Clinical neuroscience, virology, immunology, and molecular biology come together in the study of neurovirology, which is an interdisciplinary field. The study of viruses that can infect the neurological system is the field's main focus. Viruses are also used to map neuroanatomical circuits, for gene therapy, and to eradicate harmful populations of brain cells, according to the field. The field of neurovirology has only been around for 30 years. It was founded on the observation that a wide range of viruses are capable of entering nerve tissue and developing latent infections. Slow, persistent, or progressive nervous system illnesses have been linked to such viruses.