Conocimientos sobre enfermedades tipo influenza en estudiantes de Medicina de la Universidad de Guayaquil, Ecuador / Knowledge about influenza-like illnesses in medical students at Guayaquil University, Ecuador

RESUMEN Fundamento: las enfermedades tipo influenza son de fácil contagio y sus vías de transmisión difíciles de controlar si no son tratadas adecuadamente. Objetivo: determinar los conocimientos que poseen los estudiantes de pregrado y posgrado de la Facultad de Ciencias Médicas de la Universidad de Guayaquil sobre las enfermedades tipo influenza. Métodos: se realizó un estudio descriptivo transversal durante el mes de febrero de 2018. Se utilizaron métodos teóricos: análisis-síntesis e inducción-deducción, y empíricos: la encuesta en forma de cuestionario para indagar sobre el conocimiento de los estudiantes sobre la influenza. Resultados: la totalidad de ellos refirió poseer conocimientos sobre el tema. El 96,32 % de los de pregrado identificaron como más frecuentes la transmisión de tipo viral y el contagio por contacto con persona enferma; mientras en posgrado el 100 % expresó conocimientos al respecto; la complicación habitual más señalada fue la automedicación referida por el 72 % en pregrado y en el posgrado por el 57 %. En relación con las medidas preventivas, manifestaron conocerlas el 87 % y 89 % en el pregrado y posgrado respectivamente. Conclusiones: se comprobó que el grado de conocimientos sobre las enfermedades tipo influenza en cuanto a transmisión, etiología, acciones de protección y medidas preventivas en estos estudiantes de la Facultad de Ciencias Médicas de la Universidad de Guayaquil es aceptable, pero aún persisten algunas carencias identificadas en el estudio realizado.

ABSTRACT Background: influenza is an easily transmitted disease and its way of transmission is difficult to control if it is not properly treated. Objective: to determine the knowledge undergraduate and graduate students have on influenza-like disease at Guayaquil University Medical Sciences Faculty. Methods: a cross-sectional descriptive study was carried out at Guayaquil University Medical Sciences Faculty, during the month of February 2018. Theoretical methods were used: analysis-synthesis and induction-deduction, and empirical methods: the survey in the form of a questionnaire to inquire about students' knowledge on influenza. Results: all the students reported having knowledge on influenza. 96,32 % of the undergraduates identified the transmission of viral type by contact with the sick person as more frequent; in postgraduate studies 100 % expressed knowledge in this regard; the most common complication was self-medication referred by 72 % of undergraduate students in 72 % and in postgraduate students by 57 %. In relation to preventive measures, 87 % and 89 % expressed knowledge in undergraduate and postgraduate respectively. Conclusions: it was found that the degree of knowledge on the influenza-like disease in terms of transmission, etiology, protective actions and preventive measures in these students at Guayaquil University Medical Sciences Faculty is acceptable. There are still some shortcomings identified in the study carried out.

Etiología viral de las infecciones agudas del tracto respiratorio inferior en Cuba / Viral etiology of the acute infections of the lower respiratory tract in Cuba

RESUMEN Fundamento: las infecciones respiratorias agudas constituyen la causa principal de morbilidad a nivel mundial, al ser sus principales agentes etiológicos los virus respiratorios. Objetivo: determinar el papel de diferentes virus respiratorios en la causa de la infección respiratoria aguda grave durante el período mayo 2012 - junio 2013, en Cuba. Métodos: se realizó un estudio analítico transversal, el universo fueron las muestras clínicas recibidas en el Laboratorio Nacional de Referencia (LNR) de Virus Respiratorios del Instituto de Medicina Tropical Pedro Kourí (IPK) como parte de la vigilancia de las IRA de posible etiología viral, desde el 1 de mayo de 2012 y el 30 de junio de 2013. Se estudiaron 1 604 muestras procedentes de pacientes de todas las edades con manifestaciones clínicas. Para el diagnóstico se emplearon tres ensayos de TR-RCP múltiple de tipo anidado y un TR-RCP en tiempo real. Resultados: los rinovirus fueron los agentes más identificados, seguidos de los virus Influenza y del virus sincitial respiratorio. Los de mayor frecuencia en los pacientes con infección respiratoria aguda grave fueron los virus Influenza se demostró asociación significativa (OR 6,437; 95 % IC: 3,407-12,159; p=0,000) y en los pacientes <1 año se encontró también asociación con la detección del virus sincitial respiratorio; hubo correlación también en la población de 15-59 años con los virus Influenza (p=0,000). El virus Influenza B circuló entre los meses de mayo y septiembre del año 2012, mientras que el virus Influenza A (H1N1) pdm09 predominó en la circulación durante el 2013. Conclusiones: los resultados de esta investigación permiten esclarecer la contribución específica de los diferentes virus respiratorios en la causa de dicha enfermedad. Al mismo tiempo alertan a los programas nacionales la necesidad de centralizar los esfuerzos de la vigilancia en este tipo de infección para la identificación oportuna de eventos de salud inusitados por los virus Influenza.

