Dr. Edward Hoover's laboratory focused for 3 decades on the pathogenesis and intervention for retrovirus infections--in particular feline leukemia virus (FeLV), the feline and simian immunodeficiency viruses (FIV, SIV), and in the most recent decade on the prion disease chronic wasting disease (CWD) of deer and elk. These infections are important as diseases of animals and as models for cognate human diseases--i.e. leukemia, HIV infection/AIDS, bovine spongiform encephalopathy (mad cow disease, BSE), and Creutzfeld-Jakob, Alzheimer’s, and Parkinson’s diseases. Research in the Hoover laboratory led to development of the first successful and most widely used FeLV vaccine, now used to immunize cats worldwide against leukemia. Current work focuses on: (1) the mechanisms trans-mucosal prion infection and excretion; (2) detection of prions in body fluids of live animals; (3) the CWD species barrier in cervid and non-cervid species; and (4) experimental vaccines for prion and protein misfolding diseases.