First report of GI.1aP-GI.2 recombinants of rabbit hemorrhagic disease virus in domestic rabbits in China

Abstract

The rabbit hemorrhagic disease virus 2 (RHDV2 or GI.2) is a highly contagious agent leading to lethal disease in rabbits. It frequently recombines with other Lagovirus genus, generating epidemical variants with high pathogenicity. In this study, twenty-two liver samples tested positive for GI.2 VP60 gene, were collected in rabbit farms from several geographical regions in China. All GI.2 positive specimens were submitted for RT-PCR detection, nucleotide sequencing and phylogenetic analysis. In addition, suspected GI.2 recombinants were evaluated for virus virulence. The results showed that nine presumptive recombinants were identified by testing for RdRp-VP60 recombination. In these recombinants, four were selected to fully characterize the genome of novel GI.2 recombinant variants, which were described as GI.1aP-GI.2. The nucleotide sequence of these novel variants showed unique recombination pattern and phylogenetic features compared to currently prevalent GI.2 variants. Furthermore, this distinctive recombination of new variant SCNJ-2021 moderately enhanced the virulence of GI.2, even for rabbits vaccinated against parental GI.2. In conclusion, the novel GI.1aP-GI.2 recombinants were identified in rabbit industry in China for the first time, which expanded the knowledge on the phylodynamics and genomic diversity of GI.2 genotype. The rapid molecular evolution and varied pathogenicity of these virus recombinants highlight the urgent need for epidemiological surveillance and for future prevention of these neglected GI.2 variants.

Report on simultaneous infection of rabbit haemorrhagic disease virus type 1 and type 2 in kits in China

“…In addition, the outbreak of RHDV2 in Singapore in 2020 showed an Australian recombinant variant (Koh et al, 2023). First report of G .1aP-G .2 recombinants of RHDV in domestic rabbits in China (Li et al, 2023). However, for RNA viruses to recombine they need to be co-infected in the same host and replicate in the same cell at the same time, and the mutant strain must be able to successfully infect the new host (Worobey & Holmes, 1999).…”

Neglected Spleen Transcriptional Profile Reveals Inflammatory Disorder Conferred by Rabbit Hemorrhagic Disease Virus 2 Infection

“…The re-emerging rabbit hemorrhagic disease virus type 2 (RHDV2) caused an unexpected RHD outbreak in April 2020 in Sichuan Province, Southwest China [ 13 ]. Then, the outbreak rapidly spread among rabbit populations across broad geographic areas [ 14 ]. This outbreak was a suspected foreign invasion of RHDV2 due to its high nucleotide homology with Dutch isolates in 2016, which implicated its robust viral genetic fitness to damage the host immune defense in rabbit colonies [ 15 , 16 ].…”

Comment on Shah et al. Genetic Characteristics and Phylogeographic Dynamics of Lagoviruses, 1988–2021. Viruses 2023, 15, 815

“…Notably, recombination seems to have contributed to the emergence of GI.2 in 2010 by combining the non-structural proteins of a non-pathogenic GI.3 [ 2 ] with the structural proteins of a novel virus, GI.2 [ 14 ]. This novel virus was also shown to have recombined with pathogenic GI.1a and GI.1b, as well as non-pathogenic GI.4 [ 10 , 15 ], all contributing to the pool of circulating lagoviruses. Hares have also been a source of new viruses, with both pathogenic and non-pathogenic GII recombining with GI.2 [ 7 , 13 ].…”