ABSTRACT Background: acute respiratory infections are the main cause of mortality and morbidity worldwide, with respiratory viruses as main causative agents. Objective: to determine the paper of different respiratory viruses in the etiology of the severe acute respiratory infections during the period May 2012- June 2013, in Cuba. Methods: a transverse analytical study was carried out, the universe there were the clinical samples received in the National Laboratory of Reference (LNR) of Respiratory Viruses of the Institute of Tropical Medicine Pedro Kourí (IPK) as part of the alertness of the IRA of possible viral etiology, from May 1, 2012 and June 30, 2013. There were studied 1 604 samples proceeding from patients of all the ages with clinical declarations. For the diagnosis, there were used three essays of multiple TR-RCP of sheltered type and a TR-RCP in real-time. Results: rhinoviruses were the agents largely identified, followed by the Influenza viruses and the respiratory syncytial virus. The ones of bigger frequency in patients with severe acute respiratory infection were Influenza viruses demonstrating significant association (OR 6,437; 95 % CI: 3,407-12,159; p= 0,000) and in patients <1 year old it was also found association with the detection of respiratory syncytial virus; correlation was also in the population of 15-59 years with the viruses Influenza (p= 0,000). The Influenza virus B circulated mainly between the months of May and September of the year 2012, while the virus Influenza A (H1N1) pdm09 predominated during 2013. Conclusions: the results of this investigation allow explaining the specific contribution of the different respiratory viruses in the etiology of said pathology. At the same time, they alert the national programs of the need to centralize the efforts in vigilance of this type of infection to achieve opportune identification of health events unusual for the viruses Influenza.

Plasmacytoid Dendritic Cells Contribute to the Protective Immunity Induced by Intranasal Treatment with Fc-fused Interleukin-7 against Lethal Influenza Virus Infection

Developing a novel vaccine that can be applied against multiple strains of influenza virus is of utmost importance to human health. Previously, we demonstrated that the intranasal introduction of Fc-fused IL-7 (IL-7-mFc), a long-acting cytokine fusion protein, confers long-lasting prophylaxis against multiple strains of influenza A virus (IAV) by inducing the development of lung-resident memory-like T cells, called T(RM)-like cells. Here, we further investigated the mechanisms of IL-7-mFc-mediated protective immunity to IAVs. First, we found that IL-7-mFc treatment augments the accumulation of pulmonary T cells in 2 ways: recruiting blood circulating T cells into the lung and expanding T cells at the lung parenchyma. Second, the blockade of T cell migration from the lymph nodes (LNs) with FTY720 treatment was not required for mounting the protective immunity to IAV with IL-7-mFc, suggesting a more important role of IL-7 in T cells in the lungs. Third, IL-7-mFc treatment also recruited various innate immune cells into the lungs. Among these cells, plasmacytoid dendritic cells (pDCs) play an important role in IL-7-mFc-mediated protective immunity through reducing the immunopathology and increasing IAV-specific cytotoxic T lymphocyte (CTL) responses. In summary, our results show that intranasal treatment with IL-7-mFc modulates pulmonary immune responses to IAV, affecting both innate and adaptive immune cells.

