Dr. Krogstad's current research is aimed at the molecular and genetic bases of resistance to chloroquine and quinine, structure-activity relationships among antimalarials, the development of a transfection system in Plasmodium falciparum and the use of plasmid constructs with a proline-rich amino acid linker to enhance the immunogenicity of cloned malaria parasite antigens. Field studies are centered in Mali and focus on three issues: optimal strategies for the use of chloroquine, techniques for the characterization of individual clones from polyclonal field isolates, and the development of methods to study pathogenicity and parasite virulence.