Ultrastructural characterization of avian influenza A(H7N9) virus infecting humans in China

Dear Editor,In March 2013,the first 3 cases of severe disease dueto a novel avian-origin influenza A(H7N9)virus weredetected in the Chinese provinces of Shanghai and Anhui(Gao R,et al.,2013).A total of 339 laboratory-confirmedcases with 100 deaths were reported until January 142014(WHO,2014).To the best of our knowledge,thisis the first time that human infection with the avian in-fluenza A H7N9 subtype has been detected.Prior to

Morphology and structural dynamics of amyloid beta 42 assembly in vitro

Amyloid β42 （Aβ42） aggregation plays a key role in the pathogenesis of Alzheimer＇s disease. However, the morphology and structural dynamics in different stages of Aβ42 assembly are not well known. To investigate the dynamic properties of morphological and structural changes in the aggregation process of Aβ in vitro, transmission electron microscopy, western blot analysis and circular dichroism were used to observe the changes in morphology, immunoreactivity and secondary structure during Aβ aggregation, respectively. Results demonstrated that at 24 hours following Aβ42 aggregation in vitro, the structures of spherical granules from 5 to 10 nm and coils from 20 to 30 nm were visualized by transmission electron microscopy. Different immunoreactivities of the oligomers and fibers were detected by western blot analysis. The dynamic changes of the α-helix to β-sheet were confirmed by circular dichroism spectra. The dynamic properties of the morphological and structural changes in the aggregation process of Aβ42 in vitro were analyzed, which contributed to the identification of stable conditions of Aβ42 oligomer formation.

Preparation and immunoprotective effects of a virus-like particle candidate vaccine of the dominant epidemic D3 genotype coxsackievirus A6 in China

Coxsackievirus A6 of the D3a genotype(CVA6 D3a)is a primary pathogen causingmainland of China's hand,foot,and mouth disease(HFMD).Viral‐like particle(VLP)vaccines represent a potential candidate vaccine to prevent HFMD.This study collected Anti‐CVA6 D3a VLPs serum from BALB/c female mice immunized using CVA6 D3a VLPs.The neutralizing antibody levels were compared against the representative 14‐JX2018(D3a)and N4‐YN2015(D3b)strains between the antisera of different immune pathways.The immunoprotective effect of anti‐CVA6 D3a VLPs against these strains was monitored using pathological sections and immuno-histochemical results of lung and skeletal muscle tissues in seven‐day‐old Institute of Cancer Research(ICR)mice.Immunological protection against different branches of viruses was evaluated in 7‐day‐old(serum passive immune protection)and 14‐day‐old(VLPs active immune protection)neonatal ICR mice models.Serum‐neutralizing antibody levels were positively correlated with the number of immunizations and higher against 14‐JX2018 than against N4‐YN2015.Furthermore,these levels were significantly higher with abdominal injection than intramuscular injection.The immunized serum of 7‐day‐old ICR mice inoculated three times was 100%protected against CVA6 D3a 14‐JX2018(lethal titer:106.25 TCID 50)and CVA6 D3b N4‐YN2015(lethal titer:105.25TCID 50)fatal attacks,respectively.For ICR mice that have completed two active immunizations for 14 days,both CVA6 D3a 14‐JX2015(challenge titer:108.25 TCID 50)and CVA6 D3b N4‐YN2015(challenge titer:107.25 TCID 50)were used for the challenge,and the mice were able to survive.Overall,the CVA6 D3a VLPs prepared in this study are a potential vaccine candidate for CVA6,as it has the optimal protective effect against both CVA6 D3a and D3b evolutionary branches viruses.