Pathogenic analysis of acute lower respiratory infections and its correlation with asthma exacerbations / 天津医药

Objective To investigate the prevalence of year-round respiratory viral infection in children with lower respiratory tract infection (LRTI), and the relationship between respiratory viral infection and allergen sensitization in exacerbating asthma. Methods A total of 231 hospitalized children with acute LRTI were investigated from May 2013 to April 2014. The 5 most common respiratory viruses were isolated from nasopharyngeal aspirate using multiplex reverse transcription-polymerase chain reaction, including respiratory syncytial virus (RSV), adenovirus (AV), parainfluenza virus (PIV), influenza virus (IFV) and rhinovirus (RV). Atopic sensitization was defined if more than 1 serum specific immunoglobulin E level measured using immunofluorescence experiment was over 0.35 IU/mL. Results RSV was the most common pathogen of bronchiolitis in hospitalized children through the year. RV or IFV infections were more prevalent in asthma exacerbations compared to other LRTIs. AV was more likely to cause pneumonia. RV and IFV were associated with asthma exacerbations in children with atopic sensitization, but not in nonatopic children. Conclusion RV and IFV are associated with hospitalization for asthma exacerbation in children with atopic sensitization.

Evolutionary dynamics of highly pathogenic avian influenza A/H5N1 HA clades and vaccine implementation in Vietnam

Based on hemagglutinin (HA) and neuraminidase (NA), influenza A virus is divided into 18 different HA (H1 to H18) and 11 NA types (N1 to N11), opening the possibility for reassortment between the HA and NA genes to generate new HxNy subtypes (where x could be any HA and y is any NA, possibly). In recent four years, since 2010, highly pathogenic avian influenza (HPAI) viruses of H5N1 subtype (HPAI A/H5N1) have become highly enzootic and dynamically evolved to form multiple H5 HA clades, particularly in China, Vietnam, Indonesia, Egypt, Cambodia, and Bangladesh. So far, after more than 10 years emerged in Vietnam (since late 2003), HPAI A/H5N1 is still posing a potential risk of causing outbreaks in poultry, with high frequency of annual endemics. Intragenic variation (referred to as antigenic drift) in HA (e.g., H5) has given rise to form numerous clades, typically marking the major timelines of the evolutionary status and vaccine application in each period. The dominance of genetically and antigenically diversified clade 2.3.2.1 (of subgroups a, b, c), clade 1.1 (1.1.1/1.1.2) and re-emergence of clade 7.1/7.2 at present, has urged Vietnam to the need for dynamically applied antigenicity-matching vaccines, i.e., the plan of importing Re-6 vaccine for use in 2014, in parallel use of Re-1/Re-5 since 2006. In this review, we summarize evolutionary features of HPAI A/H5N1 viruses and clade formation during recent 10 years (2004-2014). Dynamic of vaccine implementation in Vienam is also remarked.

Inflammasomes in antiviral immunity: clues for influenza vaccine development

Inflammasomes are cytosolic multiprotein complexes that sense microbial motifs or cellular stress and stimulate caspase-1-dependent cytokine secretion and cell death. Recently, it has become increasingly evident that both DNA and RNA viruses activate inflammasomes, which control innate and adaptive immune responses against viral infections. In addition, recent studies suggest that certain microbiota induce inflammasomes-dependent adaptive immunity against influenza virus infections. Here, we review recent advances in research into the role of inflammasomes in antiviral immunity.

Prevalence of respiratory viral infection in children hospitalized for acute lower respiratory tract diseases, and association of rhinovirus and influenza virus with asthma exacerbations / 소아과

PURPOSE: In this study, we aimed to investigate the prevalence of year-round respiratory viral infection in children with lower respiratory tract infection (LRTI) and the relationship between respiratory viral infection and allergen sensitization in exacerbating asthma. METHODS: We investigated the sources for acute LRTIs in children admitted to our hospital from May 2010 to April 2011. The 6 most common respiratory viruses were isolated from nasopharyngeal aspirate using multiplex reverse transcription-polymerase chain reaction in 309 children; respiratory syncytial virus (RSV), adenovirus (AV), parainfluenza virus (PIV), influenza virus (IFV), human metapneumovirus (hMPV), rhinovirus (RV). Atopic sensitization was defined if more than 1 serum specific Immunoglobulin E level measured using UniCAP (Pharmacia) was over 0.35 IU/mL. RESULTS: RSV was the most common pathogen of bronchiolitis in hospitalized children through the year. RV or IFV infection was more prevalent in asthma exacerbations compared to other LRTIs. AV and hMPV were more likely to cause pneumonia. RV and IFV were associated with asthma exacerbations in children with atopic sensitization, but not in nonatopic children. CONCLUSION: RV and IFV are associated with hospitalization for asthma exacerbation in children with atopic sensitization.

