The Asian Lineage of Zika Virus: Transmission and Evolution in Asia and the Americas

Since first isolation in 1947 from the Zika forest in Uganda, Zika virus(ZIKV) has been principally known as a benign agent associated with sporadic human infections in a restricted number of African countries. However, during 2015–2016,an Asian lineage of ZIKV caused an unprecedentedly large outbreak in the Americas and sizeable numbers of exported cases across the globe. In this review, we critically appraise the recent advances in molecular epidemiological studies of ZIKV performed to date, and we highlight the pivotal role played by genomic surveillance in elucidating the origins,dissemination and evolution of the Asian lineage of ZIKV in Asia and in the Americas.     

Recent Advances in Animal Models of Zika Virus Infection

An infection by Zika virus(ZIKV), a mosquito-borne flavivirus, broke out in South American regions in 2015, and recently showed a tendency of spreading to North America and even worldwide. ZIKV was first detected in 1947 and only 14 human infection cases were reported until 2007. This virus was previously observed to cause only mild flu-like symptoms.However, recent ZIKV infections might be responsible for the increasing cases of neurological disorders such as GuillainBarre′ syndrome and congenital defects, including newborn microcephaly. Therefore, researchers have established several animal models to study ZIKV transmission and pathogenesis, and test therapeutic candidates. This review mainly summarizes the reported animal models of ZIKV infection, including mice and non-human primates.     

Micro-droplet Digital Polymerase Chain Reaction and Real-Time Quantitative Polymerase Chain Reaction Technologies Provide Highly Sensitive and Accurate Detection of Zika Virus

The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we established micro-droplet digital polymerase chain reaction(ddPCR) and real-time quantitative PCR(RT-qPCR) protocols for the detection of ZIKV based on the amplification of the NS5 gene. For the ZIKV standard plasmid, the RT-qPCR results showed that the cycle threshold(Ct) value was linear from 10~1 to 10~8 copy/l L, with a standard curve R~2 of 0.999 and amplification efficiency of 92.203%;however, a concentration as low as 1 copy/l L could not be detected. In comparison with RT-qPCR, the dd PCR method resulted in a linear range of 10~1–10~4 copy/l L and was able to detect concentrations as low as 1 copy/l L. Thus, for detecting ZIKV from clinical samples, RT-qPCR is a better choice for high-concentration samples(above 10~1 copy/l L),while ddPCR has excellent accuracy and sensitivity for low-concentration samples. These results indicate that the ddPCR method should be of considerable use in the early diagnosis, laboratory study, and monitoring of ZIKV.     

Isolation and characterization of Zika virus imported to China using C6/36 mosquito cells

正Dear Editor,Zika virus(ZIKV)is a mosquito-borne flavivirus that usually causes asymptomatic infections or mild illness in humans.However,the unprecedented epidemics of ZIKV in Latin America since early 2015 have made this flavivirus an international health risk(Liu and Zhang,2016).In particular,the potential association of ZIKV infection with the remarkable increase in the number of     

Zika virus: a flavivirus caused pandemics in Latin America

正Since early 2015,an unprecedented outbreak of Zika virus(ZIKV)infection that recognized in northeast Brazil has spread to Latin America(Schuler-Faccini,2016).As of January 2016,there has been confirmed autochthonous transmission of ZIKV in 19 countries in the Americas outside Brazil(Hennessey,2016).In     

Generation of A Stable GFP-reporter Zika Virus System for High-throughput Screening of Zika Virus Inhibitors

Zika virus(ZIKV) is associated with severe birth defects and Guillain-Barre′ syndrome and no approved vaccines or specific therapies to combat ZIKV infection are currently available. To accelerate anti-ZIKV therapeutics research, we developed a stable ZIKV GFP-reporter virus system with considerably improved GFP visibility and stability. In this system a BHK-21 cell line expressing DC-SIGNR was established to facilitate the proliferation of GFP-reporter ZIKV. Using this reporter virus system, we established a high-throughput screening assay and screened a selected plant-sourced compounds library for their ability to block ZIKV infection. More than 31 out of 974 tested compounds effectively decreased ZIKV reporter infection. Four selected compounds, homoharringtonine(HHT), bruceine D(BD), dihydroartemisinin(DHA) and digitonin(DGT), were further validated to inhibit wild-type ZIKV infection in cells of BHK-21 and human cell line A549.The FDA-approved chronic myeloid leukemia treatment drug HHT and BD were identified as broad-spectrum flavivirus inhibitors. DHA, another FDA-approved antimalarial drug effectively inhibited ZIKV infection in BHK-21 cells. HHT, BD and DHA inhibited ZIKV infection at a post-entry stage. Digitonin was found to have inhibitory activity in the early stage of viral infection. Our research provides an efficient high-throughput screening assay for ZIKV inhibitors. The active compounds identified in this study represent potential therapies for the treatment of ZIKV infection.     

