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Human herpes simplex virus (HSV), a double-stranded DNA virus belonging to the Herpesviridae family and alpha herpesvirus subfamily, is one of the most epidemic pathogens in the population. Cell-to-cell spread is a special intercellular transmission mechanism of HSV that indicates the virulence of this virus. Through numerous studies on mutant HSV strains, many viral and host proteins involved in this process have been identified; however, the mechanisms remain poorly understood. Here, we evaluated the effect of the membrane protein genes US7 and UL56 on cell-to-cell spread in vitro between two HSV-1 (HB94 and HN19) strains using a plaque assay, syncytium formation assay, and the CRISPR/Cas9 technique. US7 knockout resulted in the inhibition of viral cell-to-cell spread; additionally, glycoprotein I (US7) of the HB94 strain was found to promote cell-to-cell spread compared to that of the HN19 strain. UL56 knockout did not affect plaque size and syncytium formation; however, the gene product of UL56 from the HN19 strain inhibited plaque formation and membrane infusion. This study presents preliminary evidence of the functions of US7 and UL56 in the cell-to-cell spread of HSV-1, which will provide important clues to reveal the mechanisms of cell-to-cell spread, and contributes to the clinical drugs development. [ABSTRACT FROM AUTHOR]

Besides mosquitoes, ticks are regarded as the primary source of vector-borne infectious diseases. Indeed, a wide variety of severe infectious human diseases, including those involving viruses, are transmitted by ticks in many parts of the world. To date, there are no published reports on the use of next-generation sequencing for studying viral diversity in ticks or discovering new viruses in these arthropods from China. Here, Ion-torrent sequencing was used to investigate the presence of viruses in three Rhipicephalus spp. tick pools (NY-11, NY-13, and MM-13) collected from the Menglian district of Yunnan, China. The sequencing run resulted in 3,641,088, 3,106,733, and 3,871,851 reads in each tick pool after trimming. Reads and assembled contiguous sequences (contigs) were subject to basic local alignment search tool analysis against the GenBank database. Large numbers of reads and contigs related to known viral sequences corresponding to a broad range of viral families were identified. Some of the sequences originated from viruses that have not been described previously in ticks. Our findings will facilitate better understanding of the tick virome, and add to our current knowledge of disease-causing viruses in ticks living under natural conditions. [ABSTRACT FROM AUTHOR]

Highlights: [•] A mini-genome rescue system for the CCHFV Chinese YL04057 strain was developed. [•] Gradual reduced levels of activity with CCHFV L, M, and S UTRs were observed. [•] UTRs at both ends were indispensable for mini-genome background expression. [•] Compatibilities of YL04057-support plasmids and IbAr10200-mini-genomes were tested. [•] The CCHFV L-UTRs could tolerate site specific mutations. [ABSTRACT FROM AUTHOR]

Abstract: Infection with herpes simplex virus type 2 (HSV-2) can result in lesions in reproductive organs, along with long-term latency. In this work, a non-lethal strain of HSV-2 which was isolated clinically was used to infect female mice intravaginally. Body weight, vulval lesions, histological examination of vaginal tissue, and viral load were monitored and used as indices for evaluating antiviral drugs against HSV-2 infection. The results indicated that mice infected with HSV-2 exhibited significant reduction in body weight, serious vulval lesions, massive lymphocyte invasion of vaginal tissue, and approximately 104 copies/μl of HSV-2 were found in vaginal and uterine tissues. Aciclovir (ACV) treatment inhibited loss in body weight, genital pathology and virus replication (reduced to 100.3 copies/μl) effectively. The study provides a simple, reproducible and feasible animal model for anti-HSV-2 drugs evaluation and HSV-2 vaccine research. [Copyright &y& Elsevier]

Abstract: The embryonated chicken egg (ECE) provides a convenient, space-saving incubator for the cultivation of many kinds of animal viruses where the egg can be easily observed for viral replication throughout the development of the chicken embryo. Within the family Bunyaviridae, the embryonated egg has been used as a host system for many viruses such as Rift Valley fever virus and Akabane virus. The current study was conducted to determine the cultivation of Crimean-Congo hemorrhagic fever virus (CCHFV) in ECE. Four-day-old eggs were infected with CCHFV via the yolk sac route and harvested embryonic tissues and amino-allantoic fluid (AAF) that were used for virus passage and viral RNA (vRNA) detection. Quantification of vRNA copies was performed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Our study indicated that CCHFV caused the death of the embryonated egg in a dose-dependent manner and the 50% egg infectious dose (EID50) was determined to be 6.47×105 copies/egg. CCHFV replicated and passaged well in the egg and high viral loads were detected both in embryonic tissue (109–10 copies/g) and AAF (107–9 copies/ml) of the embryonated egg. Thus, ECE could be used for viral cultivation and preservation, and as a potential host infection model for the study of the pathogenesis of CCHFV. [Copyright &y& Elsevier]

Poyang Lake is the largest inland freshwater lake in China and contains many species of wild birds and waterfowls. We conducted a survey of avian influenza viruses in nine semi-artificial waterfowl farms in Poyang Lake during January to March of 2010. Out of 1036 cloacal swabs collected, three H3N2 and one H4N6 influenza viruses were isolated from healthy mallards. All the isolates were genetically and phylogenetically characterized. The analysis of putative HA cleavage sites showed that all the four isolates possessed the molecular characteristics (QTRGL for H3N2 viruses, PEKASR for H4N6 virus) of lowly pathogenic avian influenza (LPAI) virus. The phylogenetic analysis of the viral genomes showed that all four virus isolates clustered in the Eurasian clade of influenza viruses. The M gene of the viruses possessed the highest homology with highly pathogenic H5N1 influenza viruses. In addition, co-infection of H3N2 and H4N6 in the same farm was observed. And interestingly, we isolated two subtypes viruses (H3N2 and H4N6) and their progeny virus (H3N2) with evidence of genome reassortment from the same farm, in which the PB1 and PB2 gene segments of H4N6 replaced those of the H3N2 strain. The results of animal infection experiments showed that all the four isolated viruses were lowly pathogenic to chickens and not pathogenic to mice, which was consistent with the results of genetic analysis. [ABSTRACT FROM AUTHOR]

Summary: Objectives: We aimed to determine the seroprevalence of Crimean-Congo hemorrhagic fever virus (CCHFV) infection in Yunnan Province, China. Materials and methods: One thousand six hundred and fifty-seven human serum samples and 1280 ticks (Hyalomma asiaticum) were collected from five counties (Menglian, Menghai, Lancang, Mengla, and Ximeng). Serum samples were analyzed independently by indirect immunofluorescence assay and Western blotting to detected CCHFV antibody. The ticks were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) to detect virus RNA. Results: The CCHFV IgG positivity was 3.4% (57/1657). A multivariate analysis was performed, and variables that increased the chance of infection were found to include history of tick bite or contact (odds ratio (OR) 16.6, 95% confidence interval (CI) 7.5–37.0) and age>30 years (OR 6.8, 95% CI 1.6–28.2). The RT-PCR positive rate for ticks was 14.3% (6/42). Conclusions: The five counties (Menglian, Menghai, Lancang, Mengla, and Ximeng) in Yunnan are areas with the potential for CCHF outbreaks. Residents should protect themselves against tick bites and the surveillance of CCHFV in this region should be improved. [ABSTRACT FROM AUTHOR]