Islet autoantibodies present in association with Ljungan virus infection in bank voles (Myodes glareolus) in northern Sweden.

Bank voles are known reservoirs for Puumala hantavirus and probably also for Ljungan virus (LV), a suggested candidate parechovirus in type 1 diabetes etiology and pathogenesis. The aim of this study was to determine whether wild bank voles had been exposed to LV and if exposure associated to autoantibodies against insulin (IAA), glutamic acid decarboxylase 65 (GADA), or islet autoantigen-2 (IA-2A). Serum samples from bank voles (Myodes glareolus) captured in early summer or early winter of 1997 and 1998, respectively, were analyzed in radio binding assays for antibodies against Ljungan virus (LVA) and Puumala virus (PUUVA) as well as for IAA, GADA, and IA-2A. LVA was found in 25% (189/752), IAA in 2.5% (18/723), GADA in 2.6% (15/615), and IA-2A in 2.5% (11/461) of available bank vole samples. LVA correlated with both IAA (P = 0.007) and GADA (P < 0.001), but not with IA-2A (P = 0.999). There were no correlations with PUUVA, detected in 17% of the bank voles. Compared to LVA negative bank voles, LVA positive animals had higher levels of both IAA (P = 0.002) and GADA (P < 0.001), but not of IA-2A (P = 0.205). Levels of LVA as well as IAA and GADA were higher in samples from bank voles captured in early summer. In conclusion, LVA was detected in bank voles and correlated with both IAA and GADA but not with IA-2A. These observations suggest that exposure to LV may be associated with islet autoimmunity. It remains to be determined if islet autoantibody positive bank voles may develop diabetes in the wild. J. Med. Virol. 89:24-31, 2017.