Epidemiology of seasonal influenza in the Middle East and North Africa regions, 2010-2016: Circulating influenza A and B viruses and spatial timing of epidemics.

BACKGROUND: There is a limited knowledge regarding the epidemiology of influenza in Middle East and North Africa. OBJECTIVES: We described the patterns of influenza circulation and the timing of seasonal epidemics in countries of Middle East and North Africa. METHODS: We used virological surveillance data for 2010-2016 from the WHO FluNet database. In each country, we calculated the median proportion of cases that were caused by each virus type and subtype; determined the timing and amplitude of the primary and secondary peaks; and used linear regression models to test for spatial trends in the timing of epidemics. RESULTS: We included 70 532 influenza cases from seventeen countries. Influenza A and B accounted for a median 76.5% and 23.5% of cases in a season and were the dominant type in 86.8% and 13.2% of seasons. The proportion of influenza A cases that were subtyped was 85.9%, while only 4.4% of influenza B cases were characterized. For most countries, influenza seasonality was similar to the Northern Hemisphere, with a single large peak between January and March; exceptions were the countries in the Arabian Peninsula and Jordan, all of which showed clear secondary peaks, and some countries had an earlier primary peak (in November-December in Bahrain and Qatar). The direction of the timing of influenza activity was east to west and south to north in 2012-2013 and 2015-2016, and west to east in 2014-2015. CONCLUSIONS: The epidemiology of influenza is generally uniform in countries of Middle East and North Africa, with influenza B playing an important role in the seasonal disease burden.

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.

Epidemiology of Hospital Admissions with Influenza during the 2013/2014 Northern Hemisphere Influenza Season: Results from the Global Influenza Hospital Surveillance Network.

BACKGROUND: The Global Influenza Hospital Surveillance Network was established in 2012 to obtain valid epidemiologic data on hospital admissions with influenza-like illness. Here we describe the epidemiology of admissions with influenza within the Northern Hemisphere sites during the 2013/2014 influenza season, identify risk factors for severe outcomes and complications, and assess the impact of different influenza viruses on clinically relevant outcomes in at-risk populations. METHODS: Eligible consecutive admissions were screened for inclusion at 19 hospitals in Russia, Turkey, China, and Spain using a prospective, active surveillance approach. Patients that fulfilled a common case definition were enrolled and epidemiological data were collected. Risk factors for hospitalization with laboratory-confirmed influenza were identified by multivariable logistic regression. FINDINGS: 5303 of 9507 consecutive admissions were included in the analysis. Of these, 1086 were influenza positive (534 A(H3N2), 362 A(H1N1), 130 B/Yamagata lineage, 3 B/Victoria lineage, 40 untyped A, and 18 untyped B). The risk of hospitalization with influenza (adjusted odds ratio [95% confidence interval]) was elevated for patients with cardiovascular disease (1.63 [1.33-2.02]), asthma (2.25 [1.67-3.03]), immunosuppression (2.25 [1.23-4.11]), renal disease (2.11 [1.48-3.01]), liver disease (1.94 [1.18-3.19], autoimmune disease (2.97 [1.58-5.59]), and pregnancy (3.84 [2.48-5.94]). Patients without comorbidities accounted for 60% of admissions with influenza. The need for intensive care or in-hospital death was not significantly different between patients with or without influenza. Influenza vaccination was associated with a lower risk of confirmed influenza (adjusted odds ratio = 0.61 [0.48-0.77]). CONCLUSIONS: Influenza infection was detected among hospital admissions with and without known risk factors. Pregnancy and underlying comorbidity increased the risk of detecting influenza virus in patients hospitalized with influenza-like illness. Our results support influenza vaccination as a measure for reducing the risk of influenza-associated hospital admission.

Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

INTRODUCTION: Determining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes. METHODS: This was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics. RESULTS: 212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics. DISCUSSION: Our findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.

