[kadoban]

Probably safer to hug them than another human. Most diseases don't even cross species boundaries, seems unlikely they'd do well trying to infect a completely alien being.

The reason that diseases from the old world were so deadly, when they crossed the pond, is that they'd evolved to spread quite well even in humans with an evolved or acquired resistance and were suddenly in a completely unprepared population.

[api]

The danger would be organisms that simply eat our biochemistry but are entirely immune to any of our defenses. Think flesh eating bacteria from space, only it also basically eats our entire biosphere.