Ljungan virus a candidate virus in association with several human diseases found in bank voles and yellow-necked mice for the first time in northern Italy

The Ljungan (picorna) virus (LV) was first isolated in 1998 from Swedish bank voles (Myodes glareolus) after clinically recognizable type-1 diabetes-like symptoms were noted in this species in Denmark. LV has subsequently been shown to induce type-2-like diabetes, as well as uterine resorptions, malformations, and neonatal death in CD-1 laboratory house mice, and has been found in wild voles in the USA, as well as in lemmings and laboratory rats. Intriguingly, the incidence of type-1 diabetes, Guillain-Barré syndrome and myocarditis in the human population is correlated with rodent population cycles in Sweden. In addition, LV has been associated with intrauterine fetal death in Sweden, and a preliminary study showed that children newly diagnosed with type-1 diabetes have significantly increased levels of LV antibodies compared to controls. It has been hypothesized that the bank vole as well as other small rodents could act as reservoirs and/or vectors of LV that may be a zoonotic agent several human diseases or pathologies, including economically important type-1 diabetes. Consequently, knowledge of the distribution LV among wild and domestic mammal species is crucial to assess its potential importance as a human pathogen, identify possible zoonotic sources of the virus and lay groundwork for possible vaccine development. Here we provide a review of the current understanding of the ecopathology of LV and present the first results from southern Europe. Using Real Time RT PCR, LV was confirmed in 50% (10/20) of bank voles and in 10% (2/20) of yellow-necked mice (Apodemus flavicollis) collected from an alpine meadow in northern Italy during 2006. LV-positive animals included males and females, adults and subadults. This is the first time LV has been reported in Italy and in yellow-necked mice. These results significantly increase the geographical and species range of LV. We believe the global distribution of this picornavirus, and its role as a zoonotic agent, deserve further attention.