Mixed cells in shell vials for detection of influenza viruses and enteroviruses from clinical specimens / 中华传染病杂志

Objective To evaluate shell vials of MHV,a combination of Madin-Darby canine kidney cells (MDCK),human epidermoid cancer cells (Hep-2) and African green monkey kidney cells (Vero),and conventional cell culture in detecting influenza viruses and enterovirus from fresh clinical specimens.Methods Specimens from patients with influenza-like illness and children with hand-foot-mouth disease were inoculated with both shell vials of MHV and MDCK/Vero.Then cytopathological effect (CPE) was examined daily.Influenza viruses and enteroviruses were detected by multiple reverse transcriptase-polymerase chain reaction (mRT-PCR).Results CPE of MDCK/Vero cells were stronger than the shell vials of MHV.The isolation rate of influenza virus by MHV was 24.6％ (34/138) and that by MDCK was 28.3％ (39/138),which was not significantly different (x2 =1.92,P＞0.05).That of enterovirus by MHV was 28.1％ (9/32) and that by Vero was 37.5％ (12/32),which was not significantly different (x2 =3.00.P＞0.05).Conclusions CPE in MDCK/Vero cells are easier to be observed than the shell vials of MHV.However,the shell vials of MHV are appropriate in public health emergencies,which can be used for isolation of influenza viruses and enterovirus in patients with respiratory symptoms.

Niños hospitalizados con neumonía por influenza AH1N11/2009 pandémico en un hospital de referencia de Perú / Children hospitalized with influenza pneumonia AH1N1/2009 pandemic in the INSN

Objetivos. Determinar las características clínicas y demográficas de la neumonía por el virus de influenza AH1N1/2009 pandémico en un hospital de referencia de Perú. Materiales y métodos. Se realizó un estudio serie de casos en niños hospitalizados por neumonía por influenza AH1N1/2009 pandémico en un hospital de referencia. Revisamos las historias clínicas entre los meses de junio a septiembre 2009. Todos los casos tuvieron confirmación virológica. Resultados. Se encontró 74 casos de neumonía por el virus de Influenza AH1N1/2009 pandémico (NVIp), de los cuales 50 tuvieron el diagnóstico de neumonía adquirida en la comunidad viral (NACv) y 24 con neumonía nosocomial viral (NNv) de los cuales 16 requirieron ventilación mecánica. Fallecieron 12, todos ellos con antecedentes de comorbilidad. Los casos NNv presentaron asociación estadística con mortalidad. En los casos NACv, los menores de 6 años representaron 72 por ciento (36/50). La mediana de tiempo de enfermedad fue de 5 días. Los síntomas más frecuentes fueron fiebre, tos, rinorrea. Recibieron oseltamivir el 82 por ciento. En la radiografía de tórax el 48 por ciento de los casos presentó infiltrado en parches y el 44 por ciento infiltrado intersticial en la radiografía de tórax. La proteína C reactiva (PCR) mayor a 10mg/L tuvo una asociación significativa con insuficiencia respiratoria (p <0,05). Conclusiones. Encontramos casos NNv quienes tuvieron mayor mortalidad, también los que presentaron el PCR elevado y los que presentaron condición preexistente.

ObjectiveTo determine the clinical and demographic characteristics of pneumonia with influenza virus AH1N1/2009 pandemic at the National Institute of Child. Methods. Retrospective case series in children hospitalized for influenza pneumonia pandemic AH1N1/2009 in a pediatric hospital. Reviewed the medical records between the months of June to September 2009. All cases had virological confirmation, we describe the clinical characteristics and conditions of severity. Results. A total of 74 children of pneumonia with influenza virus AH1N1/2009 pandemic (NVIp), of those 50 were community acquire pneumonia viral (NACv) and 24 pneumonia nosocomial viral (NNv), 16 required mechanical ventilation. 12 died, all had preexisting factors. NN cases showed statistical association with mortality. The most frequent factors were malnutrition, respiratory infections, congenital heart disease and neurological deficits In NACv cases the children under 6 years accounted for 72 percent (36/50). The median disease duration was 5 days. The most frequent symptoms were fever, cough, runny nose. Received oseltamivir 82 percent. The chest radiograph 48 percent of cases showed patchy infiltrates and 44 percent interstitial infiltrate on chest radiograph. Protein c reactive (CRP) more than 10mg / L was significantly associated with respiratory failure (p <0.05). Conclusions. Cases of NN found who had more mortality, even those who had the highest PCR and those with preexisting condition.