导致狐狸重症腹泻疫情的新型犬冠状病毒的发现与鉴定

2019年末,中国东北地区狐狸群中暴发大规模疫情,发病狐狸表现出急性腹泻症状,并出现大量狐狸死亡.通过对该疫源地发病狐狸肛拭子、血液与发病组织的检测分析,获得了多条全长新型犬冠状病毒(CCoV)基因组序列,研究团队将该病毒命名为VuCCoV,并确认VuCCoV是引起该疫情的病原.进一步分析表明,VuCCoV基因组的4个结构基因(S,E,M,N)中的3个(E,M,N)与犬冠状病毒(CCoV)对应基因具有超过90%的核苷酸同一性,但S基因核苷酸序列表现出较大的差异.VuCCoV的RNA依赖的RNA聚合酶与蝙蝠冠状病毒PB025的对应蛋白仅存在2~3个氨基酸差异,系统进化分析提示VuCCoV很可能来源于蝙蝠.表面等离子体共振分析实验表明,VuCCoV刺突蛋白受体结合区(RBD)可与犬和狐狸的氨肽酶N(APN)结合,但不与人APN结合,假病毒感染及病毒分离培养实验进一步证实该VuCCoV不易感染人源细胞.蝙蝠等野生动物宿主的病毒跨物种传播对人类和家畜健康构成了显著威胁,VuCCoV的发现和溯源证实蝙蝠作为疫情出现的潜在驱动因素的重要性.积极监控蝙蝠及其他犬科动物中的病毒感染,发现、鉴定对人兽健康构成潜在威胁的新型冠状病毒并研究其进化变异特征与感染特性,对于防控新发人兽共患传染病、建设国家生物安q全体系具有重要意义.

The genomic characteristics and pathogenicity of a mammalian orthoreovirus within a new lineage from wild pika in plateau

Emerging and re-emerging viruses from wild animals have seriously threatened the health of humans and domesticated animals in recent years.Herein,we isolated a new mammalian orthoreovirus(MRV),Pika/MRV/GCCDC7/2019(PMRV-GCCDC7),in the Qinghai-Tibet Plateau wild pika(Ochotona curzoniae).Though the PMRVGCCDC7 shows features of a typical reovirus with ten gene segments arranged in 3:3:4 in length,the virus belongs to an independent evolutionary branch compared to other MRVs based on phylogenetic tree analysis.The results of cellular susceptibility,species tropism,and replication kinetics of PMRV-GCCDC7 indicated the virus could infect four human cell lines(A549,Huh7,HCT,and LoVo)and six non-human cell lines,including Vero-E6,LLCMK2,BHK-21,N2a,MDCK,and RfKT cell,derived from diverse mammals,i.e.monkey,mice,canine and bat,which revealed the potential of PMRV-GCCDC7 to infect a variety of hosts.Infection of BALB/c mice with PMRVGCCDC7 via intranasal inoculation led to relative weight loss,lung tissue damage and inflammation with the increase of virus titer,but no serious respiratory symptoms and death occurred.The characterization of the new reovirus from a plateau-based wild animal has expanded our knowledge of the host range of MRV and provided insight into its risk of trans-species transmission and zoonotic diseases.

The First Imported Case of Monkeypox in the Mainland of China—Chongqing Municipality,China,September 16,2022

Monkeypox is a zoonotic viral disease caused by the monkeypox virus(MPXV),and historically,all outbreaks have been linked to Africa;however,monkeypox has been posing an alarming challenge to the world in 2022(1)as approximately 60,000 cases have been reported in more than 100 nations and regions worldwide(2).Currently,many cases of monkeypox were identified in many nonendemic countries outside of Central and West Africa,and human-to-human transmission has occurred frequently,especially among men who have sex with men(MSM)presenting new clinical symptoms similar to syphilis and other sexually transmitted infections(3).

Long Distance Transmission of SARS-CoV-2 from Contaminated Cold Chain Products to Humans——Qingdao City,Shandong Province,China,September 2020

Summary What is already known about this topic?Though coronavirus disease 2019(COVID-19)has largely been controlled in China,several outbreaks of COVID-19 have occurred from importation of cases or of suspected virus-contaminated products.Though several outbreaks have been traced to severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)isolated on the outer packaging of cold chain products,live virus has not been obtained.

Isolation of 2019-nCoV from a Stool Specimen of a Laboratory- Confirmed Case of the Coronavirus Disease 2019 (COVID-19)

The novel coronavirus(2019-nCoV)is spreading very fast in Hubei Province of China.As of February 14,2020,51,986 confirmed cases(including laboratory-confirmed cases and clinically-confirmed cases)were reported in Hubei Province,and 1,318 of them died.Respiratory droplets and contact transmission are considered to be the most important routes of transmission of 2019-nCoV,but do not fully account for the occurrence of all coronavirus disease 2019(COVID-19)cases,previously known as novel coronavirus pneumonia(NCP),and the reasons for the rapid spread of this virus(1).

