Sammy--Diamond Princess is the only ship that for sure had Corona onboard. The other ship, the Westerdam, which supposedly had someone onboard with Corona, the lady tested positive and then negative, so it may have been a false positive, which apparently happens. I think that is the biggest problem so far with this thing, that the test is apparently not very accurate, as there are several instances of negative and then positive AND the opposite, within close proximity in time. And perhaps an even bigger problem, a substantial portion of the people infected are asymptomatic, as in, NO symptoms. So they don't have any idea they have been infected. Ships are not really the biggest risk. It is people, travelling on planes. The Diamond Princess situation supposedly all started from ONE person who was infected, although I kind of wonder about that chronology now. Immigration officials can check for people who have recently been in China, but small cells are popping up everywhere now, such as in Italy. A tourist destination cannot stop everyone from coming in.

"Also, this type of virus should not spread as aggressively in warmer and more humid environments." Really? Where did you get that from?