The outbreak of rabbit hemorrhagic virus type 2 in the interior of China may be related to imported semen

Abstract

1. •

   We identified one RHD case caused by a new RHDV variant (GI.2) in China through HA, TEM, and genome sequencing.

2. •

   This is the first study to demonstrate that GI.2 can replicate efficiently in the reproductive system.

3. •

   Our evidence suggests that GI.2 might be introduced into China by contaminated rabbit semen.

Fig. 1

EM images and phylogenetic analysis of the GI.2 SC20-01 strain. A EM images of viral particles extracted from the supernatants of the homogenized livers of infected rabbits. The supernatants of the homogenized livers were clarified with a 30% sucrose solution. Icosahedral symmetry viral particles were observed with diameters ranging from 30 to 40 nm, which was consistent with those of RHDV (red arrows). BVP60 gene sequences of RHDV were inferred through the maximum likelihood method with 1000 replicates using MEGA5.0 software. C Similarity plot and results of bootscanning analyses of RHDV SC20-01 (MT737965) based on the full-length genome. CBAnd1 (KP090976) and P19 (KY765610) were used as putative parental strains, and JX/CHA/97 (DQ205345) was used as the control strain. A sliding window of 200 nucleotides, moving in 20-nucleotide steps, was used in this analysis. The X-axis indicates the percentage of similarity or permuted trees, and the Y-axis indicates the position of the full-length genome of RHDV. The genome of SC20-01 was divided by single break point into two regions, and the recombinant site was labeled. Structural protein-coding region (nt 5305–7378) (D) and non-structural protein-coding region (nt 10–5304) (E) sequences of RHDV were inferred through the maximum likelihood method with 1000 replicates using MEGA5.0 software. Black triangles with yellow labels indicates the recombination parental strains. Black dot with green label indicate the isolation strain.