You need to be able to distinguish between a country’s primary mode of production versus the scope of its total. A “perfect” capitalist or communist one will likely never exist, at least not any time soon. You cannot ignore the aspects of the basis on which development happens.
Every mode of production contains elements of its former, according to Marx, exactly because we have to understand human development and our current paradigm through historical materialism.
To say that a communist nation cannot contain capitalist components as its non fundamental mode of production is as stupid as saying Britain is not capitalist because they have a king.
No, but they get some nasty stuff that if transmitted to humans more often prove lethal. It is due to bats having an incredibly high body temperature (even more so than most other flying things though most of them are high). Human fever really cannot compete with that and our bodies may just kill themselves with the viral response IIRC.