But when the 29-year-old arrived at the airport in Miami, he made no such disclosure to the American Airlines agents checking him in, instead presenting a medical certificate that said he was fit to fly. It was only the following day, when he landed in Buenos Aires and health officials took his temperature, finding he had a fever of 101.3 degrees, that he made his confession: He probably had covid-19 — and should not have boarded the plane to begin with. “Due to this irresponsible, selfish behavior, 200 people are at risk despite having done the right thing while traveling,” Florencia Carignano, Argentina’s top immigration official, told reporters this week.