Striking Similarities in the Presentation and Duration of Illness of Influenza A and B in the Community: A Study Based on Sentinel Surveillance Networks in France and Turkey, 2010-2012.

Influenza B represents a high proportion of influenza cases in some seasons (even over 50%). The Influenza B study in General Practice (IBGP) is a multicenter study providing information about the clinical, demographic and socio-economic characteristics of patients affected by lab-confirmed influenza A or B. Influenza B patients and age-matched influenza A patients were recruited within the sentinel surveillance networks of France and Turkey in 2010-11 and 2011-12 seasons. Data were collected for each patient at the swab test day, after 9±2 days and, if not recovered, after 28±5 days. It was related to patient's characteristics, symptoms at presentation, vaccination status, prescriptions of antibiotics and antivirals, duration of illness, follow-up consultations in general practice or emergency room. We performed descriptive analyses and developed a multiple regression model to investigate the effect of patients and disease characteristics on the duration of illness. Overall, 774 influenza cases were included in the study: 419 influenza B cases (209 in France and 210 in Turkey) and 355 influenza A cases (205 in France and 150 in Turkey). There were no differences between influenza A and B patients in terms of clinical presentation and number of consultations with a practitioner; however, the use of antivirals was higher among influenza B patients in both countries. The average (median) reported duration of illness in the age groups 0-14 years, 15-64 years and 65+ years was 7.4 (6), 8.7 (8) and 10.5 (9) days in France, and 6.3 (6), 8.2 (7) and 9.2 (6) days in Turkey; it increased with age but did not differ by virus type; increased duration of illness was associated with antibiotics prescription. In conclusion, our findings show that influenza B infection appears not to be milder disease than influenza A infection.

Epidemiological and virological characteristics of influenza B: results of the Global Influenza B Study.

INTRODUCTION: Literature on influenza focuses on influenza A, despite influenza B having a large public health impact. The Global Influenza B Study aims to collect information on global epidemiology and burden of disease of influenza B since 2000. METHODS: Twenty-six countries in the Southern (n = 5) and Northern (n = 7) hemispheres and intertropical belt (n = 14) provided virological and epidemiological data. We calculated the proportion of influenza cases due to type B and Victoria and Yamagata lineages in each country and season; tested the correlation between proportion of influenza B and maximum weekly influenza-like illness (ILI) rate during the same season; determined the frequency of vaccine mismatches; and described the age distribution of cases by virus type. RESULTS: The database included 935 673 influenza cases (2000-2013). Overall median proportion of influenza B was 22·6%, with no statistically significant differences across seasons. During seasons where influenza B was dominant or co-circulated (>20% of total detections), Victoria and Yamagata lineages predominated during 64% and 36% of seasons, respectively, and a vaccine mismatch was observed in ≈25% of seasons. Proportion of influenza B was inversely correlated with maximum ILI rate in the same season in the Northern and (with borderline significance) Southern hemispheres. Patients infected with influenza B were usually younger (5-17 years) than patients infected with influenza A. CONCLUSION: Influenza B is a common disease with some epidemiological differences from influenza A. This should be considered when optimizing control/prevention strategies in different regions and reducing the global burden of disease due to influenza.

The Global Influenza Hospital Surveillance Network (GIHSN): a new platform to describe the epidemiology of severe influenza.

