In recent years, NADC34‐like PRRSV had a strong impact on the pig industry in the United States and Peru; it was also detected in northeastern China in 2017. In this study, we conducted a retrospective survey of NADC34‐like PRRSV in Southwest China from 2016 to 2020. Five NADC34‐like PRRSV strains were detected in samples and their whole genomes were sequenced, designated as CHSCMY‐22019, CHSCYB‐32020, CHSCMS‐42020 and CHSCLS‐22020. This is the first discovery and report of an NADC34‐like PRRSV strain in Southwest China. Phylogenetic tree analysis based on the whole genome showed that the five NADC34‐like PRRSV strains belonged to sub‐lineage 1.5 of PRRV‐2. They had 100 aa deletions in the Nsp2 hypervariable region of VR2332, located at 329–428 aa, similar to the US isolate IA/2014/NADC34. Recombination analysis showed that CHSCCD‐42020 strain was the recombinant strain of QYYZ strain and IA/2014/NADC34 strain in China. The emergence of NADC34‐like PRRSV strains in Southwest China indicates a potential threat to PRRS prevention and control in pigs. This study improves our understanding of the epidemic status and genetic variation of NADC34‐like PRRSV strains in China.

JEV is one of the zoonotic pathogens that cause serious diseases in humans. JEV infection can cause abortion, mummified foetus and stillbirth in sows, orchitis and semen quality decline in boars, causing huge economic losses to pig industry. In order to investigate the epidemiology of JEV in pigs in Sichuan province, a rapid and efficient fluorescent Reverse transcription recombinase-aided amplification (RT-RAA) detection method was established. Aborted fetuses and testicular swollen boar samples were detected by RT-RAA in pigs in the mountain areas around Sichuan Basin, and the detection rate of JEV was 6.49%. The positive samples were identified as JEV GI strain and GIIIstrain by sequencing analysis. We analyzed the whole gene sequence of a positive sample for the GI virus. The Envelope Protein (E protein) phylogenetic tree analysis was far related to the Chinese vaccine strain SA14-14-2, and was most closely related to the JEV GI strains SH17M-07 and SD0810 isolated from China. The results showed that we established an efficient, accurate and sensitive method for clinical detection of JEV, and JEV GI strains were prevalent in Sichuan area. It provides reference for the prevention and control of JEV in Sichuan.

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Macrophages are crucial components of the immune system and play a critical role in the initial defense against pathogens. They are highly heterogeneous and plastic and can be polarized into classically activated macrophages (M1) or selectively activated macrophages (M2) in response to local microenvironments. Macrophage polarization involves the regulation of multiple signaling pathways and transcription factors. Here, we focused on the origin of macrophages, the phenotype and polarization of macrophages, as well as the signaling pathways associated with macrophage polarization. We also highlighted the role of macrophage polarization in lung diseases. We intend to enhance the understanding of the functions and immunomodulatory features of macrophages. Based on our review, we believe that targeting macrophage phenotypes is a viable and promising strategy for treating lung diseases.

Background Hepatitis E virus (HEV) is an important zoonotic pathogen, Genotypes 3 and 4 are the main zoonotic genotype. Due to the lack of mature and effective culture cell lines, researches on genotype IV swine HEV (SHEV‐4) infection and pathogenic mechanism have been carried out in pigs, gerbils and non‐human primate models. Objectives The aim of this study was to establish a rat infection model by intra‐peritoneal infection with SHEV‐4, which provided a new research idea and scientific basis for further revealing the mechanism of HEV infection and preventing HEV infection. Methods SHEV‐4 virus was administered intra‐peritoneally to 6‐ to 8‐week‐old mice to observe the serological changes and virus release. Results According to the results of the rat serum HEV IgG, ALT and AST levels, swine HEV, minus‐strand HEV RNA can infect Sprague–Dawley rats across species, and there are no obvious clinical symptoms after infection. HEV RNA was detected in most tissues and organs after infection, but the viral load was low. The liver had pathological changes of chronic hepatitis. Conclusions We found that the rat model of porcine HEV infection is a small animal model suitable for the study of HEV infection.