Molecular epidemiology and genetic characteristics of pseudorabies virus between 2021 and 2023 in Henan Province of China.

Abstract

Importance: Pseudorabies (PR) is a significant disease that adversely affects the healthy growth of the pig industry in China. However, data on molecular epidemiology and genetic characterization of PRV is sparse.

Objective: This study examined the epidemic trends and variation characteristics of the PR virus (PRV) in Henan Province of China.

Methods: Six hundred eighty-eight clinically infected pig tissue samples were collected from 18 cities in Henan Province from January 2021 to March 2023 and tested for the PRV. The PRV was isolated from positive samples and identified by a polymerase chain reaction and immunofluorescence assay. The gB, gC, gD, and gE genes of the isolates were then amplified and sequenced for phylogenetic analysis. The gC and gE gene sequences of the isolates in this study were deduced to the respective amino acids for sequence analysis. Selected isolates were evaluated for pathogenicity in KM mice.

Results: The positive rate of PRV nucleic acid was 7.99% (55/688) in Henan Province, China. This study isolated eight PRV strains, all of which were genotype II variants. Seven isolates displayed unique amino acid mutations in the gC or gE proteins. The isolates of G22, HN4, QX, and QX2 can cause acute neurological symptoms in KM mice, with 50% lethal dose values of 10^4.2, 10^4.5, 10^5.2, and 10^4.8 50% tissue culture infectious doses, respectively.

Conclusions and relevance: This study revealed a high prevalence of the PRV in Henan Province, with genotype II variants being the predominant strains. These findings provide essential data for the prevention and control of the PRV.