We planetary protection directives, you know.
Honestly, after seeing those anti-corruption rule books - and on the same homepages where they are displayed, the markers in countrys where you cant to buisness without - sort a contamination scenario in itself, i doubt that anything can prevent this once the dice with the one killing side gets re rolled often enough.
So my money would be on less philosophers employed, more disease-control specialists, which would quickly introduce counter agents that could be consumed by the local flora/fauna.