Molecular Detection and Characterization of Porcine Astrovirus on the basis of Partial ORF1b/ORF2 Region

The porcine astrovirus (PAstV) is distributed globally and exists as five distinct lineages (PAstV1-PAstV5). PAstV is considered one of the important pathogen associated with diarrhea among pigs. In the present study, the PAstV was detected in 13.4% (19/141) of fecal samples including 14.4% (16/111) diarrheic and 10% (3/30) non-diarrheic samples by RT-PCR based on partial ORF1b/ORF2 gene from Haryana, India. The results indicated that the weaning piglets were more susceptible to PAstV infection followed by suckling piglets. The phylogenetic analysis of the viral strains revealed the circulation ofPAstV4 (55.5%) and PAstV2 (44.4%) lineages with PAstV4 being the predominant lineage. To conclude, RT-PCR screening followed by sequencing of PAstV revealed high genetic diversity among the PAstV strains suggesting the wide range of heterogeneity and possible recombination events of viral strains in the state.

Next-Generation Sequencing Reveals Four Novel Viruses Associated with Calf Diarrhea

Calf diarrhea is one of the common diseases involved in the process of calf feeding. In this study, a sample of calf diarrhea that tested positive for bovine coronavirus and bovine astrovirus was subjected to high-throughput sequencing. The reassembly revealed the complete genomes of bovine norovirus, bovine astrovirus, bovine kobuvirus, and the S gene of bovine coronavirus. Phylogenetic analysis showed that the ORF2 region of bovine astrovirus had the lowest similarity with other strains and gathered in the Mamastrovirus unclassified genogroup, suggesting a new serotype/genotype could appear. Compared with the most closely related strain, there are six amino acid mutation sites in the S gene of bovine coronavirus, most of which are located in the S1 subunit region. The bovine norovirus identified in our study was BNoV-GIII 2, based on the VP1 sequences. The bovine kobuvirus is distributed in the Aichi virus B genus; the P1 gene shows as highly variable, while the 3D gene is highly conserved. These findings enriched our knowledge of the viruses in the role of calf diarrhea, and help to develop an effective strategy for disease prevention and control.

Quadruple Recombination Events Discovered in Hepatitis E Virus

Hepatitis E virus (HEV) can infect humans, pigs, and many other animals, but the recombination of HEV has rarely been reported. In the present study, phylogenetic and recombination analyses were performed on 557 complete HEV genomes in GenBank. A potentially significant quadruple recombination event was identified by recombination detection analysis. The recombinant progeny virus HEV_32_Manchester_301214 was produced by recombination between the major parent HEPAC-44 and the minor parent HE-JA15-1335, thereby reflecting inter-genotype recombination. HEV_32_Manchester_301214 and HEPAC-44 belong to genotype 3, while HE-JA15-1335 belongs to genotype 1, and these three strains have all been separated from humans. Three breakpoints of the four recombination events occurred in the ORF2 region, while another occurred in the ORF1 region. This quadruple recombination event was confirmed by phylogenetic analysis. The genotype, host and the recombination regions of the three strains were analyzed. These results of the analyses provide valuable suggestions for future research on HEV diversity.

Increasing Recombinant Strains Emerged in Norovirus Outbreaks in Jiangsu, China: 2015–2018

