Abstract
Multiple sclerosis (MS) is a chronic disease of the CNS that typically begins in late adolescence or early adulthood. It is highly variable in its expression and severity. The cause of MS is unknown, but both genetic and environmental factors have been implicated in its pathogenesis. It is known that viruses can induce chronic neurological disease, but the pathogenetic process in unclear. A viral cause for MS has been postulated, but to date no single virus has been confirmed to be associated with the disease. Although most viral candidates are no longer considered as possible aetiological agents in MS, a few are still being investigated.