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     

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%     

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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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     

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,     

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     

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     

Zika virus and Zika fever

An emerging mosquito-borne arbovirus named Zika virus (ZIKV), of the family Flaviviridae and genus Flavivirus, is becoming a global health threat. ZIKV infection was long neglected due to its sporadic nature and mild symptoms. However, recently, with its rapid spread from Asia to the Americas, affecting more than 30 countries, accumulating evidences have demonstrated a close association between infant microcephaly and Zika infection in pregnant women. Here, we reviewed the virological, epidemiological, and clinical essentials of ZIKV infection.

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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     

Isolation,characterization, and phylogenic analysis of three new severe fever with thrombocytopenia syndrome bunyavirus strains derived from Hubei Province,China

Hubei Province is a major epidemic area of severe fever with thrombocytopenia syndrome bunyavirus(SFTSV) in China. However, to date, a few SFTSV strains have been isolated from Hubei Province, preventing effective studies of epidemic outbreaks. Here, we report three confirmed patients(2015–2016) with typical symptoms of severe fever with thrombocytopenia syndrome disease(SFTS) who were farmers resident in different regions in Hubei Province. Three new SFTSV strains were isolated from the serum samples of each patient. Characterization of viral growth properties showed that there were no significant differences in virus production. All strains were completely sequenced, and phylogenetic analysis showed that unlike the other strains from Hubei province, which belonged to the SFTSV C3 genotype, one of the three strains belonged to the SFTSV C2 genotype. These results suggested that multiple SFTSV genotypes have been circulating in Hubei Province, providing insights into SFTSV evolution and improving our understanding of SFTSV prevalence in Hubei Province.     

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     

Progress towards understanding the pathogenesis of dengue hemorrhagic fever

Dengue virus (DENV) is a mosquito-borne virus belonging to the Flaviviridae family. There are 4 serotypes of DENV that cause human disease through transmission by mosquito vectors. DENV infection results in a broad spectrum of clinical symptoms, ranging from mild fever to dengue hemorrhagic fever (DHF), the latter of which can progress to dengue shock syndrome (DSS) and death. Researchers have made unremitting efforts over the last half-century to understand DHF pathogenesis. DHF is probably caused by multiple factors, such as virus-specific antibodies, viral antigens and host immune responses. This review summarizes the current progress of studies on DHF pathogenesis, which may provide important information for achieving effective control of dengue in the future.

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Recent advances in the identification of the host factors involved in dengue virus replication

Dengue virus (DENV) belongs to the genus Flavivirus of the family Flaviviridae and it is primarily transmitted via Aedes aegypti and Aedes albopictus mosquitoes. The life cycle of DENV includes attachment, endocytosis, protein translation, RNA synthesis, assembly, egress, and maturation. Recent researches have indicated that a variety of host factors, including cellular proteins and microRNAs, positively or negatively regulate the DENV replication process. This review summarizes the latest findings (from 2014 to 2016) in the identification of the host factors involved in the DENV life cycle and Dengue infection.

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Hantavirus infection: a global zoonotic challenge

Hantaviruses are comprised of tri-segmented negative sense single-stranded RNA, and are members of the Bunyaviridae family. Hantaviruses are distributed worldwide and are important zoonotic pathogens that can have severe adverse effects in humans. They are naturally maintained in specific reservoir hosts without inducing symptomatic infection. In humans, however, hantaviruses often cause two acute febrile diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). In this paper, we review the epidemiology and epizootiology of hantavirus infections worldwide.

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Avian influenza virus directly infects human natural killer cells and inhibits cell activity

Natural killer (NK) cell is a key component of innate immunity and plays an important role in host defense against virus infection by directly destroying infected cells. Influenza is a respiratory disease transmitted in the early phase of virus infection. Evasion of host innate immunity including NK cells is critical for the virus to expand and establish a successful acute infection. Previously, we showed that human influenza H1N1 virus infects NK cells and induces cell apoptosis, as well as inhibits NK cell activity. In this study, we further demonstrated that avian influenza virus also directly targeted NK cells as an immunoevasion strategy. The avian virus infected human NK cells and induced cell apoptosis. In addition, avian influenza virion and HA protein inhibited NK cell cytotoxicity. This novel strategy has obvious advantages for avian influenza virus, allowing the virus sufficient time to expand and subsequent spread before the onset of the specific immune response. Our findings provide an important clue for the immunopathogenesis of avian influenza, and also suggest that direct targeting NK cells may be a common strategy used by both human and avian influenza viruses to evade NK cell immunity.

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A new strain of Crimean-Congo hemorrhagic fever virus isolated from Xinjiang,China

Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic tick-borne virus with a fatality rate of up to 50% in humans. CCHFV is widely distributed in countries around the world. Outbreaks of CCHFV infection in humans have occurred in prior years in Xinjiang Province, China. Epidemiological surveys have detected CCHFV RNA in ticks and animals; however, few isolates were identified. In this study, we identified and isolated a new CCHFV strain from Hyalomma asiaticum asiaticum ticks collected from north of Tarim Basin in Xinjiang, China. A preliminary investigation of infection and antigens expression of CCHFV was performed in newborn mice. The target tissues for CCHFV replication in newborn mice were identified. The analysis of the phylogenetic relationships with other Chinese strains suggested that diverse genotypes of CCHFV have circulated in Xinjiang for years. These findings provide important insights into our understanding of CCHFV infection and evolution as well as disease prevention and control for local residents.

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Recent advances in synthetic carbohydrate-based human immunodeficiency virus vaccines

An effective vaccine for human immunodeficiency virus (HIV) is urgently needed to prevent HIV infection and progression to acquired immune deficiency syndrome (AIDS). As glycosylation of viral proteins becomes better understood, carbohydrate-based antiviral vaccines against special viruses have attracted much attention. Significant efforts in carbohydrate synthesis and immunogenicity research have resulted in the development of multiple carbohydrate-based HIV vaccines. This review summarizes recent advances in synthetic carbohydrate-based vaccines design strategies and the applications of these vaccines in the prevention of HIV.

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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     

Stability of HIV-1 subtype B and C Tat is associated with variation in the carboxyl-terminal region

The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.