“The things we actually worry about are the horses rather than the zebras,” Dr. James Conway says. Conway, a pediatric infectious disease expert at the University of Wisconsin School of Medicine and Public Health, uses this metaphor to explain that while rare complications — zebras — can occur, it’s important for physicians to first focus on preventing the most common causes of serious illness — the horses. “An ounce of prevention is worth a pound of cure,” Conway adds, noting this cliché is truer than ever in countries like Sudan.