Heterozygote advantage in cystic fibrosis: mosquito tests

Tests to demonstrate a preference by mosquitoes for stinging controls as opposed to obligate heterozygotes for Cystic Fibrosis proved negative. If a heterozygote advantage caused a lower malarial incidence in carriers in South West Africa, it must have worked through the malarial parasite being adversely affected by a serum factor. This remains to be tested.