Neumonía aguda asociada a enfermedad tipo influenza en gestantes y no gestantes del Hospital Nacional de Itauguá, Paraguay / Acute pneumonia associated influenza-like illness in pregnant and nonpregnant in Itauguá National Hospital, Paraguay

Introducción: La reciente aparición y propagación mundial de la nueva cepa del virus de las gripe A H1 N1 ha resultado en la primera pandemia del siglo XXI. Las mujeres embarazadas están en mayor riesgo de contraer enfermedad severa y complicaciones por la gripe A H1N1. Objetivo: determinar la proporción de neumonía aguda de la comunidad asociada a enfermedad tipo influenza en gestantes y no gestantes y comparar las características clínicas y evolutivas en ambos grupos internadas en el Hospital Nacional. Material y métodos: diseño retrospectivo de cohortes en que se compararon 67 mujeres gestantes con 27 no gestantes con neumonía aguda de la comunidad, internadas en el Hospital Nacional durante la pandemia de julio a septiembre del 2009. Resultados: la proporción de mujeres gestantes con neumonía aguda de la comunidad fue de 67 (71,2%) y en las no gestantes 27 (28,7%), la edad media de ambos grupos fue de 27±10 años. Las mujeres no gestantes presentaron una frecuencia respiratoria superior: 27±4 vs. 24±5 (p=0,01 t Student). En resultados del hemograma y la saturación de O2 no hubo diferencias. Las mujeres gestantes presentaron en la semiología pulmonar mayor presencia de sibilancias 16 (23,8%) vs. 12 (44,4%) (RR=0,38 IC95% 0,22-0,66 p=0,02), crepitancia 28 (41,8%) vs. 15 (55,5%) (RR=0,62 IC95% p=0,01) y roncus 13 (19,4%) vs. 8 (29,6%) (RR=0,2 IC95% 0,2-1,07 p=0,08). El compromiso pulmonar predominante fue bilateral en ambas cohortes. Requirieron ingreso a terapia intensiva 25 casos (27%) de ambas cohortes, 16 gestantes (23,9%) 9 no gestantes (33,3%). La mortalidad en el grupo de gestantes fue de 6 (8,9%) vs. 5 (18,5%) en las no gestantes. Conclusión: la frecuencia de hospitalización por neumonía aguda de la comunidad asociada a enfermedad tipo influenza fue mayor en mujeres gestantes, las características clínicas y evolutivas fueron similares en ambos grupos y la mortalidad global del 11,7%.

Introduction: The emergence and global spread of the new strain of influenza virus A H1 N1 has resulted in the first pandemic of the century. Pregnant women are at higher risk for severe disease and complications from influenza A H1N1. Objective: To determine the proportion of community acquired pneumonia associated with influenza-like illness in pregnant and non pregnant woman and compare the clinical characteristics and outcome in both groups of patients admitted to the National Hospital. Material and methods: A retrospective cohort design which compared 67 pregnant with 27 non-pregnant with community acquired pneumonia , admited to the Hospital during the pandemic pediod from July to September 2009. Results: The proportion of pregnant women with community acquired pneumonia was 67 (71.2%) and 27 non-pregnant women (28.7%), the average age of both groups was 27 ± 10 years. Non-pregnant women had a higher respiratory rate 27 ± 4 vs. 24 ± 5 (p = 0.01, t test). Results of hemogram and O2 saturation did not differ. In lung semiology Pregnant women had more wheezing 16 (23.8%) vs. 12 (44.4%) (RR = 0.38 95% CI 0.22 to 0.66 p = 0.02), crepts 28 (41.8%) vs. 15 (55.5%) (RR = 0.62 95% p = 0.01) and rhonchi 13 (19.4%) vs. 8 (29.6%) (RR = 0.2 95% CI 0.2 to 1.07 p = 0.08). The predominant lung involvement was bilateral in both cohorts. Required admission to ICU 25 (27%) of both cohort, pregnant 16 (23.9%), no pregnant 9 (33.3%), mortality in the pregnant group was 6 (8.9%) vs. 5 (18.5%) in non-pregnant women. Conclusion: The frequency of hospitalization in community acquired pneumonia associated with influenza-like illness was higher in pregnant women, clinical features and outcome were similar in both groups and the overall mortality was 11.7%.