BACKGROUND: Influenza is a global public health problem. However, severe influenza only recently has been addressed in routine surveillance. OBJECTIVES: The Global Influenza Hospital Surveillance Network (GIHSN) was established to study the epidemiology of severe influenza in consecutive seasons in different countries. Our objective is to describe the GIHSN approach and methods. METHODS: The GIHSN uses prospective active surveillance to identify consecutive influenza admissions in permanent residents of well-defined geographic areas in sites around the world. A core common protocol is followed. After consent, data are collected on patient characteristics and clinical outcomes, respiratory swabs are obtained, and the presence of influenza virus and subtype or lineage is ascertained by polymerase chain reaction. Data are collated and analyzed at the GIHSN coordination center. RESULTS: The GIHSN has run its activities for two consecutive influenza seasons, 2012-2013 and 2013-2014, and hospitals in Brazil, China, France, Russian Federation, Turkey, and Spain have been involved in one or both seasons. Consistency on the application of the protocol and heterogeneity for the first season have been addressed in two previous publications. During both seasons, 19 677 eligible admissions were recorded; 11 843 (60%) were included and tested, and 2713 (23%) were positive for influenza: 991 (37%) A(H1N1); 807 (30%) A(H3N2); 583 (21%) B/Yamagata; 56 (2%) B/Victoria and 151 (6%) influenza A; and 125 (5%) influenza B were not characterized. CONCLUSIONS: The GIHSN is a platform that provides information on severe influenza worldwide, applying a common core protocol and a consistent case definition.

Atypical presentation of human bocavirus: Severe respiratory tract infection complicated with encephalopathy.

Human bocavirus (HBOV) has been reported as a worldwide distributed respiratory pathogen. It has also been associated with encephalitis recently by detection of the virus in cerebrospinal fluid (CSF) of patients presented with encephalitis. This retrospective study aimed to present clinical features of HBOV infections in children with respiratory symptoms and describe unexplained encephalopathy in a subgroup of these patients. Results of 1,143 pediatric nasal samples from mid-December 2013 to July 2014 were reviewed for detection of HBOV. A multiplex real time polymerase chain reaction assay was used for viral detection. Medical records of the patients were retrospectively analyzed. HBOV was detected in 30 patients (2.6%). Median age was 14 months (5-80). Clinical diagnoses were upper respiratory tract infection (n = 10), bronchopneumonia (n = 9), acute bronchiolitis (n = 5), pneumonia (n = 4), acute bronchitis (n = 1), and asthma execarbation (n = 1). Hospitalization was required in 16 (53.3%) patients and 10 (62.5%) of them admitted to pediatric intensive care unit (PICU). Noninvasive mechanical ventilation modalities was applied to four patients and mechanical ventilation to four patients. Intractable seizures developed in four patients while mechanically ventilated on the 2nd-3rd days of PICU admission. No specific reason for encephalopathy was found after a thorough investigation. No mortality was observed, but two patients were discharged with neurological sequela. HBOV may lead to respiratory infections in a wide spectrum of severity. This report indicates its potential to cause severe respiratory infections requiring PICU admission and highlights possible clinical association of HBOV and encephalopathy, which developed during severe respiratory infection.

The role of activated cytotoxic T cells in etiopathogenesis of periodontal disease: does it harm or does it heal?

The objective of this study was to determine the phenotypic profile of blood mononuclear cells, specifically CD8(+)/CD28(+) cells, in patients with generalized aggressive periodontitis (GAgP) and chronic periodontitis (CP) in peripheral blood and in blood obtained from periodontal defect site which might contribute to tissue damage. 13 GAgP, 11 chronic periodontitis (CP) and 5 healthy controls (H) were included in the study. Plaque index (PI), bleeding on probing (BoP), periodontal probing depth (PPD) and clinical attachment level (CAL) were recorded. Blood from the base of periodontal defect site and peripheral blood from the antecubital vein were obtained. Relative counts of CD45(+), CD3(+), CD4(+), CD8(+)/CD28(+), CD8(+)/CD28(-), CD19(+), CD16(+)/CD56(+)/CD3, CD3(+)/CD16(+)/CD56(+) receptors were determined with two color flow cytometry using monoclonal antibodies. BoP, PPD and CAL were significantly higher in both periodontitis groups than healthy controls (p <0.05). Activated cytotoxic T cells, CD8(+)/CD28(+) cells, were significantly elevated in GAgP and CP groups compared to HC both in blood obtained from defect site and blood obtained from systemic circulation (p <0.05). GAgP and CP patients have an increased levels of activated cytotoxic T cells as a result of inflammation which may cause severe tissue damage that lead to severe and rapid loss of periodontal tissues.

