National Geographic : 2007 Jul
VACCINE STRATEGY Block develop ment of the parasite in the mosquito. NtoSQUITO STAGES Female f Fertilization MOVING TARGET SThe complex life cycle of the malaria parasite makes it difficult to fight with a vaccine. Male Research is targeting stages of the cycle in both human and mosquito hosts. S7 THE LIFE CYCLE 1 A mosquito injects sporozoites into the bloodstream. 2 They invade * Skin liver cells and transform into merozoites. 3 Each cell ruptures, Releasing tens of thousands of merozoites. Penetrating a red blood Scell, a merozoite multiplies. 4 Each red cell bursts and releases SFemale 6 more merozoites. 5 They infect more red blood cells and multiply S Male again. 6 Some merozoites develop into male and female forms o called gametocytes. 7 Feeding on a person with malaria, a mosquito ingests the gametocytes. 8 They reproduce 5 and develop into oocysts, which rupture and release sporozoites. 9 The sporozoites migrate from the I mosquito's gut to the salivary glands, ready to be 2 O Red blood injected into a human host. , cell Red blood cell S Fever and chills flare during the red-blood Scell cycle. A0 4,QC SOURCES:CENTERSFORDISEASECONTROLAND PREVENTION; MALARIARESEARCHPROGRAM,WALTERREEDARMYINSTITUTE OFRESEARCH;PATHMALARIAVACCINEINITIATIVE NGM ART;REPORTEDBY HUGHK. TRUSLOW 0 ;^s Salivary lands Skin / 0 N MALARIA 55 VACCINE STRATEGY Block parasites from entering liver cells or growing inside them.