Prevalence of Porcine Pseudorabies Virus and Its Coinfection Rate in Heilongjiang Province in China from 2013 to 2018

Abstract

Pseudorabies (PR) is a highly contagious disease affecting a wide range of animals, which annually causes great economic losses in China. In this study, a total number of 18,815 serum samples and 1,589 tissue samples were collected from 311 intensive pig farms (‡350 sows) located in eight cities in Heilongjiang province, and tested by ELISA and PCR. Overall, the serum positive rates of gE and gB protein were 16.3% and 84.5%, respectively. The PCR-positive rate of PR virus (PRV) in tissue samples was 17.8%. The coinfection rates of PRV with porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), and classical swine fever virus (CSFV) were also measured. The rate of PRV coinfected with PRRSV was 36.0% followed by 12.9% with PCV2 and 1.8% with CSFV, respectively. These results clearly demonstrate PRV prevalence and its coinfection rate in Heilongjiang province, indicating high PR endemic in pig farms in this region. This study provides data for further epidemiological investigations and a reference for developing PRV control strategies in this region and in China.

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

“…The variable temperature in autumn may partially state this result, and similar results were also reported in a previous study ( 17 ). Meanwhile, as reported in Zhou's study ( 21 ), the lowest PRV seroprevalence was also observed in fattening pigs, which might be associated with the limited breeding time.…”

“…PRV prevalence in pigs varied in different regions in China. In Henan province, 30.14% (1,419/4,708) of samples collected during 2018–2019 were gE-seropositive ( 17 ), while the serum gE-positive rate was 16.3% (3,067/18,815) in Heilongjiang province from 2013 to 2018 ( 21 ). All data indicate that seroprevalence of variant PRV is still high in China.…”

“…The present results showed that PRV classical strains were also prevalent in pig herds in Hunan province. Though Bartha-K61 vaccine can provide complete protection against the classical strain ( 10 , 19 ), some factors may contribute to vaccine failure, such as co-infection with PRRSV ( 21 ), indicating that the PR eradication or control cannot only rely on vaccination. Additionally, PRV recombinant isolates derived from genotype I and genotype II strains or classical and variant strains were often identified ( 26 , 27 ).…”

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].…”

“…Since PCV2, CSFV, and PRV are endemic, and co-infections are common in intensive pig farms in China [17], the severity and fatality of the disease and the emergence of a highly pathogenic PRV strain could have been the result of complex epidemiological interactions between the PRV and co-infecting virus(es) [18]. Both CSFV and PRV have been eradicated in the US and many European countries.…”