An Integrated Systems Biology Approach Identifies ZIKV and DENV Replication

The Zika virus(ZIKV) and dengue virus(DENV) flaviviruses exhibit similar replicative processes but have distinct clinical outcomes. A systematic understanding of virus–host protein–protein interaction networks can reveal cellular pathways critical to viral replication and disease pathogenesis. Here we employed three independent systems biology approaches toward this goal. First,protein array analysis of direct interactions between individual ZIKV/DENV viral proteins and20,240 human proteins revealed multiple conserved cellular pathways and protein complexes,including proteasome complexes. Second, an RNAi screen of 10,415 druggable genes identified the host proteins required for ZIKV infection and uncovered that proteasome proteins were crucial in this process. Third, high-throughput screening of 6016 bioactive compounds for ZIKV inhibition yielded 134 effective compounds, including six proteasome inhibitors that suppress both ZIKV and DENV replication. Integrative analyses of these orthogonal datasets pinpoint proteasomes as critical host machinery for ZIKV/DENV replication. Our study provides multi-omics datasets for further studies of flavivirus–host interactions, disease pathogenesis, and new drug targets.     

Rearrangement of Actin Cytoskeleton by Zika Virus Infection Facilitates Blood–Testis Barrier Hyperpermeability

In recent years,various serious diseases caused by Zika virus (ZIKV) have made it impossible to be ignored.Confirmed existence of ZIKV in semen and sexually transmission of ZIKV suggested that it can break the blood–testis barrier (BTB),or Sertoli cell barrier (SCB).However,little is known about the underlying mechanism.In this study,interaction between actin,an important component of the SCB,and ZIKV envelope (E) protein domain Ⅲ (EDⅢ) was inferred from coimmunoprecipitation (Co-IP) liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis.Confocal microscopy confirmed the role of actin filaments (F-actin) in ZIKV infection,during which part of the stress fibers,the bundles that constituted by paralleled actin filaments,were disrupted and presented in the cell periphery.Colocalization of E and reorganized actin filaments in the cell periphery of transfected Sertoli cells suggests a participation of ZIKV E protein in ZIKV-induced F-actin rearrangement.Perturbation of F-actin by cytochalasin D (CytoD) or Jasplakinolide (Jas)enhanced the infection of ZIKV.More importantly,the transepithelial electrical resistance (TEER) of an in vitro mouse SCB (mSCB) model declined with the progression of ZIKV infection or overexpression of E protein.Co-IP and confocal microscopy analyses revealed that the interaction between F-actin and tight junction protein ZO-1 was reduced after ZIKV infection or E protein overexpression,highlighting the role of E protein in ZIKV-induced disruption of the BTB.We conclude that the interaction between ZIKV E and F-actin leads to the reorganization of F-actin network,thereby compromising BTB integrity.     

COVER

正Recent large outbreaks of Zika vrius (ZIKV)in Oceania's islands and the Americas have linked the ZIKV infection with occurrence of microcephaly in newborns.The virus can be passed from a pregnant woman to her fetus.Even worse,ZIKV has now spread to nearly 30 areas worldwide and become     

Understanding the pathogenic evolution of Zika virus

正Unlike the previous circulating strains that were not associated with significant human pathology,recent circulating Zika virus(ZIKV)strains isolated during the 2015–2016Brazilian Outbreak are highly suspected to cause neuropathology,including disorders of fetal brain development and Guillain-Barrésyndrome(Broutet et al.,2016).Studies have revealed that recent ZIKV strains can be spread through maternal-fetal(Calvet et al.,2016)and sexual(Hills et al.,2016)transmission,in addition to the traditional route     

ZIKV viral proteins and their roles in virus-host interactions

The re-emergence of Zika virus(ZIKV) and its associated neonatal microcephaly and Guillain-Barré syndrome have led the World Health Organization to declare a global health emergency. Until today, many related studies have successively reported the role of various viral proteins of ZIKVin the process of ZIKVinfection and pathogenicity. These studies have provided significant insights for the treatment and prevention of ZIKV infection. Here we review the current research advances in the functional characterization of the interactions between each ZIKV viral protein and its host factors.     

Zika virus infection—do they also endanger male fertility?

正Zika virus(ZIKV)is a mosquito-borne flavivirus,first discovered in the 1940s.ZIKV was originally limited to sporadic cases in Africa and Asia,until the Brazil ZIKV incidences in 2015,when it rapidly spread throughout the Americas.Usually ZIKV infections are subclinical or characterized by mild febrile illness,but they may also induce neurological complications,including the rare Guillain-Barrésyndrome in adults,and congenital anomalies,     

Zika virus and neural developmental defects: building a case for a cause

正Zika virus(ZIKV),a little-known flavivirus until a few months ago,is currently at the forefront of public health concerns worldwide because of its suspected role in causing microcephaly and other developmental defects in fetuses of infected mothers.On February 1,2016,the World Health Organization declared a Public Health Emergency of International Concern(PHEIC)for ZIKV.Discovered more than     

Accidental discovery and isolation of Zika virus in Uganda and the relentless epidemiologist behind the investigations