First-year results of the Global Influenza Hospital Surveillance Network: 2012-2013 Northern hemisphere influenza season.

BACKGROUND: The Global Influenza Hospital Surveillance Network (GIHSN) was developed to improve understanding of severe influenza infection, as represented by hospitalized cases. The GIHSN is composed of coordinating sites, mainly affiliated with health authorities, each of which supervises and compiles data from one to seven hospitals. This report describes the distribution of influenza viruses A(H1N1), A(H3N2), B/Victoria, and B/Yamagata resulting in hospitalization during 2012-2013, the network's first year. METHODS: In 2012-2013, the GIHSN included 21 hospitals (five in Spain, five in France, four in the Russian Federation, and seven in Turkey). All hospitals used a reference protocol and core questionnaire to collect data, and data were consolidated at five coordinating sites. Influenza infection was confirmed by reverse-transcription polymerase chain reaction. Hospitalized patients admitted within 7 days of onset of influenza-like illness were included in the analysis. RESULTS: Of 5034 patients included with polymerase chain reaction results, 1545 (30.7%) were positive for influenza. Influenza A(H1N1), A(H3N2), and both B lineages co-circulated, although distributions varied greatly between coordinating sites and over time. All age groups were affected. A(H1N1) was the most common influenza strain isolated among hospitalized adults 18-64 years of age at four of five coordinating sites, whereas A(H3N2) and B viruses were isolated more often than A(H1N1) in adults ≥65 years of age at all five coordinating sites. A total of 16 deaths and 20 intensive care unit admissions were recorded among patients with influenza. CONCLUSIONS: Influenza strains resulting in hospitalization varied greatly between coordinating sites and over time. These first-year results of the GIHSN are relevant, useful, and timely. Due to its broad regional representativeness and sustainable framework, this growing network should contribute substantially to understanding the epidemiology of influenza, particularly for more severe disease.

2012-2013 Seasonal influenza vaccine effectiveness against influenza hospitalizations: results from the global influenza hospital surveillance network.

BACKGROUND: The effectiveness of currently licensed vaccines against influenza has not been clearly established, especially among individuals at increased risk for complications from influenza. We used a test-negative approach to estimate influenza vaccine effectiveness (IVE) against hospitalization with laboratory-confirmed influenza based on data collected from the Global Influenza Hospital Surveillance Network (GIHSN). METHODS AND FINDINGS: This was a multi-center, prospective, active surveillance, hospital-based epidemiological study during the 2012-2013 influenza season. Data were collected from hospitals participating in the GIHSN, including five in Spain, five in France, and four in the Russian Federation. Influenza was confirmed by reverse transcription-polymerase chain reaction. IVE against hospitalization for laboratory-confirmed influenza was estimated for adult patients targeted for vaccination and who were swabbed within 7 days of symptom onset. The overall adjusted IVE was 33% (95% confidence interval [CI], 11% to 49%). Point estimates of IVE were 23% (95% CI, -26% to 53%) for influenza A(H1N1)pdm09, 30% (95% CI, -37% to 64%) for influenza A(H3N2), and 43% (95% CI, 17% to 60%) for influenza B/Yamagata. IVE estimates were similar in subjects <65 and ≥65 years of age (35% [95% CI, -15% to 63%] vs.31% [95% CI, 4% to 51%]). Heterogeneity in site-specific IVE estimates was high (I2 = 63.4%) for A(H1N1)pdm09 in patients ≥65 years of age. IVE estimates for influenza B/Yamagata were homogenous (I2 = 0.0%). CONCLUSIONS: These results, which were based on data collected from the GIHSN during the 2012-2013 influenza season, showed that influenza vaccines provided low to moderate protection against hospital admission with laboratory-confirmed influenza in adults targeted for influenza vaccination. In this population, IVE estimates against A(H1N1)pdm09 were sensitive to age group and study site. Influenza vaccination was moderately effective in preventing admissions with influenza B/Yamagata for all sites and age groups.

