Morocco’s Marathon des Sables is famously challenging, covering 155 miles of Saharan dunes. This year, dropouts reached an all-time high, and a runner died as temperatures soared and an unidentified disease ravaged the field. After the race, some participants complained about inadequate medical support.
On Oct. 3, 753 runners took off over the sand at the Marathon des Sables. Five days and 155 miles later, just 353 would cut the tape at the finish line. Of the 400 runners who did not finish, one man, an experienced ultrarunner in his 50s, died.
Moroccan brothers Rachid and Mohamed El Morabity took first and second overall, by wide margins. But Rachid’s win, his eighth of the iconic sand race in its 35-year history, seemed like a bullet point. The event usually results in low DNF numbers, which is thought to be due to its long cutoff times and robust support system.
So why did so many runners drop out in 2021?
DNF Factors: Nasty Stomach Bug, Soaring Temps
Of all the factors that made the 2021 Marathon des Sables (MdS) historically challenging, a mysterious stomach bug might have been the most potent. The “D&V”-inducing disease knocked out both competitors and medical staff, leading to a situation in the camp that some have called a “warzone.”
Ian Corless, who’s attended seven Marathons des Sables as a photographer, experienced it first-hand. Corless reported that the sickness surfaced almost immediately and spread through the field quickly. By day three, he had it himself.
“One thing is for sure, the sickness when it came was brutal and debilitating,” he wrote on his personal blog. “I got it on the evening of day 3 at 2000hrs and without going into too much detail was losing fluids from both ends for 6-7 hours.”
Event medical staff still hasn’t released quantitative information about the disease itself. For now, what it was and how many people got it is unknown.
Of course, significant fluid loss means big problems for any endurance athlete, especially in hot weather. By its nature, the Marathon des Sables is a race that demands heat tolerance — by many accounts, this year’s edition required more than usual.
Are the Safety Margins at the 2021 Marathon des Sables Enough?

Context: What Does Medical Care at the Marathon des Sables Look Like?
