Porcine reproductive and respiratory syndrome (PRRS) is an acute, febrile, and highly contagious disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV). Glycoprotein 5 (GP5) is a glycosylated envelope protein encoded by the PRRSV ORF5, which has good immunogenicity and can induce the body to produce neutralizing antibodies. Therefore, study of GP5 protein is of great significance in the diagnosis, prevention, and control of PRRSV and the development of new vaccines. We reviewed GP5 protein genetic variation, immune function, interaction with viral protein and host proteins, induction of cell apoptosis, and stimulation of neutralizing antibodies. GP5 protein’s influence on virus replication and virulence, as well as its use as a target for viral detection and immunization are reviewed.

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious disease in the pig industry, but its pathogenesis is not yet fully understood. The disease is caused by the PRRS virus (PRRSV), which primarily infects porcine alveolar macrophages and disrupts the immune system. Unfortunately, there is no specific drug to cure PRRS, so vaccination is crucial for controlling the disease. There are various types of single and combined vaccines available, including live, inactivated, subunit, DNA, and vector vaccines. Among them, live vaccines provide better protection, but cross-protection is weak. Inactivated vaccines are safe but have poor immune efficacy. Subunit vaccines can be used in the third trimester of pregnancy, and DNA vaccines can enhance the protective effect of live vaccines. However, vector vaccines only confer partial protection and have not been widely used in practice. A PRRS vaccine that meets new-generation international standards is still needed. This manuscript provides a comprehensive review of the advantages, disadvantages, and applicability of live-attenuated, inactivated, subunit, live vector, DNA, gene-deletion, synthetic peptide, virus-like particle, and other types of vaccines for the prevention and control of PRRS. The aim is to provide a theoretical basis for vaccine research and development.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most serious infectious diseases that detrimentally affects the pig industry worldwide. The disease, which is typically difficult to control, is an immunosuppressive disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV), the genome of which (notably the NSP2 gene) undergoes rapid mutation. In this study, we sought to determine the genetic variation in the PRRSV-2 NSP2 gene in China from 1996 to 2021. Strain information was obtained from the GenBank database and analyzed from a molecular epidemiological perspective. We compared the nucleotide and amino acid homologies of the NSP2 sequences of different PRRSV-2 lineages, and examined phylogenetic relationships based on an analysis of the NSP2 sequences of 122 strains. The results revealed that NADC-30-like strains, which are represented by lineage 1, and HP-PRRSV strains, which are represented by lineage 8, were the most prevalent in China from 1996 to 2021. Close similarities were detected in the genetic evolution of lineages 3, 5, and 8. For nucleotide and amino acid sequence comparisons, we selected representative strains from each lineage, and for the NSP2 among different PRRSV-2 strains, we accordingly detected homologies of 72.5–99.8% and 63.9–99.4% at the nucleotide and amino acid levels, respectively, thereby indicating certain differences in the degrees of NSP2 amino acid and nucleotide variation. Based on amino acid sequence comparisons, we identified deletions, insertions, and substitutions at multiple sites among the NSP2 sequences of PRRSV-2 strains. Recombination analysis revealed the occurrence of five recombinant events among the 135 selected PRRSV-2 strains, and that there is a high probability of recombination of lineage 1 strains. The findings of this study enabled us to gain an in-depth understanding of the prevalence of PRRSV in China over the past 25 years and will contribute to providing a theoretical basis for evolution and epidemiology of the spread of PRRSV.

Since its successful isolation in China in 1995, the porcine reproductive and respiratory syndrome virus (PRRSV) has been mutating into highly pathogenic strains by constantly changing pathogenicity and genetic makeup. In this study, we investigated the prevalence and genetic variation of nonstructural protein 1 (NSP1) in PRRSV-2, the main strain prevalent in China. After formulating hypotheses regarding the biology of the NSP1 protein, the nucleotide and amino acid similarity of NSP1 were analyzed and compared in 193 PRRSV-2 strains. The results showed that NSP1 has a stable hydrophobic protein with a molecular weight of 43,060.76 Da. Although NSP1 lacked signal peptides, it could regulate host cell signaling. Furthermore, NSP1 of different strains had high nucleotide (79.6–100%) and amino acid similarity (78.6–100%). In the amino acid sequence comparison of 15 representative strains of PRRSV-2, multiple amino acid substitution sites were found in NSP1. Phylogenetic tree analysis showed that lineages 1 and 8 had different evolutionary branches with long genetic distances. This study lays the foundation for an in-depth understanding of the nature and genetic variation of NSP1 and the development of a safe and effective vaccine in the future.

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious and severe infectious disease caused by the PRRS virus (PRRSV). PRRS is characterized by reproductive disorders in sows and respiratory dysfunction in pigs. Non-structural protein 7 (NSP7) is one of the most conserved functional proteins in PRRSV, and it plays an important role in viral replication and humoral immune responses in infected hosts. This review discusses the biological characteristics of NSP7 to provide theoretical support for its application in PRRS diagnosis, novel vaccine design, and therapeutic drug development.

The Hepatitis E virus (HEV) causes acute and chronic Hepatitis E and is a global public health concern. HEV genotypes 3 (HEV-3) and 4 (HEV-4) are common to humans and animals, and domestic pigs and wild boars have been identified as the main reservoirs. However, limited information is available on the status of HEV infection in pigs, particularly in the Guangdong Province, China. This study aimed to investigate the seroprevalence of HEV in pig farms within the Guangdong Province. A total of 1568 serum samples were collected from 25 farms and tested for anti-HEV IgG antibodies. Enzyme-linked immunosorbent assay (ELISA) results revealed that 57.53% (902/1568) of serum samples from 24 farms (24/25, 96%) were positive for anti-HEV IgG antibodies. Year, season, region, and age were all linked risk factors for HEV in Guangdong, with season and region showing more significant impacts. The results showing a high seroprevalence of HEV confirmed its circulation among domestic pigs in the Guangdong Province, China. The presence of this antibody indicates that HEV infection was or is present on farms, posing a risk of zoonotic transmission of HEV from pigs to exposed workers and from pork or organs to consumption.