Isolation and phylogenetic study of Rift Valley fever virus from the first imported case to China

<正>Dear Editor,Rift Valley fever(RVF)is an anthropozoonosis caused by Rift Valley fever virus(RVFV).RVFV belongs to the Phlebovirus genus in the family Bunyaviridae,which is circulating among ruminants.Human infection with RVFV is generally asymptomatic,however,minority of patients develop severe RVF diseases like encephalitis or     

Molecular typing of non-polio enteroviruses isolated from acute flaccid paralysis cases in Iran from 2010 to 2015

<正>Dear Editor,Acute flaccid paralysis(AFP)is a complex syndrome often caused by polioviruses.While most countries have eradicated wild polioviruses by vaccination,AFP still remains a health problem in these countries.Most studies have highlighted non-polio enteroviruses(NPEVs)as     

CD95-CD95L interaction mediates the growth control of MHV68 immortalized B cells by cytotoxic T cells

<正>Dear Editor,The main limitation of the viral pathogenesis study of human gammaherpesviruses Epstein-Barr virus(EBV)and Kaposi sarcoma-associated herpesvirus(KSHV)is the absence of animal model owing to the narrow host tropism of both EBV and KSHV.Murine gammaherpesvirus 68(MHV68)encodes several genes involved in     

Entry of severe fever with thrombocytopenia syndrome virus

Severe fever with thrombocytopenia syndrome virus(SFTSV) is a globe-shaped virus covered by a dense icosahedral array of glycoproteins Gn/Gc that mediate the attachment of the virus to host cells and the fusion of viral and cellular membranes. Several membrane factors are involved in virus entry, including C-type lectins and nonmuscle myosin heavy chain ⅡA. The post-fusion crystal structure of the Gc protein suggests that it is a class Ⅱ membrane fusion protein, similar to the E/E1 protein of flaviviruses and alphaviruses. The virus particles are internalized into host cell endosomes through the clathrin-dependent pathway, where the low pH activates the fusion of the virus with the cell membrane. With information from studies on other bunyaviruses, herein we will review our knowledge of the entry process of SFTSV.     

Interplay between hepatitis C virus and ARF4

<正>Dear Editor,Hepatitis C virus(HCV)is a major cause of chronic liver diseases and hepatocellular carcinoma(HCC)with about71 million people globally infected.HCV encodes only10 viral proteins and its replication relies on host proteins.Many host factors including ADP-ribosylation factors     

Construction of an infectious cDNA clone of Tembusu virus isolated from breeder Peking ducks

正Dear Editor,Since April 2010,an outbreak of a new disease has elicited symptoms of high fever,loss of appetite,and reduction in egg production in layer ducks in eastern China;this phenomenon has now spread throughout China(Cao et al.,2011;Su et al.,2011).The causative agent of the disease was identified as Tembusu virus(TMUV),which was classified into the genus Flavivirus,     

Recombinant canarypox virus expressing the VP2 protein of infectious bursal disease virus induces protection in vaccinated SPF chickens

正Dear Editor,Infectious bursal disease virus(IBDV)causes infectious bursal disease,a highly contagious immunosuppressive disease that affects young chickens and causes economic losses in the poultry industry worldwide.IBDV replicates mainly in actively dividing B lymphocytes within the bursa of Fabricius(BF),leading to immunosuppression in affected flocks(Mahgoub et al.,2012).Viral protein 2(VP2),the only structural component of the IBDV     

Antigenicity of severe fever with thrombocytopenia syndrome virus nucleocapsid protein and its potential application in the virus serodiagnosis

<正>Dear Editor,Severe fever with thrombocytopenia syndrome virus(SFTSV)is a newly identified viral pathogen of the genus Phlebovirus in the family Bunyaviridae(Sun et al.,2012).SFTSV was first identified from patient serum samples in China(Li et al.,2013;Ning et al.,2015).SFTSV can cause a severe hemorrhagic fever-like disease with a reported case fatality rate ranging from 2.5%     

Retromer localizes to autophagosomes during HCV replication

<正>Dear Editor,Hepatitis C virus(HCV)is a positive-strand RNA virus that belongs to the genus Hepacivirus within the Flaviviridae family.HCV causes chronic liver diseases,and185 million people are infected(Messina et al.,2015).Currently,there is no approved vaccine to prevent hepatitis C.HCV induces autophagy through elevating reactive oxygen species(ROS)levels via the unfolded     

Characterization of a recombinant Akabane mutant virus with knockout of a nonstructural protein NSs in a pregnant goat model

正Dear Editor,Akabane virus(AKAV),an orthobunyavirus,is transmitted primarily by biting midges and is widely distributed throughout the world except the Europe.AKAV was first isolated from mosquitoes in Japan(Oya et al.,1961).Although pregnant cows,ewes,and goats infected with AKAV exhibit no clinical signs of disease,in utero infections result in abortion,premature birth,stillbirth,and     

Lipids,lipid metabolism and Kaposi’s sarcoma-associated herpesvirus pathogenesis

Lipids are essential for mammalian cells to maintain many physiological functions. Emerging evidence has shown that cancer cells can develop specific alterations in lipid biosynthesis and metabolism to facilitate their survival and various malignant behaviors. To date, the precise role of cellular lipids and lipid metabolism in viral oncogenesis is still largely unclear with only a handful of literature covering this topic to implicate lipid metabolism in oncogenic virus associated pathogenesis. In this review, we focus on the role of lipid biosynthesis and metabolism in the pathogenesis of the Kaposi’s sarcoma-associated herpesvirus, a common causative factor for cancers arising in the immunocompromised settings.

