Molecular and serological investigations of the Influenza A(H1N1) 2009 pandemic virus in Turkey.

Intense research has been conducted on influenza A(H1N1)pdm09 virus to determine the virulence markers. Limited information on characteristics of pandemic virus has become available in Turkey since the pandemic. In this first report from Turkey, we investigated the molecular markers that have been associated with increased virulence and oseltamivir resistance. We also conducted serological studies in people after infection, vaccination, exposure, and no-exposure controls to determine the level of protection against the pandemic H1N1 influenza virus. Thirteen rRT-PCR positive samples were analyzed for presence of mutations that have been associated with host range, virulence, and antiviral resistance: substitution D222G in the HA, E627K in the PB2, and H275Y in the neuraminidase (NA). In addition, 135 serum samples from vaccinated, recovered, asymptomatic contacts, and control individuals were tested using hemagglutination inhibition (HI) assay. D222G was detected in nasal samples from two severe cases. No specified mutations in the PB2 and NA were identified. Additional substitutions, I216V, V321I, E374K, S203T in HA, V655I in PB2, and I163V in NA, were detected. HI testing from vaccinated individuals, recovered patients, asymptomatic contacts, and control individuals showed that 97.9, 99.7, 88.2, and 44.2 % had HI titers ≥40, respectively. Molecular markers promoting influenza A(H1N1)pdm09 to become a pandemic virus are still under investigation. Serological results confirm that younger, un-exposed individuals are at increased risk of pandemic virus infections. Influenza A(H1N1)pdm09 viruses are still in circulation around the globe. Therefore, these viruses need to be monitored closely for development of new markers including antiviral resistance mutations.

[Influenza surveillance in nine consecutive seasons, 2003-2012: results from National Influenza Reference Laboratory, Istanbul Faculty Of Medicine, Turkey]. / 2003-2012 Yillarini Kapsayan Dokuz Sezonda Grip Sürveyansi Bulgulari: Istanbul Tip Fakültesi Ulusal Influenza Referans Laboratuvari Sonuçlari

Influenza is a public health problem that affects 5-20% of the world population annually causing high morbidity and mortality especially in risk groups. In addition to determining prevention and treatment strategies with vaccines and antivirals, surveillance data plays an important role in combat against influenza. Surveillance provides valuable data on characteristics of influenza activity, on types, sub-types, antigenic properties and antiviral resistance profile of circulating viruses in a given region. The first influenza surveillance was initiated as a pilot study in 2003 by now named National Influenza Reference Laboratory, Istanbul Faculty of Medicine. Surveillance was launched at national level by Ministry of Health in 2004 and two National Influenza Laboratories, one in Istanbul and the other in Ankara, have been conducting surveillance in Turkey. Surveillance data obtained for nine consecutive years, 2003-2012, by National Influenza Reference Laboratory in Istanbul Faculty of Medicine have been summarized in this report. During 2003-2012 influenza surveillance seasons, a total of 11.077 nasal swabs collected in viral transport medium were sent to the National Influenza Reference Laboratory, Istanbul for analysis. Immun-capture ELISA followed by MDCK cell culture was used for detection of influenza viruses before 2009 and real-time RT-PCR was used thereafter. Antigenic characterizations were done by hemagglutination inhibition assay with the reactives supplied by World Health Organization. Analysis of the results showed that influenza B viruses have entered the circulation in 2005-2006 seasons, and have contributed to the epidemics at increasing rates every year except in the 2009 pandemic season. Influenza B Victoria and Yamagata lineages were cocirculating for two seasons. For other seasons either lineage was in circulation. Antigenic characterization revealed that circulating B viruses matched the vaccine composition either partially or totally for only three seasons. Influenza A(H1N1) and A(H3N2) subtypes were in circulation since the beginning of the surveillance in 2003-2004 season either alone or in cocirculation. After the 2009 pandemic, A(H1N1) viruses were replaced by A(H1N1)pdm09. A(H1N1) and A(H1N1)pdm09 viruses matched the vaccine composition for all seasons. However, A(H3N2) viruses matched the vaccine composition in only three out of eight seasons. Analysis of the data revealed that, (a) influenza season has extended in Turkey and it lasts through May; (b) influenza peaks in different age groups depending on the season; (c) every year a different influenza type and subtype dominates the season; (d) influenza B has been circulating with increasing rate especially in the past six seasons. Influenza surveillance provides valuable data that can guide policy makers in developing programmes to prevent and reduce influenza burden. Therefore, addition of hospital based surveillance to general practice based sentinel surveillance will take influenza surveillance one step ahead in meeting the need for collecting data on severe influenza cases which will allow assessment of burden of influenza more reliably.

Viral etiology in hospitalized children with acute lower respiratory tract infection.

This study was performed to investigate the viral etiological agents, age distribution and clinical manifestations of lower respiratory tract infection (LRTI) in hospitalized children. The viral etiology and clinical findings in 147 children (1 month to 5 years of age) hospitalized with acute LRTI were evaluated. Cell culture was used for isolation of influenza viruses and direct fluorescent antibody assay for parainfluenza viruses (PIVs), respiratory syncytial virus (RSV) and adenoviruses (ADVs). Reverse-transcriptase polymerase chain reaction was employed for human metapneumovirus (hMPV). One hundred and six of all patients (72.1%) were male, and 116 children (79.8%) were < or = 2 years. A viral etiology was detected in 54 patients (36.7%). RSV was the most frequently isolated (30 patients, 55.6%), and PIV (27.8%), hMPV (13%), influenza-A (9.3%), and ADV (5.6%) were also shown. Dual infection was detected in six patients. There were no statistically significant differences between the two groups (with isolated virus or no known viral etiology) with respect to symptoms, clinical findings, laboratory work-up, or radiological data. Length of hospital stay was also not different. Determination of the etiology of acute LRTI in children less than 5 years of age seems impossible without performing virological work-up, whether viral or nonviral in origin.

Active Surveillance of Influenza A and Other Respiratory Viruses in Children with Influenza-like-illness in Two Seasons.

INTRODUCTION: The aim of this study was to asses the surveillance of influenza A/other respiratory viruses and risk factors in hospitalized children with the symptoms of influenza-like illness during two consecutive influenza seasons. METHODOLOGY: All children hospitalized with adiagnosis of influenza-like illness had been investigated for Influenza A and other respiratory antigens in pharengeal/nasopharyngeal secretions. RESULTS: A total of 132 hospitalized children between December 2013-May 2014 and December 2014-May 2015 were enrolled in this study. At least one respiratory virus was found to be positive by RT-PCR in 78 (59%) patients, influenza A (H3N2) was detected in only 8 (6%) patients. In 54 (41%) patients samples no respiratory viral pathogen was detected and in 70 (53%) patients, one non- influenza A virus was detected. The respiratory viral pathogens detected in decreasing rates were:RSV (n = 46, 35%), HCoV (n = 10, 7.5%), adenovirüs (n = 7, 5%), rhinovirüs (n = 6, 4.5%), HMPV (n = 5, 4%), Influenza B (n = 4, 3%) ve human Bocavirus (n = 2, 1.5%). In 10 patients, coinfection was detected, however none was with H3N2. In the H3N2 (+) group, the following risk factors were identified: age older than three years (p < 0.05), asthma history (p < 0.05) and chronic lung diseases (p < 0.05). CONCLUSION: Influenza A virus was detected in 6% of hospitalized patients with influenza-like illness. Viruses other then Influenza, especially RSV, can cause similar symptoms compatible with Influenza-like-illness.