Rabbit Hemorrhagic Disease Virus Isolated from Diseased Alpine Musk Deer (Moschussifanicus)
Shijun Bao1, Kai An1, Chunguo Liu2
1College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China.
Abstract:
Rabbit hemorrhagic disease virus (RHDV) is the causative agent of rabbit hemorrhagic disease (RHD), and its infection results in mortality of 70-90% in farmed and wild rabbits. RHDV is thought to replicate strictly in rabbits. However, there are also reports showing that gene segments from the RHDV genome or antibodies against RHDV have been detected in other animals. Here, we report the detection and isolation of a RHDV from diseased Alpine musk deer (Moschussifanicus). The clinical manifestations in those deer were sudden death without clinical signs and hemorrhage in the internal organs. To identify the potential causative agents of the disease, we used sequence independent single primer amplification (SISPA) to detect gene segments from viruses in the tissue samples collected from the dead deer. From the obtained sequences, we identified some gene fragments showing very high nucleotide sequence similarity with RHDV genome. Furthermore, we identified caliciviral particles using an electron microscope in the samples. The new virus was designated as RHDV GS/YZ. We then designed primers based on the genome sequence of an RHDV strain CD/China to amplify and sequence the whole genome of the virus. The genome of the virus was determined to be 7437 nucleotides in length, sharing the highest genome sequence identity of 98.7% with a Chinese rabbit strain HB. The virus was assigned to the G2 genotype of RHDVs according to the phylogenetic analyses based on both the full-length genome and VP60 gene sequences. Animal experiments showed that GS/YZ infection in rabbits resulted in the macroscopic and microscopic lesions similar to that caused by the other RHDVs. This is the first report of RHDV isolated from Alpine musk deer, and our findings extended the epidemiology and host range of RHDV.
Insights
Rabbit hemorrhagic disease virus (RHDV) was detected in Alpine musk deer, challenging the belief that it only infects rabbits. This discovery expands the known host range and epidemiology of RHDV.
Area of Science:
- Virology
- Ecology
- Veterinary Medicine
Background:
- Rabbit hemorrhagic disease virus (RHDV) causes high mortality in rabbits, with a known host range limited to rabbits.
- Previous findings suggested RHDV genetic material or antibodies in non-rabbit species, hinting at a broader epidemiological scope.
- The strict replication of RHDV solely within rabbits was a long-held assumption in the scientific community.
Purpose of the Study:
- To investigate the cause of sudden death and internal hemorrhages in Alpine musk deer.
- To identify and characterize the viral agent responsible for the disease in musk deer.
- To determine if RHDV can infect and replicate in species other than rabbits.
Main Methods:
- Sequence-independent single primer amplification (SISPA) was used to detect viral gene segments in deer tissues.
- Electron microscopy was employed to identify viral particles in collected samples.
- Whole-genome sequencing and phylogenetic analysis were performed on the isolated virus, designated RHDV GS/YZ.
Main Results:
- RHDV genetic fragments with high sequence similarity to known RHDV strains were identified in diseased musk deer.
- Caliciviral particles were observed in deer samples, confirming the presence of a viral infection.
- The isolated virus, RHDV GS/YZ, shared 98.7% genome sequence identity with a Chinese rabbit RHDV strain and belonged to the G2 genotype.
- Experimental infection of rabbits with RHDV GS/YZ caused lesions consistent with RHDV infection.
Conclusions:
- This study reports the first isolation of RHDV from Alpine musk deer, expanding the known host range of the virus.
- The findings demonstrate that RHDV can infect and cause disease in musk deer, challenging previous assumptions about its host specificity.
- The extended epidemiology and host range of RHDV have significant implications for wildlife health and disease management strategies.
