Novel H1N1 influenza A virus infection in a patient with acute rejection after liver transplantation

BACKGROUND:The 2009 H1N1 influenza A virus was first identified in April 2009 and rapidly evolved into a pandemic. Recipients of solid-organ transplants have a higher risk for severe infection because of immunosuppression.There are limited reports of 2009 H1N1 influenza in liver transplant recipients,especially in China. METHODS:We present a case of a 48-year-old male liver transplant recipient with 2009 H1N1 influenza A virus.He received therapy for acute rejection after transplantation and was confirmed with H1N1 virus infection. RESULTS:The patient was started on oseltamivir(75 mg, orally twice daily)and had a benign hospital course,with defervescence and resolution of symptoms within 72 hours. The follow-up chest radiograph after discharge was normal. CONCLUSIONS:The 2009 H1N1 influenza in this hospitalized transplant recipient was relatively mild,and prolonged viral shedding was not noted.Oseltamivir can be a valid measure in immunocompromised individuals.

In silico modification of oseltamivir as neuraminidase inhibitor of influenza A virus subtype H1N1

This research focused on the modification of the functional groups of oseltamivir as neuraminidase inhibitor against influenza A virus subtype H1N1.Interactions of three of the best ligands were evaluated in the hydrated state using molecular dynamics simulation at two different temperatures.The docking result showed that AD3BF2 D ligand（N-[（1S,6R）-5-amino-5-{[（2R,3S,4S）-3,4-dihydroxy-4-（hydroxymethyl） tetrahydrofuran-2-yl]oxy}-4-formylcyclohex-3-en-1-yl]acetamide-3-（1-ethylpropoxy）-1-cyclohexene-1-carboxylate） had better binding energy values than standard oseltamivir.AD3BF2 D had several interactions,including hydrogen bonds,with the residues in the catalytic site of neuraminidase as identified by molecular dynamics simulation.The results showed that AD3BF2 D ligand can be used as a good candidate for neuraminidase inhibitor to cope with influenza A virus subtype H1N1.

Close Relationship between the 2009 H1N1 Virus and South Dakota AIV Strains

Although previous publications suggest the 2009 pandemic influenza A (H1N1) virus was reassorted from swine viruses of North America and Eurasia,the immediate ancestry still remains elusive due to the big evolutionary distance between the 2009 H1N1 virus and the previously isolated strains. Since the unveiling of the 2009 H1N1 influenza,great deal of interest has been drawn to influenza,consequently a large number of influenza virus sequences have been deposited into the public sequence databases. Blast analysis demonstrated that the recently submitted 2007 South Dakota avian influenza virus strains and other North American avian strains contained genetic segments very closely related to the 2009 H1N1 virus,which suggests these avian influenza viruses are very close relatives of the 2009 H1N1 virus. Phylogenetic analyses also indicate that the 2009 H1N1 viruses are associated with both avian and swine influenza viruses circulating in North America. Since the migrating wild birds are preferable to pigs as the carrier to spread the influenza viruses across vast distances,it is very likely that birds played an important role in the inter-continental evolution of the 2009 H1N1 virus. It is essential to understand the evolutionary route of the emerging influenza virus in order to find a way to prevent further emerging cases. This study suggests the close relationship between 2009 pandemic virus and the North America avian viruses and underscores enhanced surveillance of influenza in birds for understanding the evolution of the 2009 pandemic influenza.

Morphofunctional Characteristics of Pulmonary Surfactant System and Its Effect on Immune Cells in Influenza A (H1N1) Pathogenesis

There is an annual increase of influenza-related SARI cases in winter months. Despite the high relevance of this problem, influenza pathogenesis and the role of surfactant system and its SP-A (surfactant protein A) enzyme in antiviral defense remain poorly understood. SP-A activates macrophage M1 polarization and triggers an antiviral response due to the activation of T-cells and dendritic cells. Therefore, surfactant system is an important element of infection protection and a promising therapeutic target.

