Viral infection is suspected to be one of the causes of diabetes. The destructive mechanisms employed by different viruses can result in either direct destruction of islet cells with rapid insulin deficiency, or in a more gradual loss of islet cells with the onset of diabetes occurring many years later.
In individuals affected by congenital rubella, the virus appears to have caused an autoimmune reaction against the pancreatic beta cells. This phenomenon has also been observed in conjunction with other viruses, and is hypothesized to be a frequent occurrence. Several laboratories are in the process of identifying the specific genetic determinants of different viral strains to help specify the effects on the beta cells of the pancreas (Diabetologia, August, 1993).