Viruses may be etiologic agents for non-insulin-dependent (type II) diabetes.

Although diabetes mellitus is generally subclassified into either of two categories, insulin-dependent (type I) and non-insulin-dependent (type II), the heterogeneity of its clinical expressions, genetics, and etiologies may make a clear distinction in classification difficult. Evidence to date for the involvement of viruses in the etiology of the disease has involved only type I diabetes. However, clinical data derived from the subtle chronicity of type II diabetes, the lack of pathological alterations in the pancreas in some patients with type II diabetes, and animal and human studies with Venezuelan encephalitis virus and rubella virus suggest a possible role for viruses in the pathogenesis of non-insulin-dependent diabetes.