Malaria is caused by an oranism that invades the red blood cells.
The parasites multiply and soon ruture the red blood cells. This cycle of destruction causes chills fever and chronic illness. Malaria can be fatal if not treated. Unfortunately, those homozygous for sickle-cell usually die young. Though 2 heterozygotes producing children is great and 2 out of 4 of those children will be heterozygotes, like their parents and will also be immune to malaria.