Could you have malaria and NOT be aware of it your entire life?

I need this as soon as possible. It's for a genotype ignment. An african female mates with a white man who is obviously a heterozygote. One child dies of sickle-cell disease and the other of malaria. The one who dies from sickle-cell checks out, but I need to know if she's zygous dominant or heterozygous. Her other two children survive and want to reproduce.