The arenaviruses and hantaviruses are rodent-borne pathogens that cause significant morbidity and mortality in humans. Arenaviruses cause illnesses ranging from aseptic meningitis following infection with lymphocytic choriomeningitis virus (LCMV) to hemorrhagic fever syndromes following infection with Lassa, Junin, Machupo, and Guanarito viruses, whereas hantaviruses cause hantavirus cardiopulmonary syndrome (HCPS), a disease that carries a 30 - 50% mortality rate in the Americas. Viruses in both genera have RNA genomes that encode four open reading frames in either negative sense (hantavirus) or ambisense (arenavirus) fashion. Currently there are no licensed vaccines available for the prevention of arenavirus or hantavirus disease. Dr. Botten's research interests pertaining to these viruses include understanding how the host immune response contributes to pathogenesis and/or protective immunity, identifying novel host-pathogen interactions, understanding how these viruses regulate their replicative activity to establish persistent infection in reservoir rodents, and developing novel therapeutic agents and vaccines.