Serological Investigation and Genetic Characteristics of Pseudorabies Virus in Hunan Province of China From 2016 to 2020

Abstract

Pseudorabies (PR), caused by variant pseudorabies virus (PRV), is an economically important viral disease in China. Recently, PRV infection in humans has also received attention worldwide. To investigate the PRV infection in Hunan province, China, we collected a total of 18,138 serum specimens from 808 PRV-vaccinated pig farms cross this region during 2016–2020, and we detected the presence of PRV glycoprotein B (gB) and gE-specific antibodies. The enzyme-linked immunosorbent assay (ELISA) results revealed that 80.47% (14,596/18,138, 95 CI 79.9–81.0) and 23.55% (4,271/18,138, 95 CI 22.9–24.2) of serum samples were positive for PRV gB and gE-specific antibodies, respectively. Further analysis indicated that the seroprevalence of wild PRV infection was associated with the season and breeding scale (p < 0.01). In addition, five PRV strains were isolated from PRV-positive samples in Vero cells and the virus titers varied from 106.5 to 107.51 TCID50/0.1 ml. The phylogenetic analysis revealed that one isolate was a classical strain of PRV genotype II, and four other isolates belonged to the variants of genotype II. Collectively, the data indicate that the prevalence of PRV remains high in pigs in Hunan province, and the variant PRV strains are the major genotypes affecting the development of the pig industry.

Epidemiological Investigation and Genetic Analysis of Pseudorabies Virus in Yunnan Province of China from 2017 to 2021

“…Pseudorabies (PR) is a devastating infectious disease that poses a huge threat to the development of the pig industry worldwide [ 1 ]. The causative agent of PR, pseudorabies virus (PRV) or Suid herpesvirus (SuHV-1), is an enveloped double-stranded DNA virus that belongs to the subfamily Alphaherpesvirinae of the family of Herpesviridae [ 2 ]. Pigs are known as the natural host and reservoir for PRV.…”

“…Pigs are known as the natural host and reservoir for PRV. The clinical symptoms of pigs infected with PRV vary depending on the growth stages: in newborn piglets, PRV infection causes severe diarrhea, vomiting, and neurological symptoms, resulting in high morbidity; in pregnant sows, PRV infection leads to reproductive failure [ 2 , 3 ]. Moreover, PRV has an intensive cross-species transmission capacity, which can infect a wide variety of animals, such as pigs, ruminants, carnivores, bears, etc.…”

“…Since the first detection of PRV in the United States, the disease caused by this pathogen has been observed in many countries, including Canada, China, and Hungary [ 6 ]. PR has been successfully controlled or eradicated in some countries or regions, such as Canada and Mexico, due to the application of multiple diagnosis approaches and glycoprotein E (gE)-deleted live or attenuated PRV vaccines [ 2 ]. However, this infectious disease remains widely prevalent in Chinese populations.…”

“…Currently, PRV strains are composed of two genotypes (genotype I and genotype II). PRV strains from Europe and USA belong to the genotype I, while most of genotype II PRV strains are isolated from Asian countries, mainly in China [ 2 ]. Moreover, the genotype II strains can be further divided into two sub-genotypes (classical PRV strains and variant PRV strains) [ 2 ].…”

A Triple Gene-Deleted Pseudorabies Virus-Vectored Subunit PCV2b and CSFV Vaccine Protects Pigs against PCV2b Challenge and Induces Serum Neutralizing Antibody Response against CSFV

“…Additionally, a highly neurovirulent PRV strain was recently isolated from pigs vaccinated with PRV Bartha K-61 [15,16]. Notably, the Bartha K-61 vaccine does not protect the vaccinated pigs clinically against the neurovirulent PRV strain [15][16][17][18]65,66].…”