Tk-deleted Pseudorabies Virus Retains High Pathogenicity in Rats

Lirong Zhang; Keyue Ruan; Guoju Sang; Zhaoyang Xu; Wu Tong; Hai Yu; Tongling Shan; Fei Gao; Liwei Li; Ning Kong; Guangzhi Tong; Hao Zheng

doi:10.2478/jvetres-2021-0056

Tk-deleted Pseudorabies Virus Retains High Pathogenicity in Rats

J Vet Res. 2021 Oct 26;65(4):401-405. doi: 10.2478/jvetres-2021-0056. eCollection 2021 Dec.

Authors

Lirong Zhang¹, Keyue Ruan¹, Guoju Sang¹, Zhaoyang Xu¹, Wu Tong¹, Hai Yu¹, Tongling Shan¹, Fei Gao¹, Liwei Li¹, Ning Kong¹, Guangzhi Tong^{1

2}, Hao Zheng^{1

2}

Affiliations

¹ Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
² Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou 225009, China.

Abstract

Introduction: The pseudorabies virus (PRV) gene encoding thymidine kinase (tk) is an important virulence-associated factor. Attenuation of PRV in susceptible animals is a frequent result of tk deletion. The aim of the study was to assess the pathogenicity of tk-deleted PRV in rats.

Material and methods: Sprague Dawley rats were infected with the tk-deleted PRV strain SuHV-1 ΔTK:247via intranasal or intramuscular inoculation. PRV loads in ten tissues from dead and euthanised rats were determined using real-time PCR.

Results: Infection with SuHV-1 ΔTK:247 could cause death in rats. The 50% lethal dose (LD₅₀) of SuHV-1 ΔTK:247 via intranasal inoculation was 10^3.16 TCID₅₀ in rats. Intramuscular inoculation required a higher dose of SuHV-1 ΔTK:247 (10^5.0 TCID₅₀). A high SuHV-1 ΔTK:247 titre was observed in the trigeminal ganglia or spinal cord of dead rats.

Conclusion: The results of this study show that rats are highly susceptible to PRV infection, and tk deletion did not completely diminish the pathogenicity of PRV in rats.

Keywords: pseudorabies virus; rat; thymidine kinase.