Diversidade genética dos vírus influenza A detectados em crianças de São Paulo / Genetic diversity of influenza virus A detected in children of São Paulo

Os vírus Influenza A infectam um largo espectro de hospedeiros e causam epidemias anuais. São vírus com alta variabilidade genética e RNA segmentado, que podem sofrer rearranjos entre os genes de diferentes vírus. Em 2006, foram analisadas 521 amostras de crianças menores de 5 anos atendidas no HU-USP e 25 foram positivas para Influenza A, sendo H3N2 o mais prevalente (68%). Cinco genes de 18 amostras foram seqüenciados e obtivemos 13 sequencias de HA, 12 da NP, 12 de NA, 14 da M e 10 da NS. Verificou-se a presença de várias mutações, especialmente na HA e NA, que favoreceram a substituição da cepa vacinal naquele ano. Todas as amostras H3N2 apresentaram sítios de resistências aos inibidores da M2. Diferentes linhagens circularam no mesmo ano, tanto de H1 como de H3, favorecendo rearranjos entre elas. Foram verificados, também rearranjos envolvendo os genes da HA e NP, indicando o complexo mecanismo de evolução desses vírus e enfatizando a necessidade de monitoramento da circulação e caracterização de seus genes.

Influenza A virus infects a wide range of hosts and cause annual outbreaks. RNA segmented virus has high genetic variability and may have rearrangements between the genes of different viruses. In 2006, 521 samples of children younger than 5 years were analyzed and 25 tested positive for Influenza A virus, of which the subtype H3N2 is the most prevalent (68%). Five genes of 18 samples were sequenced and 13 sequences of HA, 12 of NP, 14 of M and 10 of NS obtained were. The presence of this several mutations, especially in the HA and NA genes probably helped the replacement of the vaccine strain in that year. All H3N2 subtype samples showed points of resistance to M2 inhibitors. The phylogenetic analysis revealed the circulation of different lineages in the same year, for both H1 and H3, and the presence of two rearrangements involving the HA and NP genes. These results indicate the influence of rearrangements in the evolution of the virus and emphasize the need for monitoring of circulation and characterization of genes.

Reverse genetic platform for inactivated and live-attenuated influenza vaccine

Influenza vaccine strains have been traditionally developed by annual reassortment between vaccine donor strain and the epidemic virulent strains. The classical method requires screening and genotyping of the vaccine strain among various reassortant viruses, which are usually laborious and time-consuming. Here we developed an efficient reverse genetic system to generate the 6:2 reassortant vaccine virus from cDNAs derived from the influenza RNAs. Thus, cDNAs of the two RNAs coding for surface antigens, haemagglutinin and neuraminidase from the epidemic virus and the 6 internal genes from the donor strain were transfected into cells and the infectious viruses of 6:2 defined RNA ratio were rescued. X-31 virus (a high-growth virus in embryonated eggs) and its cold-adapted strain X-31 ca were judiciously chosen as donor strains for the generation of inactivated vaccine and live-attenuated vaccine, respectively. The growth properties of these recombinant viruses in embryonated chicken eggs and MDCK cell were indistinguishable as compared to those generated by classical reassortment process. Based on the reverse genetic system, we generated 6 + 2 reassortant avian influenza vaccine strains corresponding to the A/Chicken/Korea/MS96 (H9N2) and A/Indonesia/5/2005 (H5N1). The results would serve as technical platform for the generation of both injectable inactivated vaccine and the nasal spray live attenuated vaccine for the prevention of influenza epidemics and pandemics.

