It's actually the opposite JB: It is USUAL to cross from rats to humans (via the rats' excretions such as urine, faeces, saliva) but VERY RARE to cross from humans to humans. There are reports that it has done so on the cruise ship, but with such a long incubation period (can be from 1 to 8 weeks), that may be difficult to be sure at this stage.
It has two main areas of concern: Pulmonary (lungs) and Renal (kidneys). The former is the most lethal with about 35% of infected people dying.
The late Gene Hackman's wife died of a hantavirus infection and her outhouses were found to be rat-infested.
A high fatality rate often means the virus spreads very slowly - but should it become commonly contagious from human to human and at a fast rate, then that is the time we should be worried. But not now (famous last words!).
Cruise ships are famous for Norovirus infections - I've had it (many of you will have also) and its terrible.


Informative x 2