INTRODUCTION Zika virus(ZIKV)has captured the attention of the world because of its potential to infect neural cells and its teratogenic effects on foetuses and the new born.The virus seems to have various modes of transmission and has been the subject of many reviews in the literature(example,Musso and Gubler,2016,Wang et al.,2016).ZIKV was first isolated in1947 but remained almost innocuous     

A Vesicular Stomatitis Virus-Based Vaccine Carrying Zika Virus Capsid Protein Protects Mice from Viral Infection

<正>Dear Editor,Zika virus (ZIKV) is a mosquito-borne virus that belongs to the Flavivirus family along with dengue virus (DENV),yellow fever virus, West Nile virus, and Japanese encephalitis virus (Ming et al. 2016). ZIKV is a singlestranded positive-sense RNA virus encoding three structural proteins, including nucleocapsid protein C, prM/M,envelope glycoprotein E, and seven non-structural proteins.Since 2015, over 70 countries and territories had reported     

Development and Evaluation of a Universal and Supersensitive NS1-Based Luciferase Immunosorbent Assay to Detect Zika Virus-Specific IgG

Zika virus(ZIKV) causes rash, moderate fever, conjunctivitis, and arthralgia, and has serious connection with neurological complications; therefore, it is a major threat to public health. A rapid and supersensitive method for detecting anti-ZIKV antibodies in humans and animals is thus urgently required. Here, we report an NS1-based luciferase immunosorbent assay(LISA), developed to detect ZIKV-specific IgG. Fusion proteins including a reporter Nano-luciferase(NLuc) and various fragments of ZIKV NS1 protein were expressed in 293 T cells. LISA was performed using the above cell lysates containing the expressed fusion proteins. Sample panels of humans and animals infected with ZIKV were examined for sensitivity of LISA, relative to those of ZIKV RT-PCR, commercial NS1-based ELISA, and micro-neutralization(MN) assays.Specificity and potential cross-reactivity were also evaluated using various convalescent serum samples derived from patients infected with dengue virus(DENV), Japanese encephalitis virus(JEV), and hepatitis C virus(HCV). Results indicated the optimal antigenic domain for anti-ZIKV IgG detection was located within 172–352 amino acids(aa) of ZIKV NS1 protein. NS1-based LISA performs better than commercial ELISA in anti-ZIKV Ig G detection. LISA was shown to be at least fourfold more sensitive than commercial ELISA, and could detect anti-ZIKV Ig G in various animal hosts without the need of species-specific labeled antibody. This novel assay is potentially useful for the rapid and sensitive detection of anti-ZIKV IgG in human and animal samples.     

寨卡病毒RNA恒温快速扩增检测方法的建立

2015年以来,寨卡病毒(Zika virus,ZIKV)感染被报告和小头症之间存有关联,已有多个国家和地区报告ZIKV感染证据,我国持续面对ZIKV输入风险。为发展适用于现场的快速高效的ZIKV核酸检测方法,选取ZIKV NS1片段保守区设计特异性引物探针,经优化建立了多种功能蛋白介导的ZIKV RNA恒温快速扩增检测方法。利用所制备的ZIKV NS1片段体外转录RNA作为参考品,并与实时荧光定量RT-PCR检测结果进行比较。同时利用ZIKV细胞培养物中加入健康人血清制备的模拟临床标本进行初步验证。结果显示,建立的RNA恒温快速扩增检测方法可100%检出100拷贝/μL体外转录RNA,可在15 min以内判读,大大低于PCR的常规检测时间;用该方法检测其他相关病毒,无交叉反应。病毒滴度在(10~4～10~7PFU/mL)之间的模拟临床病人标本可达到100%检出。本研究建立的ZIKV RNA恒温扩增快速检测方法快速、灵敏、特异,适用于ZIKV现场应急检测,为ZIKV的防控提供了重要的技术支撑。     

寨卡病毒引发小头症?关系越确定,防治越迫切!

自2015年初至今,寨卡病毒(Zika virus,ZIKV)以巴西为首先后在数十个国家和地区暴发流行。几乎同时,与日俱增的小头症患儿使全球对此陷入警惕状态。目前,全球正在积极探索ZIKV感染所引发的各种神经系统疾病。在越来越多证据表明在细胞水平和动物模型中ZIKV能直接损伤胚胎脑部发育的同时,ZIKV感染者的防治需求也越来越迫切。本文从ZIKV的流行病学、与小头畸形因果关系的研究进展及其预防疫苗和治疗药物的研究现状等方面进行概述。     

Serological Cross Reactivity between Zika and Dengue Viruses in Experimentally Infected Monkeys

正Dear Editor,Zika virus(ZIKV),a pathogen within the genus Flavivirus,family Flaviviridae brought an international public health emergency due to its association with neonatal microcephaly case(Platt and Miner 2017).Currently the most reliable diagnostic test is PCR detection of ZIKV RNA from body fluid samples.Unfortunately,the short viremia window and asymptomatic/mild infections greatly reduce the success rate of PCRs(de Vasconcelos et al.2018).