The Sinnis Laboratory is part of the Johns Hopkins Malaria Research Institute, committed to the pursuit of basic science research that translates into solutions targeting one of the most important infectious diseases in the world. Malaria, caused by protozoan parasites of the genus Plasmodium, is transmitted to humans by infected Anopheles mosquitoes. The evolution of drug resistance by the parasite, and insecticide resistance by the mosquito, have created an urgent need for new strategies to control and ultimately eradicate this scourge. Our research focuses on the infective stage of the malaria parasite, sporozoites, which are inoculated into the skin by infected mosquitoes. Sporozoites make an impressive journey from the midgut wall of the mosquito where they emerge from oocysts, to their final destination, the mammalian liver. Using biochemical, cell biological, and genetic approaches as well as intravital imaging and proteomics, we aim to understand the molecular interactions between sporozoites and their mosquito and mammalian hosts that enable the parasite to initiate infection. Recently we have started investigation the quantitative dynamics of transmission from mosquito to mammalian host, an understudied yet important area of inquiry if we are to improve our epidemiologic models and define the minimum efficacy required of transmission blocking interventions.