Surprisingly, although one has washed thoroughly, this can cause stains to partners' uniforms or the mat. Nails particularly should be attended to properly. Humans are the greatest health hazards to other humans and a scratch from a dirty fingernail or toenail can result in an infected cut that is slow to heal. In this regard students should be more concerned with transmitting colds and flu to other members than be paranoid about more lethal and exotic diseases. Most cold and flu viruses are transmitted through hand to hand or hand to surface contact.
Bacteria float in the mists of coughs and sneezes.
Your missed work-out is far more acceptable than another's missed work. Some members don't have sick days so if they don't work they don't get paid. An individual who is broke and flat on their back with intestinal distress and body-aches will not be favorably impressed by your samurai spirit which prohibited you from missing a class. Hopefully most of this discussion would seem to be just common sense. Unfortunately, common sense is far too uncommon.