甲型H1N1流感病毒HA基因的简单重复序列预测

目的:探讨应用ARIMA模型对甲型H1N1流感病毒血凝素(hemagglutinin,HA)基因简单重复序列(simple sequencerepeats,SSRs)的相对丰度和相对密度值进行预测的可行性,为防控流感流行制定措施提供科学依据。方法:应用Eviews 6.0软件对1970～2007年38条同源性相对较高的甲流H1N1流感病毒HA核苷酸序列中SSRs的相对丰度和相对密度进行拟合,建立时间序列模型,用模型对2008～2010年SSRs的相对丰度和相对密度进行预测,并用实际数据评估模型预测效果,进而预测2011年数据。结果:ARIMA模型较好地拟合了既往相对丰度和相对密度的实际序列,对2008～2010年的相对丰度和相对密度的预测也获得了较好的预测效果。结论:ARIMA模型能较好地模拟甲型H1N1流感病毒HA基因中SSRs的相对丰度和相对密度的变动趋势,可用于SSRs相对丰度和相对密度值的短期预测和动态分析。

福建省2009年甲型H1N1流感病毒NA基因特征及对达菲的耐药性

目的监测福建省甲型H1N1流感病毒NA基因的变化以及对达菲的耐药情况,为临床诊疗和疾病控制提供参考依据。方法从福建省流感监测网络中随机选取23株甲型H1N1流感病毒,经病毒核酸提取和一步法RT-PCR扩增,获得NA基因片段,双向测定核苷酸序列,分析NA基因序列和重要氨基酸位点特征。结果 23株甲型H1N1流感病毒NA片段基因与A/California/07/2009(H1N1)代表株的核苷酸序列进行比较,同源性高达98.1%以上;23株毒株NA蛋白第275位氨基酸均为组氨酸。结论随机选取的23株甲型H1N1流感病毒NA基因片段保持高度同源并且对达菲仍然敏感。随着国内外达菲耐药株的不断出现,应加强耐药性监测,为制定应对甲型H1N1流感流行措施提供参考。

2013-2014年宁夏甲型H1N1流行性感冒病毒血凝素基因变异状况及序列分析

目的了解甲型H1N1流行性感冒(流感)病毒的检测情况和血凝素(HA)基因变异情况。方法对宁夏流感监测哨点医院采集的流感样病例(ILI)标本采用RT-PCR方法进行核酸检测,对核酸检测阳性标本进行病毒分离;对甲型H1N1毒株提取病毒RNA,通过RT-PCR反应扩增HA1并测序,测定的序列利用生物信息软件进行分析。结果宁夏流感网络实验室共检测ILI标本6 122份,核酸检测阳性数917份,其中甲型H1N1498份,占54.31%,分离甲型H1N1毒株126株;变异氨基酸多数位于HA蛋白表面,其中部分位于抗原决定簇;关键位点第222位没有变化。结论 2013-2014年度,宁夏地区流行的流感毒株主要为甲型H1N1,遗传进化分析表明甲型H1N1病毒发生了一定程度的变异,造成2013-2014年在宁夏地区的再次流行。

猪流感病毒基因池中的新成员:新甲型H1N1流感病毒基因片段的存在及潜在威胁

新甲型H1N1流感病毒(2009pandemic H1N1virus,pdm/09)于2009年在人群中暴发以后,迅速在全球范围内传播,引起了21世纪的第一次流感大流行。pdm/09是由人的流感病毒、禽流感和猪流感病毒(swine influenza virus,SIV)经过重配后形成的病毒,它的基因片段已经进入了猪流感病毒当中并开始产生新的变异毒株,这些新的变异流感毒株在欧亚大陆、北美大陆及中国南部的各个地区被不断报道和发现,这表明猪源性pdm/09在人间流行后可返传给猪,成为猪流感病毒基因池中的固有组成,获得与SIV重组形成新的重配病毒的能力,并可能仍然具有感染人类的潜能。因此,必须关注新型重配病毒的进化:包括其在猪群中的生长适应、以及适应性感染人的进化过程。不仅如此,还必须加强对猪群及人群流感病毒的检测,了解重配病毒在人和猪两个种群中的进化过程。

Reduning plus ribavirin display synergistic activity against severe pneumonia induced by H1N1 influenza A virus in mice