Isolation and Characterization of Monkeypox Virus from the First Case of Monkeypox—Chongqing Municipality,China,2022

Introduction:The first imported case of monkeypox(MPX)from the mainland of China was reported in September 2022.Herein,the study reports the isolation and characterization of MPX virus(MPXV)in this case.Methods:Clinical specimens including skin blister fluid,oropharyngeal and nasopharyngeal swabs,and blood were collected and inoculated onto Vero cells.The isolated virus was identified as MPXV using quantitative polymerase chain reaction(qPCR),cytopathic effects(CPEs),immunofluorescence assay(IFA)and transmission electron microscopy(TEM).Plaque assays were employed to quantify infectious plaque-forming units(PFUs).The plaque reduction neutralization test(PRNT)was developed to determine the neutralizing antibody(nAb)against MPXV.Results:MPXV replication was confirmed with qPCR.Typical CPEs were observed 48 h postincubation.The isolated virus was named MPXV-B.1-China-C-Tan-CQ01.IFA showed that MPXV reacted with serum of MPX case.Orthopoxvirus morphology was observed using TEM.The virus titer increased to>106 PFU/mL after three passages.The serum PRNT 50%neutralization titer(NT50)was 35 for the MPX patient 6 days after symptom onset.Discussion:The study successfully isolated the first MPXV strain in the mainland of China,MPXV-B.1-China-C-Tan-CQ01.Infectious titration and PRNT methods have been developed.The study provides key resources and technical platforms for further research as well as anti-viral drug and vaccine development against MPX.

Effects of solid friction modifier on friction and rolling contact fatigue damage of wheel-rail surfaces

In railway network,friction is an important factor to consider in terms of the service behaviors of wheel-rail system.The objective of this study was to investigate the effect of a solid friction modifier(FM)in a railway environment.This was achieved by studying the friction,wear,and rolling contact fatigue(RCF)damage on the wheel-rail materials at different slip ratios.The results showed that when a solid FM was applied,the friction coefficient decreased.After the solid FM was separated from the wheel-rail interface,the friction coefficient gradually increased to its original level.With the application of the solid FM,the wear rates of the wheel-rail decreased.In addition,the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced.The worn surfaces of the wheel-rail were dominated by pits and RCF cracks.Without the FM,RCF cracks ranged from 84 to 120μm,and subsurface cracks were generated.However,with the FM,RCF cracks ranged from 17 to 97μm and no subsurface cracks were generated.These findings indicate possible methods of improving the performance of railway rolling stock by managing friction,and reducing wear and permanent RCF damage affecting both the wheels and rails.

Description of the First Strain of 2019-nCoV,C-Tan-nCoV Wuhan Strain-National Pathogen Resource Center,China,2020

The recent outbreak of novel coronavirus-infected pneumonia(NCIP)in China(1)has attracted much attention domestically and internationally.As the outbreak occurred,China carried out emergency responses quickly,notified the World Health Organization(WHO)in a timely manner,and shared the viral gene sequence with international communities immediately after pathogenic identification.

Genetic and Phylogenetic Characterization of a Chikungunya Virus Imported into Shenzhen, China

Dear Editor,Chikungunya virus(CHIKV)is a mosquito-borne virus belonging to the family Togaviridae,genus Alphavirus,and was first isolated in Tanzania in the 1950s(Silva and Dermody 2017;Weaver and Lecuit 2015).Human infections with CHIKV typically result in a rapid-onset febrile disease,with symptoms that include fever,headache,rash,severe joint and muscle pain,as well as prolonged periods of disability in some patients(Weaver and Lecuit 2015;Silva and Dermody 2017).

Identification of Histoplasma causing an unexplained disease cluster in Matthews Ridge, Guyana

Here,we report the identification of Histoplasma causing an unexplained disease cluster in Matthews Ridge,Guyana.In March 2019,14 employees of Chongqing Bosai Mining Company,China,working in a manganese mining of Guyana,had unexplained fever,and two of them died.We obtained lung and brain tissues as well as the blood samples from the two deceased cases(patient No.1 and 2),and bronchoscopy lavages and cerebrospinal fluid samples from one severe case(patient No.3),respectively.All samples were tested by pathological examination,high-throughput sequencing,and real-time PCR.Pathological detection showed the presence of spore-like structures in the lung tissue of patient No.1,indicating a fungal infection in this patient.Nanopore sequencing identified the existing of H.capsulatum in the lung tissue sample within 13 h.Next-generation sequencing identified specific fragments of H.capsulatum in all of the samples tested(lung,brain and blood serum from the deceased cases,and plasma from the severe case).Real-time PCR assays did not reveal any viral infection related to transmission from bat feces.We conclude that H.capsulatum was the causative pathogen of this disease cluster based on epidemiologic,clinical,pathological and nucleic acid evidence.

