The pathogenesis of type 1 diabetes mellitus (T1DM) involves genetic and environmental factors. However, the process is complex and poorly understood. Research from the past few years has indicated that viral infections, particularly infection with enteroviruses, are associated with the development of T1DM. In addition, Knut Dahl-Jørgensen’s research group had previously detected a low-grade infection with live enteroviruses in the insulin-producing areas of the pancreas at the onset of disease (see image). These findings raise the possibility that antivirals could be used in the treatment of new-onset T1DM; this approach has now been tested in a phase II study from Knut Dahl-Jørgensen and colleagues.