OBJECTIVE:To investigate synergistic effect of Reduning(RDN)injection plus ribavirin against severe pneumonia induced by H1 N1 influenza A virus in mice.METHODS:We established a mouse model of severe pneumonia induced by influenza A virus by infecting Balb/c mice with CA07 virus.We randomly assigned the infected mice into four groups,and treated them with normal saline(NS group),RDN(injection,86.6 mg/kg),ribavirin(injection,66.6 mg/kg)or double Ribavirin plus RDN group,the same dosage as used in the single treatments)for 5 d.Lung index and lung pathology were recorded or calculated in terms of the curative effective.Cytokines,NOD-like receptor family pyrin domain containing 3(NLRP3)inflammasome related protein including caspase-associated recruitment domain(CARD)domain Apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),caspase-1 and NOD-like receptor family,pyrin domain containing 3(NLRP3),and reactive oxygen species were simultaneously investigated.RESULTS:RDN plus ribavirin treatment,not RDN or ribavirin alone,provided a significant survival benefit to the influenza A virus-infected mice.The combination treatment protected the mice against severe influenza infection by attenuating the severe lung injury.The combined treatment also reduced the viral titers in mouse lungs and lung index,downregulated their immunocytokine levels,including IL-1βand IL-18,and down regulated the NLRP3,especially the transcription and translation of caspase-1.Meanwhile NS group had significantly higher reactive oxygen species(ROS)expression which could was dramatically reduced by the treatment of RDN plus ribavirin.CONCLUSION:Our study showed that RDN combined with ribavirin could protect the mice,and reduce the lung immunopathologic damage caused by severe influenza pneumonia.The mechanism could be that it reduced ROS produce and inhibited NLRP3 inflammasome activation so that mainly lower the downstream inflammatory cytokines IL-1βand IL-18.

Hospitalized patients with novel influenza A （H1N1） virus infection： Shanghai, June-July 2009

Background From late May 2009, sporadic imported cases of novel influenza A （HIN1） were continuously confirmed in Shanghai, but there were few reports on its clinical presentation in China. The aim of the study was to investigate the demographic and clinical features of the laboratory-confirmed cases and the treatment with oseltamivir. Method We performed a retrospective study in the Shanghai Public Health Clinical Center （SHAPHC）, reviewing the medical records of the laboratory-confirmed patients derived from June 10 to July 20, 2009. Results A total of 156 cases were enrolled, of whom 152 had a history of recent travel. The mean age was 22.6 years and 89 cases （57.1%） were males. The most common symptoms were fever, cough, and sore throat, with children more likely to run a temperature above 38.5℃ than adults. The mean leucocyte count was 5.4×10^9/L, the mean neutrophil count 3.2×10^9/L and the mean lymphocyte count 1.4×10^9/L. Other findings included a normal range or elevated level of C-reactive protein （CRP） and glutamic-pyruvic transaminase and a normal or decreased level of prealbumin; the levels of prealbumin and CRP were significantly lower in the children than in the adults. Fifty-two patients had abnormal chest CT results, with small unilateral or bilateral pulmonary infiltrates, axillary and mediastinal lymphadenopathy and local pleural thickening, while no cases showed symptoms of hypoxia. All the patients received oseltamivir and recovered without complications, but the duration of fever and virus shedding were significantly longer in the children than in the adults. Conclusions Travel-related circulation may be an important reason for the H1N1 epidemic in the non-epidemic areas, and the virus caused mild respiratory symptoms. The infection in children was more severe in terms of prealbumin levels, temperature, the duration of fever and virus shedding. Oseltamivir was effective for H1N1, but more effective in the adults than in the children.

Influenza A pandemic （H1N1） 2009 virus infection

The clinical spectrum of the 2009 pandemic influenza A （H1N1） infection ranged from self-limited mild illness to progressive pneumonia, or even a fatal outcome. We summarize the clinical manifestations, risk factors for severe and fatal cases, pathologic findings and treatment of this disease in this paper based on current reports from different regions of the world.

