I have the same opinion like arne_bab.

Its a huge difference if a virus is spread by criminals or by the state.
And if a state does this its clearly oppression.

I think for such crime acts (made by states) there are several international criminal courts who can process they, but it has to be brought to justice by a government or an organization. Maybe with a petition or somethink similar.

By the way, arne_bab your example with the landmines and virusses is very good, i have to note this ; )