Is it true that a very low platelet count can be caused by (a) a viral infection and (b) a bacteria in the blood that falls short of sepsis?

A temporary reaction: Yes low platelets count may be due to several reasons: -Viral infections most often cause a temporary decrease in platelet count. -Bacterial infections can cause either a low or elevated platelet count.

Basically no: If your platelet count is low (under 90,000 or so calls for.a workup), the stupidest thing that anyone can possibly do is say "it's probably a virus" or blame a bacterium that isn't cultured and isn't making you sick otherwise. I hope I have not misunderstood. Low platelets is serious, very low levels are often catastrophic, and almost always there's a real illness to find and treat.