Perhaps you've misunderstood. ILI, influenza-like illness, respiratory infection. Apples and apples. Coronaviruses have been known as one of the agents of the common cold for better than a half century. I'm not supporting the position of communal or familial responsibility, though those things are not at all unknown in Japan and the sumo world. I was wondering more generally how the NSK and all its members got by in past pandemics. How did the organisation survive? How did they manage tournaments and jungyo and training in all of that? Is it known that they punished heya with infections collectively? That rikishi dropped down the banzuke? There were no PCR tests in those days. They had to rely on symptoms. Nobody could be excluded for a dubious test. Some historical context would be extremely interesting and informative...