Recombination between G2 and G6 strains of rabbit hemorrhagic disease virus (RHDV) in China.

Rabbit hemorrhagic disease (RHD) is an acute fatal disease caused by the lagovirus rabbit hemorrhagic disease virus (RHDV), which was first reported in 1984 in China. Genetic characterization of RHDV has demonstrated that two different genogroups (G2 and G6) are present in China. To gain a better understanding of the molecular evolution of RHDV, we searched for recombination events by analyzing all full-length RHDV capsid VP60 sequences of Chinese isolates belonging to the genogroups 2 and 6. Our results revealed a recombinant origin for the NanBu/China/2011 isolate. This recombination event occurred between G2 and G6 strains with two breakpoints located at nucleotide positions 393 and 1079 of the VP60 sequence. Phylogenetically, the NanBu/China/2011 strain clustered with genogroup G6 in the entire capsid gene sequence except in the fragment between nucleotides 394 and 1078, where it clustered with genogroup G2. As the consequences of the presence of a G2/G6 recombinant strain in China are unpredictable, the circulation of RHDV in the populations should be carefully monitored.