Analysis of haemagglutinin gene of the first influenza A-H1N1 viral strain isolated in Guangdong Province during an influenza A pandemic in 2009 / 中华传染病杂志

Objective To detect and analyze the haemagglutinin (HA) gene of the first influenza A-H1N1 viral strain isolated in Guangdong Province during an influenza A pandemic in 2009.Methods A-H1N1 virus strain was isolated from the throat swab of the first patient diagnosed with A-H1N1 virus infection in Guangdong Province in 2009. Viral nucleonic acid was extracted from supernatant of cell culture and amplified using reverse transcriptase-polymerase chain reaction (RT-PCR) with HA gene-specific primers. The product was cloned, sequenced, and the homology was analyzed. Results A 1710 bp HA gene of the first influenza A-H1N1 viral strain in Guangdong Province in 2009 was acquired, which was named as A/GuangzhouSB/01/2009 (H1N1) HA with GenBank access No. GQ268003. The homology of the studied HA gene and the 277 influenza A (H1N1) isolates reported in the epidemic areas was 99.0%-99.8%, and as high as 99.8% when compared with the isolates reported in the United States where the patient had traveled. When the studied HA gene was compared with 25 isolates of Chinese seasonal A-H1N1 virus, the homology was 72.3%-85.6%. Conclusions The homology of the first isolated A-H1N1 viral strain in Guangdong Province in 2009 and epidemic influenza A-H1N1 virus is high, while it is low compared with Chinese seasonal A-H1N1 virus.

Establishment of plaque reduction assay and its application in the susceptibility testing against influenza virus in vitro / 中华检验医学杂志

Objective To establish plaque reduction assay and evaluate the activities of oseltamivir (tamiflu),amantadine,ribavirin and herb radix isatidis against influenza virus in vitro.Methods Plaque reduction assay was used to determine IC_(50) values of four studied drugs above in this susceptibility testing in which 8 clinical isolates(three influenza A virus isolates and five influenza B virus isolateds)were inoculated and tested.Results By testing of 8 clinical isolates of influenza virus A and B isolated between the year 2001 to 2008,oseltamivir and amantadine were found to be sensitive to influenza A virus with IC_(50) of 0.064 -0.128 mg/L and 0.5 mg/L,respectively.However,ribavirin(IC_(50)>8 mg/L)was not found to be sensitive,and herb radix isatidis had totally no activities.Unfortunately.all four studied drugs were not found to have activities against influenza B virus in vitro.Conclusions It Was indicated that oseltamivir and amantadine.but not ribavirin and herb radix isatidis.are sensitive to influenza A virus.All four studied drugs were not found to have activities against influenza B virus in vitro.

Detection of respiratory viruses from patients with influenza like illness in Guangzhou using centrifugation-enhanced shell vials method between January and June, 2009 / 中华检验医学杂志

Objective To evaluate the application of high-throughput shell vial assay in a clinical laboratory for detection of respiratory viruses from patients with ILI in Guangzhou between January and June, 2009. Methods Six hundred and fifty-two pharyngeal swab specimens were taken from ILI patents. Centrifugation-enhanced shell vials including 4 cell lines (MDCK, Hep-2, LLC-MK2 and MRC-5) were used for culture of respiratory viruses for 2-3 days. The cultures were identified by observation of cytopathic effect (CPE) , hemmaglution or hemmadsorption test as well as immunofluorescence staining. Results A total of 161 swab samples (24.69% ,161/652) were shown to have any one of the 5 common respiratory viruses including influenza A viruses ( 38. 51% , 62/161 ), influenza B virus ( 54. 65% , 88/161 ), parainfluenza viruses (4. 96% , 8/161 ) , adenovirus ( 1. 24% , 2/161 ), and respiratory syncytial virus (0. 62% ,1/161). The turnaround time was 2d for influenza viruses, 3d for adenovirus and parainfluenza viruses respectively. Conclusions (1) The shell vial method was effective, rapid and high throughout for the detection of respiratory viruses in clinical laboratories.(2)Influenza viruses were dominant in the swab samples from patients with ILI in Guangzhou between January and June with the highest appearance in the summer influenza B vires was the most common pathogen in patients with ILI in this study.