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Herpesviruses: epidemiology,pathogenesis, and interventions

<正>This special issue of the journal is dedicated to the recent research progress on human herpesviruses(HHVs).Human herpesviruses are distributed worldwide,and more than 90%of adults are infected by one or multiple HHVs.The HHV family contains three sub-families:the alpha sub-family[herpes simplex virus 1(HSV-1),HSV-2,     

Current status of severe fever with thrombocytopenia syndrome in China

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by SFTS virus (SFTSV). SFTSV is associated with a high mortality rate and has been reported in China, South Korea and Japan. SFTSV undergoes rapid changes owing to evolution, gene mutations, and reassortment between different strains of SFTSV. In this review, we summarize the recent cases and general properties of SFTS, focusing on the epidemiology, genetic diversity, clinical features, and diagnostics of SFTSV in China. From 2010 to October 2016, SFTS cases were reported in 23 provinces of China, with increased numbers yearly. Infection and death cases are mainly found in central China, where the Haemaphysalis longicornis ticks are spread. The national average mortality rate of SFTS infection was 5.3%, with higher risk to elder people. The main epidemic period was from May to July, with a peak in May. Thus, SFTS reminds a significant public health problem, and development of prophylactic vaccines and effective antiviral drugs will be highly needed.

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Hepatitis C virus-induced prion protein expression facilitates hepatitis C virus replication

Hepatitis C virus (HCV) infects approximately 180 million people worldwide. Significant progress has been made since the establishment of in vitro HCV infection models in cells. However, the replication of HCV is complex and not completely understood. Here, we found that the expression of host prion protein (PrP) was induced in an HCV replication cell model. We then showed that increased PrP expression facilitated HCV genomic replication. Finally, we demonstrated that the KKRPK motif on the N-terminus of PrP bound nucleic acids and facilitated HCV genomic replication. Our results provided important insights into how viruses may harness cellular protein to achieve propagation.

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Recent advances in the study of hepatitis B virus covalently closed circular DNA

Chronic hepatitis B infection is caused by hepatitis B virus (HBV) and a total cure is yet to be achieved. The viral covalently closed circular DNA (cccDNA) is the key to establish a persistent infection within hepatocytes. Current antiviral strategies have no effect on the pre-existing cccDNA reservoir. Therefore, the study of the molecular mechanism of cccDNA formation is becoming a major focus of HBV research. This review summarizes the current advances in cccDNA molecular biology and the latest studies on the elimination or inactivation of cccDNA, including three major areas: (1) epigenetic regulation of cccDNA by HBV X protein, (2) immune-mediated degradation, and (3) genome-editing nucleases. All these aspects provide clues on how to finally attain a cure for chronic hepatitis B infection.

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Human cytomegalovirus infection dysregulates neural progenitor cell fate by disrupting Hes1 rhythm and down-regulating its expression

Human cytomegalovirus(HCMV) infection is a leading cause of birth defects, primarily affecting the central nervous system and causing its maldevelopment. As the essential downstream effector of Notch signaling pathway, Hes1, and its dynamic expression, plays an essential role on maintaining neural progenitor/stem cells(NPCs) cell fate and fetal brain development. In the present study, we reported the first observation of Hes1 oscillatory expression in human NPCs, with an approximately1.5 hour periodicity and a Hes1 protein half-life of about 17(17.6 ± 0.2) minutes. HCMV infection disrupts the Hes1 rhythm and down-regulates its expression. Furthermore, we discovered that depleting Hes1 protein disturbed NPCs cell fate by suppressing NPCs proliferation and neurosphere formation, and driving NPCs abnormal differentiation. These results suggested a novel mechanism linking disruption of Hes1 rhythm and down-regulation of Hes1 expression to neurodevelopmental disorders caused by congenital HCMV infection.     

Identification of a novel torque teno mini virus in cerebrospinal fluid from a child with encephalitis

<正>Dear Editor,Anelloviruses,which are all single-strand circular DNA viruses,have extremely heterogeneous genetic features.To date,the family Anelloviridae is divided into 11genus,and the most dominated species include torque teno virus(TTV),torque teno mini virus(TTMV)and     

Extracellular vesicles: novel vehicles in herpesvirus infection

Herpesviruses are remarkable pathogens that have evolved multiple mechanisms to evade host immunity, ensuring their proliferation and egress. Among these mechanisms, herpesviruses utilize elaborate extracellular vesicles, including exosomes, for the intricate interplay between infected host and recipient cells. Herpesviruses incorporate genome expression products and direct cellular products into exosomal cargoes. These components alter the content and function of exosomes released from donor cells, thus affecting the downstream signalings of recipient cells. In this way, herpesviruses hijack exosomal pathways to ensure their survival and persistence, and exosomes are emerging as critical mediators for virus infection-associated intercellular communication and microenvironment alteration. In this review, the function and effects of exosomes in herpesvirus infection will be discussed, so that we will have a better understanding about the pathogenesis of herpesviruses.

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