Current Status and Challenge of Pseudorabies Virus Infection in China

Abstract

Pseudorabies (PR), also called Aujeszky's disease, is a highly infectious disease caused by pseudorabies virus (PRV). Without specific host tropism, PRV can infect a wide variety of mammals, including pig, sheep, cattle, etc., thereby causing severe clinical symptoms and acute death. PRV was firstly reported in China in 1950s, while outbreaks of emerging PRV variants have been documented in partial regions since 2011, leading to significant economic losses in swine industry. Although scientists have been devoting to the design of diagnostic approaches and the development of vaccines during the past years, PR remains a vital infectious disease widely prevalent in Chinese pig industry. Especially, its potential threat to human health has also attracted the worldwide attention. In this review, we will provide a summary of current understanding of PRV in China, mainly focusing on PRV history, the existing diagnosis methods, PRV prevalence in pig population and other susceptible mammals, molecular characteristics, and the available vaccines against its infection. Additionally, promising agents including traditional Chinese herbal medicines and novel inhibitors that may be employed to treat this viral infection, are also discussed.

Keywords: Diagnosis methods; Multiple-species infection; Prevalence; Prevention and control measures; Pseudorabies virus (PRV).

Fig. 1

Current sero-prevalence of pseudorabies virus in pigs. Results of 108 representative studies investigating PRV sero-prevalence in pigs across distinct regions covering 29 provinces of China. These data collected from Chinese and English databases from 2011 to the present were analyzed. Data of the regions marked with white were not available.

Fig. 2

Phylogenetic trees based on the different gene sequences, showing the genetic relationships among PRV strains from different hosts/regions, were constructed by the neighbor-joining method with a bootstrap test of 1000 replicates using MEGA 7.0 software. The hosts, countries, years, and GenBank accession numbers of the reference strains employed in this phylogenetic tree are labeled, Black and red diamonds represent isolates from human and vaccines generated.

Fig. 3

Alignment of partial amino acid sequence of gB (A), gC (B), and gD (C) genes of representative PRV strains (genotype I strains (eg. Bartha and Becker), classical (eg. Fa and Ea) and variant strains (JS-2012, hSD-1/2019, and HeN1) in the genotype II). Unique aa deletions/insertions existed between different PRV strains are shown in the green box.