They carried ornate spears and small wooden stools, and their cattle, their only means of subsistence, milled around us. They watched transfixed but inscrutable as we strange white aliens busied ourselves under the only shady tree for miles. In the saturating heat we purposefully erected our make-shift hospital using bed sheets, wire, gazebos, pasting tables and treatment couches.

My lingering doubts evaporated as we transformed this lonely tree into a fully functioning medical centre with two doctors, a dentist, a radiologist, a pharmacist, two osteopaths and three nurses. This was Blue Peter-style medicine, relying heavily on the ingenious use of scarce resources. After a few hours of problem-solving, we had conjured a safe and operable medical environment from the parched sand. We worked solidly and conscientiously through the sweltering day, urgently trying to treat all those who had come. Some had walked 30 miles that morning to see us.

We repeated this routine in a new location every morning for 10 days. It was both miraculous and exhausting.