Multiplex RT-PCR assay for the detection of 8 kinds of respiratory viruses / 中华检验医学杂志

. Conclusions Two multiplex RT-PCR assays show high consistency with common RT-PCR. The multiplex RT-PCR assays were initially established.

Virological surveillance and variability of influenza viruses in Hebei,2005～2006 / 中华疾病控制杂志

N)compared with B/HongKong/330/2001.Conclusions H1,H3 and B virus were circulated in Hebei from 2005 to 2006.Recent viruses were changing in genetic characteristics,while influenza B viruses varied more obviously.

Surveillance of hemagglutinin genetic variation of influenza viruses in Shanghai and Wuxi / 中华传染病杂志

Objectives To explore the type and subtype distribution of influenza viruses in influenza-like patients and the hemagglutinin(HA)genetic variation of influenza A viruses in Shang- hai and Wuxi during the influenza prevalent season from 2004 to 2006.Methods Throat swabs were collected from the influenza-like patients in the sentinel hospitals and during the outbreaks,and then inoculated into MDCK cells to isolate influenza viruses,which were subsequently identified by direct immunofluorescence(DIF)and reverse transcription-polymerase chain reaction(RT-PCR).HA seg- ments of influenza A viruses were sequenced to analyze the genetic variation of HA.Results One hundred and twenty-six strains of influenza viruses,including 53 H3N2,43 H1N1 and 30 influenza B viruses were isolated from August 2004 to September 2006,and 7 outbreaks.All these outbreaks oc- curred in February or March The pathogens were identified as H1N1 in one outbreak,H3N2 in two outbreaks,B in two outbreaks and mix infections in two outbreaks(1 H1N1 and B,1 H3N2 and B, respectively).By sequencing the HA segment,the H3 and H1 segments were all homologous to the isolates from different countries in the same period.Conclusion H3N2 and H1N1 are the major strains prevalent in Shanghai and Wuxi,which reach the peak from January to March No HA and NA recom- binant strains and new HA and NA subtypes are found in these areas.The variations of H1 and H3 are similar to those found in other countries.

The effects of mutant influenza nonstructural protein 1 to IRF-3 / 中华传染病杂志

Objective To explore the inhibitory effect of mutant influenza A viruses to the activation of interferon regulatory factor 3 (IRF-3). Methods HEK293 cells were infected with A/FM/1/47,A/HK/1/68, A/HK/1/68-MA20, A/HK/1/68-MA20C and positive control Sendai virus (SV). Whether the slowly moved phosphorylation form Ⅲ and Ⅳ of IRF-3 appeared or not was compared by Western blot in cells infected with these viruses. Wild type of NS1 from A/HK/1/68 and mutant NS1 from A/HK/1/68-MA20 were subcloned into pcDNA3.1-flag respectively. They were transfected in HEK 293 cells respectively. At 16 hours posttransfection, cells were infected with Sendai virus for 8 hours. Whole cell extracts were analyzed by Western blot and then probed with monoclonal flag antibody to check the expression of NS1, or with anti-IRF-3 to observe the inhibitory effects of the wild and mutant NS1 to the activated IRF-3. Luciferase assay was carried out by co-transfection with reporter plasmid, pGL2B with interferon ? promoter, and wild or mutant NS1 cDNA expression plasmid. SV was used to infect these cells after the co-transfection. Results Only less virulent A/HK/1/68-MA20 and positive control SV can activate IRF-3. Activated form Ⅲ and Ⅳ of IRF-3 began to appear 9 hours post infection (h.p.i), and most significant activated IRF-3 appeared 23 and 26 h.p.i. Sequence analysis of NS1 of MA20 revealed that nucleotide position number 94 is mutated from T to C, and amino acid at position number 23 is changed from valine to alanine. Co-transfected with wild type NS1 made form Ⅲ and Ⅳ of IRF-3 almost disappear, but not mutant NS1. In the luciferase functional analysis, wild type NS1 can inhibit the luciferase activity of IFN-? promoter, which was induced by SV, to around 1/10. Again no inhibitory effects was observed of mutant NS1 in the luciferase assay. Conclusion The mechanism that A/HK/1/68-MA20 can activate IRF-3 is that point mutant NS1 abolished the inhibitory function of NS1.