From January 2015 to December 2018, 213 norovirus outbreaks with 3,951 patients were reported in Jiangsu, China. Based on viral RdRp and VP1 genes, eight genotypes, GII.2[P16] (144, 67.6%), GII.3[P12] (21, 9.9%), GII.6[P7] (5, 2.3%), GII.14[P7] (4, 1.9%), GII.4 Sydney[P31] (3, 1.4%), GII.1[P33] (1, 0.5%), GII.2[P2] (3, 1.4%), and GII.17[P17] (16, 7.5%) were identified throughout the study period. These genotypes were further regrouped as GII.R (Recombinant) and GII.Non-R (Non-recombinant) strains. In this report we showed that GII.R strains were responsible for at least 178 (83.6%) of 213 norovirus-positive outbreaks with a peak in 2017 and 2018. Most norovirus outbreaks occurred in primary schools and 94 of 109 (86.2%) outbreaks in primary schools were caused by GII.R, while GII.Non-R and GII.NT (not typed) strains accounted for 6 (5.5%) and 9 (8.3%) norovirus outbreaks, respectively. The SimPlot analysis showed recombination breakpoints near the ORF1/2 junction for all six recombinant strains. The recombination breakpoints were detected at positions varying from nucleotides 5009 to 5111, localized in the ORF1 region for four strains (GII.2[P16], GII.3[P12], GII.6[P7], and GII.14[P7]) and in the ORF2 region for the other (GII.4 Sydney[P31] and GII.1[P33]). We identified four clusters, Cluster I through IV, in the GII.P7 RdRp gene by phylogenetic analysis and the GII.14[P7] variants reported here belonged to Cluster IV in the RdRp tree. The HBGA binding site of all known GII.14 strains remained conserved with several point mutations found in the predicted conformational epitopes. In conclusion, gastroenteritis outbreaks caused by noroviruses increased rapidly in the last years and these viruses were classified into eight genotypes. Emerging recombinant noroviral strains have become a major concern and challenge to public health.

L1 Retrotransposons Are Transcriptionally Active in Hippocampus of Rat Brain

LINE1 (L1) is an autonomous, non-LTR retrotransposon and the L1 family of retrotransposons constitute around 17%, 20% and 23% in the human, mouse and rat genomes respectively. Under normal physiological conditions, the retroelements remain by and large transcriptionally silent but are activated in response to biotic and abiotic stress conditions and during perturbation in cellular metabolism. They have also been shown to be transiently activated under certain developmental programs. Using RT-PCR, we show that the L1 elements are transcriptionally active in the hippocampus region of the brain of four-month-old rat under normal conditions without any apparent stress. Twenty non-redundant LINE1-specific reverse transcriptase (RTase) sequences form ORF2 region were isolated, cloned and sequenced. Full length L1 element sequences complementary to the isolated sequences were retrieved from the L1 database. In silico analysis was used to determine the presence of these retroelements proximal (up to 10 kb) to the genes transcriptionally active in the hippocampus. Many important genes were found to be in close proximity of the transcriptionally active L1 elements. Transcriptional activation of the elements possibly affects the expression of the neighbouring genes.

Genetic diversity of acute bee paralysis virus in Slovenian honeybee samples

The genetic diversity of acute bee paralysis virus (ABPV) in honeybees was studied in Slovenia. A total of 248 honeybee samples obtained from 134 different apiaries in Slovenia were tested for the presence of ABPV by RT-PCR. Specific 398-base pair (bp) products were generated with primers amplifying the ORF2 region and 452-base pair (bp) products with primers amplifying the ORF1 region of the viral genome. To characterise the overall nucleotide diversity among the ABPV sequences, phylogenetic trees with 54 and 29 samples were constructed from 357 nucleotides from ORF2 and 408 nucleotides from ORF1, respectively. The nucleotide comparison of Slovenian ABPV strains revealed two distinct clusters in ORF2 and ORF1, showing 91.2–92.5% and 96.7–97.2% nucleotide identity, respectively. Comparison of data regarding the geographical location of the ABPV-positive samples with the constructed phylogenetic trees revealed the random distribution of the two clusters throughout Slovenia.

Sequence analysis and comparison of avian hepatitis E viruses from Australia and Europe indicate the existence of different genotypes

Avian hepevirus infections were detected in chickens suffering from big liver and spleen disease or hepatitis–splenomegaly syndrome in Australia, the USA and Europe. Available data indicate their genetic relationship to mammalian hepatitis E virus (HEV). In the present study, the near-complete genomic sequences of an Australian and a European isolate of avian hepatitis E virus (avian HEV) are reported for the first time. Furthermore, the phylogenetic relationship to other avian HEVs is determined. Sequence analyses of these isolates identified major genetic differences among avian HEVs. Most of them are located within the open reading frame (ORF)1 region, although only a few lie within conserved motifs of predicted domains. Non-silent mutations in the ORF2 region suggest the presence of potentially different epitopes among avian HEV isolates. Finally, phylogenetic analysis confirmed the distant relationship to mammalian HEV and additionally suggested that the avian HEVs can be separated into three different genotypes: 1 (Australia), 2 (USA) and 3 (Europe), indicating a geographical distribution pattern.