TBD's in blood banks is potentially a big deal.
I'm not quite sure how diagnostics for Bartonella are perceived, however.
For instance, if you test positive for Bb antibodies it may or may not be significant, depending on whether you have received any sort of treatment anytime post diagnosis. So you may have a raging case of unresolved Lyme because you received inadequate treatment, but by virtue of that fact - that you received treatment - a clinician could declare you Lyme free. Even if you come up PCR positive - not an easy thing to do outside of acute cases - the findings can be dismissed as remnants.
Same for Babesia, except most don't receive treatment just on the strength of positive antibody tests. A lab also has to be able to isolate the little savages in a blood smear, and that can be devilishly difficult to do the farther out from an acute infection one gets. So, there is the potential for individuals to test positive for Babesia antibodies, and in fact have an active infection, yet never receive treatment.
So I'm not clear on how that works for Bartonella. Will these positive antibody findings and PCR findings equate to declarations that that blood supply is infected with Bartonella like this study would seem to be warning? Or will an ID person come along and say the findings are likely not as ominous since the metrics were only capturing debris from old resolved infections? The politics and publicity associated with policing the blood bank may ensure that proper concern and action results.
Either way, I suspect the risk to the blood band as an issue will garner more attention in some quarters than the corresponding risk to the general population contracting the disease through a natural vector like a tick.
Incidentally, I have tested positive for both Bartonella and Babesia antibodies and have never been given the green light to receive treatment.