Seroprevalence of Wenzhou virus in China

Wenzhou virus(WENV)was first identified in rodents and Asian house shrews in Wenzhou,Zhejiang Province,China.However,little is known about the prevalence of WENV infections in humans in China.To determine the threat that WENV may pose to humans,we determine the seroprevalence of WENV in healthy individuals in China in this study.Cross-reactivities of nucleoprotein(NP)were detected between Lymphocytic choriomeningitis virus(LCMV)and WENV using Western blot and ELISA assy.The prevalence of specific IgG antibodies against WENV NP was investigated in different age groups of 830 healthy individuals aged 0-70 years old in China using a competition ELISA assay.The results indicate that WENV and LCMV share cross-reactive epitopes between NPs.The total seroprevalence of WENV in healthy adults was 4.6%,with 3.6%(8/221)for individuals 15-44 years of age,5.4%(17/317)for individuals 45-59 years of age,and 4.1%(4/98)for older adults over 60.The total seroprevalence of WENV in children under age 15 was 1.5%,with 2.9%(1/34)in children aged 2-5 years,and 2.2%in 5-14 years(2/91).The finding suggests that WENV or WENV-like virus may sporadically infect humans of China.

Parallel isolation of calicivirus and reovirus from lethal co-infected mink during a potential epidemic of farmed mink infections

Mink has been identified as an animal with susceptibility to SARS-CoV-2 and also as the only animal with evidence to transmit the virus back to humans.Thus,the surveillance of viruses among high-density farmed minks has a significant meaning for the control of zoonotic emerging diseases in humans.Within anal swabs of minks that died of unknown causes in a mink farm,mink calicivirus(MCV)and mammalian orthoreovirus(MRV)were detected and simultaneously observed within MDCK cell culture from the sample of the same lethal mink.The parallel isolation was successfully performed by utilizing cell lines from different host sources with distinct viral sensitivities,i.e.Mv.1.Lu and Vero-E6 and the two viruses were independently separated.The prevalence of the virus among the minks and its genomic characteristics were investigated through deep sequencing technology.Phylogenetic analysis of the viral genome showed a close relationship of the newly isolated MCV-GCCDC8-2020 with MCV strains belonging to the genus Vesivirus,but with unique mutations derived from the major structural protein(VP1).The reovirus MRV-GCCDC9-2020 isolated from the same mink belongs to serotype 3 mammalian orthoreovirus and genome analysis showed a potential reassortment derived from reoviruses in different species.This study provides a beneficial reference on viral co-infection within disease investigation in farmed minks and raises the concern for the virus surveillance among the high-density fed animal farms.

Structural changes of a bacteriophage upon DNA packaging and maturation

Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).

The first strain of monkeypox isolated in the Chinese Mainland and preserved at the National Pathogen Resource Center of China

On September 16,2022,the first imported monkeypox case was reported in the Chinese Mainland.Laboratory tests including nucleic acid detection were carried out in Chongqing Nan’an Centre for Disease Control and Prevention and Chongqing Center for Disease Control and Prevention.After that,monkeypox virus was isolated by the Institute for Viral Disease Control and Prevention and preserved at the National Pathogen Resource Center on September 18,2022.The National Pathogen Resource Center shared the basic information of monkeypox virus strain,samples,biosafety,strain imaging,RT-PCR primers,and probes sequence timely to support the prevention and control of monkeypox epidemic and facilitate the scientific research on vaccine development,drug screening and evaluation of monkeypox virus in the future.

Significant Spike-Specific IgG and Neutralizing Antibodies in Mice Induced by a Novel Chimeric Virus-Like Particle Vaccine Candidate for Middle East Respiratory Syndrome Coronavirus

Dear Editor, Middle East respiratory syndrome coronavirus (MERSCoV),first isolated in 2012,has emerged zoonotically among humans (van Boheemen et al.2012).Since then, MERS-CoV continues to be a public health concern,with a fatality rate of 35%.On-going MERS-CoV outbreaks highlight the urgent need for the development of interventional measures,including an effective vaccine against MERS-CoV infection.Currently,no licensed therapeutic or vaccine is available (Okba et al.2017).