From my understanding, the vivax variety can bury into the liver and come back out in the future, whereas the falciparum type, which seems to have faster and deadlier results if untreated, once it is treated, is no longer in the body.

Or at least I hope so. I lived in Tanzania for a few years and I got malaria (I think falciparum) a few times. The first time it was the worst headache I've ever experienced. By the third or fourth time, I barely noticed that I had it and yet it was at maybe 5x or more the concentration it was when I first contracted it.

I have had both falciparum and vivax (different years), confirmed by lab tests. The treatment was exactly the same in both cases. While one of them was quite debilitating, the other felt like an ordinary flu. I forgot which is which. In both cases, I was prescribed a month's worth of medication to get rid of the plasmodium from the liver.

I don't live in a malaria-prone locality anymore, but when I did, the people did not consider it a deadly disease. I think access to medical facilities and good nutrition are the key factors why some populations consider it a deadly disease, and other populations don't.

That's my experience as well - I had it 17 years ago, was very ill for weeks, but recovered and haven't had any problems since (but am no longer exposed to risk of new infections). However, it used to be that in the US you could donate blood if you had seen a doctor and been symptom-free for 3 years. It's now a lifetime ban. So perhaps there's new evidence it's not so simple?

Edit: Or there just aren't many donors who have had malaria, so they err on the side of safety.

That's my understanding as well; there are multiple malaria (plasmodium) species, and their effects vary. Some are a one-time infection, and some come back periodically.

I never got it, so I don't know.

The way it was explained to me, is that it's a parasitic disease, and the parasites would embed eggs in tissues, with the possibility of the eggs (or whatever they are -spores?) being re-released in the future.