Efficacy of seasonal pandemic influenza hemagglutinin DNA vaccines delivered by electroporation against aseasonal H1N1 virus challenge in mice

Prophylactic DNA vaccines against the influenza virus are promising alternatives to conventional vaccines. In this study, we generated two candidate gene-based influenza vaccines encoding either the seasonal or pandemic hemagglutinin antigen （HA） from the strains A/New Caledonia/20/99 （HIN1） （pV1AS） and A/Califorrtia/04/2009 （H1N1） （pVEH1）, respectively. After verifying antigen expression, the immunogenicity of the vaccines delivered intramuscularly with electroporation was tested in a mouse model. Sera of immunized animals were tested in hemagglutination inhibition assays and by ELISA for the presence of HA-specific antibodies. HA-specific T-cells were also measured in IFN-γ ELISpot assays. The protective efficacy of the candidate influenza vaccines was evaluated by measuring mortality rates and body weight after a challenge with 100 LD50 of mouse-adapted A/New Caledonia/20/99 （H1N1）. Mice immunized with either one of the two vaccines showed significantly higher T cell and humoral immune responses （P〈0.05） than the pVAX1 control group. Additionally, the pV1A5 vaccine effec- tively protected the mice against a lethal homologous mouse-adapted virus challenge with a survival rate of 100% compared with a 40% survival rate in the pVEH1 vaccinated group （P〈0.05）. Our study indicates that the seasonal influenza DNA vac- cine completely protects against the homologous A/New Caledonia/20/99 virus （H1N1）, while the pandemic influenza DNA vaccine only partially protects against this virus.

Epidemiology and Genotypic Diversity of Eurasian Avian-Like H1N1 Swine Influenza Viruses in China

Eurasian avian-like H1 N1(EA H1 N1)swine influenza virus(SIV)outside European countries was first detected in Hong Kong Special Administrative Region(Hong Kong,SAR)of China in 2001.Afterwards,EA H1 N1 SIVs have become predominant in pig population in this country.However,the epidemiology and genotypic diversity of EA H1 N1 SIVs in China are still unknown.Here,we collected the EA H1 N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features,and key molecular markers of these EA H1 N1 SIVs.Our results showed that EA H1 N1 SIVs distributed in nineteen provinces/municipalities of China.After a long-time evolution and transmission,EA H1 N1 SIVs were continuously reassorted with other co-circulated influenza viruses,including 2009 pandemic H1 N1(A(H1 N1)pdm09),and triple reassortment H1 N2(TR H1 N2)influenza viruses,generated 11 genotypes.Genotype 3 and 5,both of which were the reassortments among EA H1 N1,A(H1 N1)pdm09 and TR H1 N2 viruses with different origins of M genes,have become predominant in pig population.Furthermore,key molecular signatures were identified in EA H1 N1 SIVs.Our study has drawn a genotypic diversity image of EA H1 N1 viruses,and could help to evaluate the potential risk of EA H1 N1 for pandemic preparedness and response.

Mutations associated with egg adaptation of influenza A(H1N1)pdm09 virus in laboratory based surveillance in China, 2009–2016

Mutations of influenza virus associated with adaptation occurring during passage in embryonated chicken eggs could result in antigenic change or reduced vaccine effectiveness.In this study,we investigated the mutations of influenza A(H1N1)pdm09 egg isolates from the Chinese National Influenza Surveillance Network between 2009 and 2016.Thirteen mutations were identified in the hemagglutinin(HA)protein from viruses passaged in eggs,in comparing to those in cells.After scanning public database,four mutations,D127E,L191I,D222G/N and Q223R in HA1,which may alter the receptor-binding specificity,were observed frequently.Although the A(H1N1)pdm09 virus has evolved in human for nearly ten years,most egg-cultured viruses acquired one or more further mutations.Using the egg isolates for influenza surveillance requires extra caution because of these selected mutations,and their impacts on antigenicity and receptor-binding property need further evaluation.Currently,most of the influenza vaccines are produced using egg isolates,particularly in China.Thus,there is an urge to promote the establishment of an alternative influenza vaccine production platform.

