-old piece of Burmese amber was found to have trapped a sand fly that had sucked the blood of a reptile, most likely a dinosaur. Inside this sand fly, scientists discovered leishmania parasites, and in its proboscis, or sucking tube, they found reptilian blood cells mingled with the same parasites.

Even dinosaurs got leishmaniasis.

Leishmania has probably been around since the final breakup of the primordial continent known as Pangaea. As these ancient landmasses eventually drifted apart to become the Old and New Worlds, the populations of that sand fly ancestor were separated and continued to evolve independently, eventually giving rise to the two basic strains of the disease in the Old World and the New. At some point the disease made the leap from reptiles to mammals. (Modern reptiles still get leish, and there has been a medical debate over whether reptilian leish can be transmitted to humans; the answer is probably not.)

Unlike many diseases that afflict human beings, leish was global from the very outset, and it was dreaded by our ancient ancestors in both hemispheres. Archaeologists have found leish parasites in Egyptian mummies dating back five thousand years, and in Peruvian mummies going back three thousand years. A description of leish appears in one of the earliest written human documents: the cuneiform tablets of King Ashurbanipal, who ruled the Assyrian Empire 2,700 years ago.

Leishmaniasis comes in three main varieties, each with distinct symptoms.