First report of Rabbit hemorrhagic disease virus 2(GI.2) in China

Rabbit haemorrhagic virus (RHDV) is a highly infectious and fatal pathogen to rabbits. Classic RHDV is mainly pathogenic to adult rabbits; however, it is not lethal to young rabbits. Since 2010, a RHDV variant has become prevalent in Europe and the Australian continent. This variant, which was named RHDV2 (GI.2/RHDVb), is highly infectious and fatal to both adult and young rabbits; moreover, its host range is broader than that of classic RHDV (GI.1/G1-6). In May 2020, the first RHDV2 case in China was reported. Here, we report and describe the first RHDV2 case in China. We amplified its complete genome sequence (named SC20-01 strain). The phylogenetic tree showed that the SC20-01 strain is mostly related to two strains isolated in Europe, which indicated that it might have spread from Europe to China. Moreover, Recombination Detection Program software showed that the SC20-01 strain is a G6/RHDV2 recombinant strain. Animal experiments showed that the SC20-01 strain is a highly fatal pathogen to specific-pathogen-free (SPF) rabbits and induces typical clinical symptoms of RHD. Our findings highlight RHDV2 emergence in China and its potential to spread widely. There is a need for more attention on the RHDV2 threat in China and the development of new diagnostic methods and vaccines for preventing the spread of RHDV2.