In contrast to TBFV and MBFV, the NKV and PABV groups are not arboviruses and their replication is limited to only one natural host, i.e. rodents/bats (NKV) or mosquitoes (PABV). The high nucleotide divergence (Supplementary Figure S1B and S1C) and limited number of complete published sequences for members of the NKV and PABV groups precluded the use of both phylogenetic and thermodynamic approaches to RNA structure prediction. When MFold analysis was performed with available sequences, no thermodynamically stable RNA structures were observed in the region corresponding to the TBFV SL6 region. However, an SL6-like structure, with a similar apical loop CCAA motif was observed in KRV (PABV), upstream of the analogous TBFV SL6.