Molecular characterization of H1N1 influenza A viruses from human cases in North America

Subtypes of H1N1 influenza virus can be found in humans in North America,while they are also asso-ciated with the infection of swine.Characterization of the genotypes of viral strains in human popula-tions is important to understand the source and distribution of viral strains.Genomic and protein sequences of 10 isolates of the 2009 outbreak ofinfluenza A(H1N1) virus in North America were obtained from GenBank database.To characterize the genotypes of these viruses,phylogenetic trees of genes PB2,PB1,PA,HA,NP,NA,NS and M were constructed by Phylip3.67 program and N-Linked glycosylation sites of HA,NA,PB2,NS1 and M2 proteins were analyzed online by NetNGlyc1.0 program.Phylogenetic analysis indicated that these isolates are virtually identical but may be recombinant viruses because their genomic fragments come from different viruses.The isolates also contain a char-acteristic lowly pathogenic amino acid motif at their HA cleavage sites(IPSIQSR↓GL),and an E residue at position 627 of the PB2 protein which shows its high affinity to humans.The homologous model of M proteins showed that the viruses had obtained the ability of anti-amantadine due to the mutation at the drug-sensitive site,while sequence analysis of NA proteins indicated that the viruses are still suscep-tible to the neuraminidase inhibitor drug(i.e.oseltamivir and zanamivir) because no mutations have been observed.Our results strongly suggested that the viruses responsible for the 2009 outbreaks ofinfluenza A(H1N1) virus have the ability to cross species barriers to infect human and mammalian animals based on molecular analysis.These findings may further facilitate the therapy and prevention of possible transmission from North America to other countries.

Insights from investigating the interactions of natural product inhibitors with neuraminidase of the 2009 H1N1 influenza virus

Neuraminidase(NA) plays a biologically vital role in the replication of influenza virus, and NA inhibitors(NAIs) are most widely used in the clinical anti-flu therapy. NA of 2009 H1 N1 influenza virus(09 N1) possesses a different substrate-binding cavity compared with other NA subtypes, making 09 N1 a more appropriate starting point for the discovery of potent 09 N1 inhibitors. As natural products are of great structural diversity, research on the interaction between natural NAIs and 09 N1 can throw light on the design of new structural NAIs. In this study, we, for the first time, conducted molecular docking procedure with GOLD on 10 natural inhibitors to 09 N1, and acquired their binding modes with 09 N1. The docking results showed that the active site S1 was important in the binding of NAIs to 09 N1. Then five scaffolds were extracted from these NAIs with interactions to site S1, and these could be used in the structural modification of NAIs. Besides, we found that the addition of H-bonding interaction with the active site could improve the NA inhibitory activity of NAIs, and it might be the reason why the approved NAIs showed high efficiency. Two terminal hydrophobic sites(Terminal 1 and Terminal 2) with no interactions to the approved NAI zanamivir were found in the 09 N1 active cavity, and four NAIs were first found to bind with the terminals. Till now, there are few studies on the meaning of Terminal 2 in the binding of NAI to NA, which could be a new direction for the rational design of NAIs.

Rapid detection of influenza A(H1N1)virus by conductive polymer-based nanoparticle via optical response to virus-specific binding

A recurrent pandemic with unpredictable viral nature has implied the need for a rapid diagnostic technology to facilitate timely and appropriate countermeasures against viral infections.In this study,conductive polymer-based nanoparticles have been developed as a tool for rapid diagnosis of influenza A(H1N1)virus.The distinctive property of a conductive polymer that transduces stimulus to respond,enabled immediate optical signal processing for the specific recognition of H1N1 virus.Conductive poly(aniline-co-pyrrole)-encapsulated polymeric vesicles,functionalized with peptides,were fabricated for the specific recognition of H1N1 virus.The low solubility of conductive polymers was successfully improved by employing vesicles consisting of amphiphilic copolymers,facilitating the viral titer-dependent production of the optical response.The optical response of the detection system to the binding event with H1N1,a mechanical stimulation,was extensively analyzed and provided concordant information on viral titers of H1N1 virus in 15 min.The specificity toward the H1N1 virus was experimentally demonstrated via a negative optical response against the control group,H3N2.Therefore,the designed system that transduces the optical response to the target-specific binding can be a rapid tool for the diagnosis of H1N1.

