Malaria caused half a billion clinical illnesses and a million or more deaths in 2007. Measuring the burden of malaria is difficult because clinical features overlap with other diseases, diagnosis is imperfect, and many of its sequelae are masked by the complex relationship of parasite to host to disease. The remarkable life cycle of the parasite offers many targets for intervention, and vaccines being developed against different stages of the life cycle have different objectives. Learn more about malaria from Patrick Duffy, professor, University of Washington department of Global Health, and director of the Malaria Program at the Seattle Biomedical Research Institute. From the Series:Laboratory Medicine Grand Rounds