Each year thousands of newborn infants, children and adults develop deafness and vertigo that are due to viral infection. Unfortunately, little is understood about how a virus damages the inner ear particularly, because the labyrinth is encased in dense temporal bone, making clinical evaluation difficult. As a consequence, we have limited ability to prevent, diagnose or treat inner ear viral infections. The long-term goal of this application is to understand how viruses cause deafness and vertigo through study of animal models. Specific objectives are: 1) to understand the pathogenesis of experimental viral infections of the inner ear in young and adult animals; 2) to determine the long-term consequences of acute viral labyrinthitis; 3) to determine the role of the immune system in causing inner ear damage in viral labyrinthitis. Experiments in this proposal will study inner ear infections from mumps, measles, influenza A, para-influenza, and herpes simplex viruses in newborn and adult guinea pigs. The project will involve clinical evaluations of hearing, virus isolation attempts from inner ear and light microscopy and electron microscopy and immunohistochemistry studies. The MBRS student will be actively involved in this research project. Students, under supervision, will learn basic virologic techniques, animal virologic techniques, histologic techniques, and immunochemistry techniques. Students will learn proper care in handling of research animals. Students will be expected to actively participate in weekly research conferences. After learning basic laboratory skills, students will be expected to design, implement, analyze, and report to a national meeting their independent research projects.