Characterization of a Novel RNA Virus Discovered in the Autumnal Moth Epirrita autumnata in Sweden

de Miranda, Joachim R.; Hedman, Harald; Onorati, Piero; Stephan, Jörg; Karlberg, Olof; Bylund, Helena; Terenius, Olle

The virus has a rather low prevalence in E. autumnata, with 0/86 pupae, 1/60 larvae, and 4/77 adults registering positive for the virus by RT-qPCR, as well as 0/52 O. brumata pupae ( Table 1 ). The identity of the PCR fragments of the positive samples was confirmed by sequence analysis. The five positive samples were collected from three different sampling sites. The virus titers were about three orders of magnitude higher in the four virus-positive adult samples (2~25 × 10 9 copies/individual) than in the larval sample (5 × 10 6 copies/individual). These data, indicating host status for the adults but uncertainty for larvae or pupae, present an interesting conundrum concerning the origin and transmission of Abisko virus. Since the adult moths do not feed, are only alive for a few weeks in late autumn and the females are largely immobile [32] , they represent dead-end hosts for the virus. Either the virus has a more significant host elsewhere and the infection of E. autumnata adults is an accidental irrelevance, possibly involving acquisition during the larval phase and undetectable persistence through the pupal stage. Alternatively, E. autumnata is a primary host and transmission between individuals is through a mobile vector (parasitic wasps, for example).