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. Author manuscript; available in PMC: 2021 Aug 1.
Published in final edited form as: Trends Parasitol. 2020 Jul 1;36(8):705–716. doi: 10.1016/j.pt.2020.05.011

Figure 1: Transmission bottlenecks in the Plasmodium life cycle.

Figure 1:

(A) Estimated parasite numbers during the different life cycle stages reveals that transmission to and from the mosquito is associated with significant decreases in parasite numbers (meros, merozoites; spz, sporozoites; sg salivary gland; EEFs, exoerythrocytic forms). Adapted from Povelones et al [111]. (B) Specific bottlenecks faced by Plasmodium sporozoites: Cartoon of the sporozoites journey from mosquito to mammalian host, highlighting the following bottlenecks: #1 Estimates suggest ~20% of oocyst sporozoites reach the salivary glands; #2 Less than 1% of salivary gland sporozoites are expelled during probing; #3 ~20% of inoculated sporozoites enter the bloodstream; #4 represents several unmeasured bottlenecks, namely the efficiency with which sporozoite arrest in the liver, enter hepatocytes, and develop into liver stages. Artwork by Brandy Lee Bennett.