Predictors of fatality in pandemic influenza A (H1N1) virus infection among adults.

BACKGROUND: The fatality attributed to pandemic influenza A H1N1 was not clear in the literature. We described the predictors for fatality related to pandemic influenza A H1N1 infection among hospitalized adult patients. METHODS: This is a multicenter study performed during the pandemic influenza A H1N1 [A(H1N1)pdm09] outbreak which occurred in 2009 and 2010. Analysis was performed among laboratory confirmed patients. Multivariate analysis was performed for the predictors of fatality. RESULTS: In the second wave of the pandemic, 848 adult patients were hospitalized because of suspected influenza, 45 out of 848 (5.3%) died, with 75% of fatalities occurring within the first 2 weeks of hospitalization. Among the 241 laboratory confirmed A(H1N1)pdm09 patients, the case fatality rate was 9%. In a multivariate logistic regression model that was performed for the fatalities within 14 days after admission, early use of neuraminidase inhibitors was found to be protective (Odds ratio: 0.17, confidence interval: 0.03-0.77, p=0.022), nosocomial infections (OR: 5.7, CI: 1.84-18, p=0.013), presence of malignant disease (OR: 3.8, CI: 0.66-22.01, p=0.133) significantly increased the likelihood of fatality. CONCLUSIONS: Early detection of the infection, allowing opportunity for the early use of neuraminidase inhibitors, was found to be important for prevention of fatality. Nosocomial bacterial infections and underlying malignant diseases increased the rate of fatality.

Viral etiology of influenza-like illnesses during the influenza season between December 2011 and April 2012.

The aim of this study was to determine the frequency of respiratory viruses responsible for respiratory tract infections in Turkish children during the 2011-2012 influenza season. Nasal swabs were obtained from patients with symptoms suggestive of an influenza-like illness between December 2011 and April 2012. Samples were analyzed with multiplex real-time polymerase chain reaction (RT-PCR) to help identify the causative viral pathogen. A total of 200 patients were enrolled in the study. A respiratory virus was detected successfully in 102 (51%) children; influenza A (H3N2) in 39.2%, influenza B in 23.5%, RSV in 15.6%, rhinovirus in 13.7%, bocavirus in 2.9%, coronavirus in 2.9%, and metapneumovirus in 0.9% of patients. Only one patient was co-infected with bocavirus and influenza A virus. A statistically significant difference in the mean age of presentation was observed between the various viral pathogens (P < 0.001). Patients with RSV were significantly younger whereas children infected with the influenza viruses were significantly older. Comparison of symptoms revealed that fever and headache occurred more frequently with the influenza viruses than the other viruses combined (P < 0.001, <0.05). Durations of symptoms such as fever, cough, nasal congestion, and rhinorrhea were also significantly longer in the influenza group (P < 0.001, <0.005, <0.001, <0.005, respectively). Demographic analyses revealed that the school/daycare attendance was the only parameter associated with a significantly increased risk for influenza infection. With an overall viral pathogen detection rate of 51%, findings of the present study suggest other respiratory pathogens, whether viral or bacterial, may also lead to hospital visits due to influenza-like illnesses in children.

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 vaccination in Turkey: prevalence of risk groups, current vaccination status, factors influencing vaccine uptake and steps taken to increase vaccination rate.

