Severe Acute Hepatitis Outbreaks Associated with a Novel Hepacivirus in Rhizomys pruinosus in Hainan, China

Molecular epizootiology of porcine reproductive and respiratory syndrome virus in the Xinjiang Uygur Autonomous Region of China

Rapid evolution of porcine reproductive and respiratory syndrome virus (PRRSV) is the bottleneck for effective prevention and control of PRRS. Thus, understanding the prevalence and genetic background of PRRSV strains in swine-producing regions is important for disease prevention and control. However, there is only limited information about the epizootiological situation of PRRS in the Xinjiang Uygur Autonomous Region, China. In this study, blood or lung tissue samples were collected from 1,411 PRRS-suspected weaned pigs from 9 pig farms in Changji, Shihezi, and Wujiaqu cities between 2020 and 2022. The samples were first tested by RT-quantitative PCR, yielding a PRRSV-2 positive rate of 53.6%. Subsequently, 36 PRRSV strains were isolated through initial adaptation in bone marrow-derived macrophages followed by propagation in grivet monkey Marc-145 cells. Furthermore, 28 PRRSV-positive samples and 20 cell-adapted viruses were selected for high-throughput sequencing (HTS) to obtain the entire PRRSV genome sequences. Phylogenetic analysis based on the nucleotide sequences of the ORF5 gene of the PRRSV strains identified in this study grouped into sub-lineages 1.8 and 8.7 the former being the dominant strain currently circulating in Xinjiang. However, the NSP2 proteins of the Xinjiang PRRSV strains shared the same deletion patterns as sub-lineage 1.8 prototype strain NADC30 with the exception of 4 strains carrying 2-3 additional amino acid deletions. Further analysis confirmed that recombination events had occurred in 27 of 37 PRRSVs obtained here with the parental strains belonging to sub-lineages 1.8 and 8.7, lineages 3 and 5, with the recombination events having occurred most frequently in the 5' and 3' termini of ORF1a and 5' terminus of ORF1b.

Outbreak of piglet diarrhea associated with a new reassortant porcine rotavirus B

Rotavirus B (RVB) is a causative agent leading to acute viral gastroenteritis diarrhea in both children and young animals, and has been commonly detected in piglets. In order to determine the causative agent of diarrheal outbreak occurring in December 2022 in piglets from a pig herd in Luoyang, Henan province of China, four common viral pathogens causing piglet diarrhea-three coronaviruses and rotavirus A (RVA) were first tested and found negative, therefore metagenomic sequencing was performed to explore other potential pathogens in the diarrheal samples. Unexpectedly, the most abundant viral reads mapped to RVB, and were de novo assembled to complete 11 viral gene segments. Sequence comparisons revealed that 5 gene segments encoding VP1, VP2, VP3, NSP3 and NSP4 of RVB strain designated as HNLY-2022 are most closely related to RVB strains derived from herbivores with low nucleotide similarities of 65.7-75.3%, and the remaining segments were relatively close to porcine RVB strains with the VP4 gene segment showing very low nucleotide identity (65.0%) with reference strains, indicating HNLY-2022 is a new reassortant RVB strain. Based on the previously proposed genotype classification criterion, the genotype constellation of RVB strain HNLY-2022 is G6-P[6]-I4-R6-C6-M6-A7-N5-T7-E5-H4 with more than half of the genotypes (P[6], R6, C6, M6, T7 and E5) newly reported. Therefore, the new reassortant RVB strain is the likely causative agent for the diarrheal outbreak of piglets occurred in China and more epidemiological studies should be conducted to monitor the spread of this newly identified porcine RVB strain.