Roos’ work seeks to integrate diverse disciplines, from molecular cell biology and pharmacology to computer science and international public health. Current interests focus on protozoan parasites, including Toxoplasma (a prominent congenital pathogen and opportunistic infection associated with AIDS) and Plasmodium (which causes malaria). Research in the Roos laboratory has yielded genetic tools for the dissection of parasite pathogenesis and drug resistance mechanisms, new insights into the evolution and function of subcellular organelles, and computational tools including databases making genomic-scale datasets accessible to scientists worldwide.

Roos has published numerous research reports in leading scientific journals, and received honors including the Presidential Young Investigator Award from the National Science Foundation, the Burroughs Wellcome Scholar Award, and the Ellison Medical Foundation Senior Scholar Award in Global Infectious Diseases. Deeply committed to education, Roos has taught courses for both general and specialized audiences, at Penn and elsewhere, and travels widely as a lecturer and consultant for the WHO and other organizations.