Hemoglobins C and S (HbC and HbS, respectively) are associated with an increase in malaria parasite ― transmission from the human host to the mosquito, according to a study published online this week in Nature Genetics. These results suggest that the host's genetic variations can affect transmission rates of malaria.
Malaria is a life-threatening disease caused by the Plasmodium parasites and transmitted to humans via infected mosquitoes. It is known that genetic variants in two types of hemoglobin, HbC and HbS, protect against malaria.
David Modiano and colleagues investigated whether HbC and HbS also affect the transmission of the malaria parasite from human to mosquito. The scientists conducted a large survey of close to 4000 individuals in rural West Africa and observed higher levels of infectious parasites in HbC genetic variant carriers. Next, the scientists performed transmission experiments involving over 6000 mosquitoes that received genotype-controlled blood meals. They observed that transmission of the malaria parasite from human blood to mosquito is enhanced when the blood meal came from individuals carrying HbC.