Detection and pathogenesis of a novel swine H3N2 influenza virus containing three genes from the 2009 pandemic H1N1 influenza viruses in Korea in 2015

Dear Editor,Influenza A viruses cause pandemics at an interval of approximately 10-40 years,and pigs are regarded as a＂mixing vessel＂because they are easily infected with avian and human influenza viruses（Ito et al.,1998）.According to previous studies,H3N2,H1N2,and H1N1 subtypes o（swine influenza viruses have been detected in Korean pigs （Pascua et al., 2013; Kim et al., 2014; Song et al., 2007）. Moreover, a novel H3N2 influenza virus containing the matrix （34） gene from a 2009 pandemic influenza virus was detected in Korean pigs in 2013 （Pascua et al., 2013）, an H1N2 influenza virus con- taining the internal genes from a 2009 pandemic influ- enza virus was found in Korean pigs in 2014 （Kim et al., 2014）, and an H1N1 influenza virus containing all genes from the classical swine influenza viruses was isolated from Korean pigs in 2007 （Song et al., 2007）.

Houttuynia cordata polysaccharide alleviated intestinal injury and modulated intestinal microbiota in H1N1 virus infected mice

Houttuynia cordata polysaccharide(HCP) is extracted from Houttuynia cordata, a key traditional Chinese medicine. The study was to investigate the effects of HCP on intestinal barrier and microbiota in H1N1 virus infected mice. Mice were infected with H1N1 virus and orally administrated HCP at a dosage of 40 mg×kg^(–1)×d^(–1). H1N1 infection caused pulmonary and intestinal injury and gut microbiota imbalance. HCP significantly suppressed the expression of hypoxia inducible factor-1α and decreased mucosubstances in goblet cells, but restored the level of zonula occludens-1 in intestine. HCP also reversed the composition change of intestinal microbiota caused by H1N1 infection, with significantly reduced relative abundances of Vibrio and Bacillus, the pathogenic bacterial genera. Furthermore, HCP rebalanced the gut microbiota and restored the intestinal homeostasis to some degree. The inhibition of inflammation was associated with the reduced level of Toll-like receptors and interleukin-1β in intestine, as well as the increased production of interleukin-10. Oral administration of HCP alleviated lung injury and intestinal dysfunction caused by H1N1 infection. HCP may gain systemic treatment by local acting on intestine and microbiota. This study proved the high-value application of HCP.

Clinical features of initial cases of 2009 pandemic influenza A （H1N1） in Macao, China

Background The first case of pandemic influenza A （H1N1） virus infection in Macao Special Administrative Region （SAR） of the People＇s Republic of China was documented on June 18, 2009. Subsequently, persons with suspected infection or of contact with suspected cases received screening. All the confirmed cases were hospitalized and treated with oseltamivir. Their clinical features were observed. This may help for better management for later patients and be of benefit to the government of Macao SAR to adjust its strategy to combat the pandemic influenza A （H1N1） virus infection more efficiently. Methods From June to July 2009, the initial 72 cases of influenza A （H1N1） in Macao were hospitalized in Common Hospital Centre S. Januario （CHCSJ）. The infection was confirmed by real-time reverse-transcriptase polymerase chain reaction （RT-PCR）. The clinical features of the disease were closely observed and documented. Oseltamivir was given to all patients within 48 hours after the onset of disease and maintained for 5 days. Results The mean age of the 72 patients was 21 years old. Forty of them were men and 32 were women. The median incubation of the virus was 2 days （1 to 7 days）. The most common symptoms were fever （97.2%） and cough （77.8%）. The rate of gastrointestinal symptoms including nausea, vomiting, and diarrhea was 2.8%. Fever typically lasted for 3 days （1 to 9 days）. The median time from the onset to positive results of real-time RT-PCR was 6 days （3 to 13 days）. After treatment with oseltamivir, most patients became afebrile within 48 hours. Only one aged patient with a history of glaucoma and hypothyroidism was found to have lung infiltration on chest X-ray. Conclusions The initial cases of pandemic influenza A （H1N1） virus infection in Macao SAR showed that most of the infected persons had a mild course. The virus could be detected by real-time RT-PCR within a median of 6 days from the onset. Oseltamivir was effective.