Ebola is more an argument for colonialism than against open borders but let's not be picky.
Ebola is an example of a locally-originated virulent existential threat open borders fail to contain, biological, social or otherwise. Controlled borders, despite all the issues, at least can act as an immune system of sorts.
As per a recent comment this thread is meant to voice contrarian opinions, that is anything this community tends not to agree with. Thus I ask you to post your contrarian views and upvote anything you do not agree with based on personal beliefs. Spam and trolling still needs to be downvoted.