Evolutionary relationship of the L- and M-class genome segments of bat-borne fusogenic orthoreoviruses in Malaysia and Australia.

We previously described three new Malaysian orthoreoviruses designated Pulau virus, Melaka virus and Kampar virus. Melaka and Kampar viruses were shown to cause respiratory disease in humans. These viruses, together with Nelson Bay virus, isolated from Australian bats, are tentatively classified as different strains within the species Pteropine orthoreovirus (PRV), formerly known as Nelson Bay orthoreovirus, based on the small (S) genome segments. Here we report the sequences of the large (L) and medium (M) segments, thus completing the whole-genome characterization of the four PRVs. All L and M segments were highly conserved in size and sequence. Conserved functional motifs previously identified in other orthoreovirus gene products were also found in the deduced proteins encoded by the cognate segments of these viruses. Detailed sequence analysis identified two genetic lineages divided into the Australian and Malaysian PRVs, and potential genetic reassortment among the M and S segments of the three Malaysian viruses.