Porcine epidemic diarrhea virus (PEDV) is a porcine enteric coronavirus, which is one of the main causative agents of porcine epidemic diarrhea (PED), with 100% morbidity and 80–100% mortality in neonatal piglets. Since 2010, large-scale PED caused by highly pathogenic variants of PEDV has occurred successively in China and other countries in the world, posing a great threat to the global pig industry. It has been demonstrated in many investigations that the classic attenuated vaccine strain, PEDV CV777, is insufficient to fully protect against the PEDV variants. Moreover, the maternally derived antibodies elicited by inactivated vaccines also cannot completely protect piglets from infection. In addition, feedback feeding poses a risk of periodic PEDV recurrence in pig farms, making it challenging to successfully limit the spread of PEDV in China. This review focuses on the etiology, epidemiology, antigenicity, and control strategies of PEDV in China and provides information for the formulation of effective control measures.

Hu sheep, a locally bred species in China known for its high productivity, is currently suffering from pneumonia. Here, we combine high-throughput 16SrRNA gene sequencing and bacterial culturing to examine the bacterial community in pneumonic Hu Sheep lungs (p < 0.05). The results showed that the abundance and diversity of lung bacteria in healthy sheep were significantly higher than those in pneumonia sheep (p = 0.139), while there was no significant difference between moderate and severe pneumonia. Furthermore, the composition of the lung microbiota community underwent significant alterations between different levels of pneumonia severity. The application of LEfSe analysis revealed a notable enrichment of Mannheimiae within the lungs of sheep afflicted with moderate pneumonia (p < 0.01), surpassing the levels observed in their healthy counterparts. Additionally, Fusobacterium emerged as the prevailing bacterial group within the lungs of sheep suffering from severe pneumonia. Integrating the results of bacterial isolation and identification, we conclusively determined that Mannheimia haemolytica was the primary pathogenic bacterium within the lungs of sheep afflicted with moderate pneumonia. Furthermore, the exacerbation of pneumonia may be attributed to the synergistic interplay between Fusobacterium spp. and other bacterial species. Our results provide new insights for guiding preventive and therapeutic measures for pneumonia of different severities in sheep.

Porcine epidemic diarrhea virus (PEDV) is a porcine enteric coronavirus globally, causing serious economic losses to the global pig industry since 2010. Here, a PEDV CH/Yinchuan/2021 strain was isolated in a CV777-vaccinated sow farm which experienced a large-scale PEDV invasion in Yinchuan, China, in 2021. Our results demonstrated that the CH/Yinchuan/2021 isolate could efficiently propagate in Vero cells, and its proliferation ability was weaker than that of CV777 at 10 passages (P10). Phylogenetic analysis of the S gene revealed that CH/Yinchuan/2021 was clustered into subgroup GIIa, forming an independent branch with 2020-2021 isolates in China. Moreover, GII was obviously allocated into four clades, showing regional and temporal differences in PEDV global isolates. Notably, CH/Yinchuan/2021 was analyzed as a recombinant originated from an American isolate and a Chinese isolate, with a big recombinant region spanning ORF1a and S1. Importantly, we found that CH/Yinchuan/2021 harbored multiple mutations relative to CV777 in neutralizing epitopes (S1⁰, S1^A, COE, and SS6). Homology modelling showed that these amino acid differences in S protein occur on the surface of its structure, especially the insertion and deletion of multiple consecutive residues at the S1⁰ epitope. In addition, cross-neutralization analysis confirmed that the differences in the S protein of CH/Yinchuan/2021 changed its antigenicity compared with the CV777 strain, resulting in a different neutralization profile. Animal pathogenicity test showed that CH/Yinchuan/2021 caused PEDV-typified symptoms and 100 mortality in 3-day-old piglets. These data will provide valuable information to understand the epidemiology, molecular characteristics, evolution, and antigenicity of PEDV circulating in China.

Bovine parainfluenza virus type 3 (BPIV3) is a significant pathogen in cattle, causing a range of respiratory symptoms from mild to severe. In this study, we isolated a BPIV3 (BPIV3/SX/2021) strain using Madin-Darby bovine kidney cells from a lung tissue sample obtained in Shaanxi province. The full length of the BPIV3/SX/2021 strain is 15,474nt, encoding six structural and three accessory proteins. A phylogenetic analysis revealed that SX2021strain belongs to BPIV3 genotype C, and the isolate shares the highest sequence homology with the other genotype C strains isolated in China. A genetic comparison of the BPIV3c strain isolated in China showed that some amino acid residues have mutations in the F and HN genes that affect the protein structure. Animal challenge experiments showed that experimental infection of guinea pigs with the BPIV3c strain SX2021 displayed depression and dyspnea clinical signs. Histopathological analysis of the lung and trachea showed that morphological changes consisted of lesions of bronchial epithelial cell shedding, alveoli septa thickening, focal fiber hyperplasia, and macrophage infiltration. The virus load analysis indicated that the SX2021 strain displayed a higher replication level in the lungs and trachea. These results provide strong evidence that the evolution of BPIV3, and the isolated BPIV3 strain SX2021 provide useful data to determine the pathogenesis of the virus.

Carlavirus sigmasolani (Potato virus S, PVS) is a globally distributed plant virus infecting cultivated potato (Solanum tuberosum), causing yield losses and reduced tuber quality in the host crop, yet its evolutionary history, global dissemination and population genetic structure remain incompletely understood. In this study, we conducted comprehensive phylogenetic and Bayesian phylogeographic analyses of PVS using all available complete genome and coat protein (CP) gene sequences from 35 countries. Genome-based phylogenetic reconstruction identified four major phylogroups (I–IV), with Phylogroup I comprising only Colombian isolates and Phylogroup IV showing the broadest geographic distribution. In contrast, CP gene-based analyses revealed seven phylogroups (I–VII), including regionally restricted Phylogroups V (Colombia) and VI (Ecuador), and the globally dominant Phylogroup VII. A time-scaled Bayesian phylogenetic framework estimated a mean substitution rate of 3.11 × 10^-4 substitutions/site/year (95% HPD: 2.19 × 10^-4–4.07 × 10^-4), and dated the most recent common ancestor (tMRCA) of PVS to approximately 1296 (95% HPD: 964–1578). Phylogeographic analysis based on CP gene sequences suggests that Ecuador is a likely center of origin for PVS, with intercontinental dissemination beginning in the 16th century and markedly accelerating during the 19th and 20th centuries. Iran and China were identified as major secondary hubs during this period, while Europe and the United States also contributed to global dissemination as important intercontinental transmission centers during the 20th and 21st centuries. Population genetic analyses indicated that South America retains the highest diversity, reinforcing its status as the center of origin, while the markedly lower diversity in Africa and Oceania suggests more recent introductions coupled with restricted gene flow. These data improve our understanding of PVS evolution, spread and population structure, supporting the development of effective monitoring and control strategies.