I once talked a teacher of mine into not omitting virology if I gave a talk about viruses. Now imagine if I would've had cuddly flu with me then to swing opinion for this topic
You could as well go for sickle cell anemia
's prevalence in tropical countries. Since it deforms red blood cells (in which plasmodiae live, in turn) it helps in a way to fend off the disease. In northern hemispheres, however, the variation is not as prevalent as it shows only mild downsides there (no malaria, but still you can't breathe as well).
Funny point: While the cells deform, crystallizing proteins build up needles that actually "pin up" the plasmodium
Mean, isn't it?