Sir Francis Drake died of dysentery while attacking the town of San Juan in Puerto Rico. He was buried at sea in a lead coffin. Henry V succumbed to it at 35. Accounts of the African missionary explorer David Livingstone’s lingering death from dysentery make grim reading. Near the end he was too weak to hold a pencil. He was found dead on his knees in prayer. Tough guy Ernest Hemingway had so many bowel movements in a short time he suffered a prolapse and afterwards went into a physical and mental decline. In Africa it is said to kill hundreds of thousands of children under five annually.

The first time I had dysentery, I had the watery, Shigellosis version. It visited me on a three-day hike up Mount Kilimanjaro in Tanzania. Dysentery is inconvenient, apart from anything else. I ran out of toilet paper almost immediately and resorted afterwards to chapters torn from a paperback thriller, leaves and, above the tree line, smooth stones. My first week in Africa. I’d been on a derailed train and now this.

We were a party of 22, plus porters and a guide. During the afternoon of the second day my difficulties were compounded by altitude sickness and I fell behind. Each step took the whole of my strength and willpower to accomplish. In a weird volcanic landscape ominously dotted with small cairns, I gave up, lay down on my back, and ‘half in love with easeful death’ closed my eyes, and drifted pleasantly away.

Presently I heard voices and the approaching footsteps on the gravel of another party of hikers. Scandinavians, I think they were. Too weak to open my eyes, I heard them crowding around to have a closer look at the corpse. Titters. Someone made a joke. Laughter. Then the clicking and whirring of camera shutters held close to my face. Another witty comment. More laughter. Then they moved off, and the sound of gravelly footsteps and lighthearted conversation receded into silence.

I was rescued by the guide, who returned and assisted me back down the mountainside. Our party was travelling west in a Bedford truck. After Kilimanjaro we visited the spectacular Ngorongoro Crater and game reserve. I spent most of the time squatting in the bushes. It became a way of life. As our group assigned unspoken roles to its constituent members, I found an early niche as the invalid with his trousers down. In camp, they always knew where to find me. During their forays on to the caldera floor to observe the big five, I was left behind with an armed guard and some tissues. While their daily perspectives across that vast landscape were immense, mine were always the nearer ones of leaves, grass stems, suspended spiders and the fascinating insect life of the undergrowth.

It was here in the Ngorongoro Crater bushes, when I thought that things couldn’t get any worse, that they did. One morning my searching, horrified fingers came upon an unexpected deformity, a growing mass beneath the skin, which had the makings of a gigantic perianal abscess. And right at that moment something forceful came crashing through the undergrowth, and an elephant with bloody great tusks passed by not ten feet away from where I was squatting, followed by a dozen others in single file. Perhaps they quickly and astutely perceived that a man in my position posed only the most negligible of threats, because they paid me little or no attention.

From the Ngorongoro Crater we drove across the Serengeti, while my abscess took shape and ripened. My travelling companions sat in two inward-facing rows in the back of the truck, every one of them in rude health, cheerful and invigorated by the outdoor life. Visibly thinner by the day, I knelt on the hard floor between them, grimacing, and occasionally whimpering in agony as we jolted over a pothole.

Our driver and tour leader was a muscle-bound Pom-hating surfie from Perth in Australia. He was so tough, he’d walked up Kilimanjaro in his bare feet and wearing only a tiny pair of bathers. I must stop whinging, was his advice. It was probably nothing and would heal itself. These things always seem worse than they actually are — especially to Poms.

One evening we had camped in the Serengeti and the pain was becoming unbearable. I petitioned the Perth surfie to somehow get a doctor to me. ‘All right,’ he said, exasperatedly, ‘let’s have a look.’ We walked to the edge of the campsite and I pulled down my shorts and bent over. He peered. ‘Mate,’ he said. ‘Can you part your cheeks a bit?’ I did so. There was a stunned silence. Then he said excitedly, ‘Mate, can you hold it right there for a second? I’m just going to fetch my camera. I’ve got to get a shot of that to show me mates back home.’