Influenza infections cause considerable morbidity and mortality not only during the pandemics but also during annual epidemics. Vaccines are the most effective tools for preventing the infection. Although World Health Organization (WHO) and Ministry of Health (MoH) recommends vaccination for people at increased risk, sales data indicate that vaccination rate remains low in Turkey. Vaccine recommended groups are well defined and reimbursed in Turkey. However, the prevalence of people in risk groups, current vaccination rates and factors influencing vaccine uptake which are essential in order to develop and sustain effective strategies to increase vaccination rate are not documented. A thorough literature review was performed to determine the estimated number of people in risk groups, vaccination rates, factors influencing vaccine uptake in Turkey. Actions taken by the health authorities in order to increase the vaccine uptake among specified risk groups are also summarized. Based on the published prevalence rates, current study calculated that there are approximately 27 to 33 million people in risk groups. In addition, there are 428,000 health care providers serving in the public sector who are at increased risk for influenza infections. The lowest reported vaccination rate (5.9%) was in the elderly ≥65 years of age and the highest (27.3%) in patients with COPD. Finally, survey results indicated that leading factor negatively influencing vaccine uptake was disbelief in the effectiveness of vaccine. In order to increase vaccination coverage, vaccines are provided to health care providers free of charge and reimbursed for those in the risk groups. Realizing the fact that combating flu requires multidisciplinary collaboration, a stakeholder network, Grip Platformu, has been established in 2011 with the endorsement of the MoH to increase influenza awareness and vaccine coverage rates among risk groups in accordance with WHO recommendations.

[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.

Influenza B-associated encephalopathy in two adults.

Influenza virus is associated with a variety of neurological complications, of which the most commonly encountered are seizures and encephalopathy. Acute encephalitis and postinfectious encephalopathy have been reported infrequently in association with influenza A and B virus infections. We describe two previously healthy adults who presented with encephalopathy with a virologically documented influenza B infection.

Effectiveness of a new bioequivalent formulation of oseltamivir (Enfluvir®) on 2010-2011 seasonal influenza viruses: an open phase IV study.

OBJECTIVE: The aim of this multicenter prospective study was to evaluate the efficacy of a new bioequivalent formulation of oseltamivir for the treatment of influenza A, influenza B, and H1N1 during the 2010-2011 influenza season. METHODS: We compared the symptoms and signs of 300 pediatric patients presenting to three university hospitals with an influenza-like illness between January and March 2011. Nasal swab specimens were collected from all children and tested by reverse-transcription polymerase chain reaction (RT-PCR) for influenza viruses. After randomization, half of the participants were prescribed oseltamivir, while the other half were observed conservatively. Forty patients who were followed-up for influenza prior to the study were also included in the evaluation. RESULTS: Influenza was confirmed by RT-PCR in 129 children, 71 of whom were prescribed oseltamivir. The durations of the symptoms fever, cough, nasal congestion, and rhinorrhea were significantly shorter for patients who were treated with oseltamivir compared with untreated patients (p<0.002 for all symptoms). Early initiation of oseltamivir therapy (within 48 h of the onset of symptoms) was associated with more favorable outcomes and an earlier recovery than in patients for whom treatment was delayed (beyond 48 h). Thirty-seven patients (28.7%) had H1N1, 44 (34.1%) had influenza A, 46 (35.7%) had influenza B, one (0.8%) had H1N1 plus influenza A, and one (0.8%) had influenza A plus influenza B viruses. In the comparison of the duration of symptoms according to the different virus types, a statistically significant difference was only observed in patients with influenza B who had a longer duration of cough (p<0.001), nasal congestion (p<0.001), and rhinorrhea (p<0.001). CONCLUSIONS: Oseltamivir is an effective treatment for the management of seasonal influenza and H1N1, and should be initiated immediately without waiting for laboratory confirmation of diagnosis.

Clinical and epidemiological characteristics of pandemic influenza A/(H1N1) in hospitalized pediatric patients at a university hospital, Istanbul, Turkey.

BACKGROUND: The aim of this study was to describe the clinical and epidemiological characteristics of pandemic influenza in hospitalized children. METHODS: A total of 114 patients with suspected H1N1 virus infection were hospitalized, and nasal swabs were sent to National Influenza Reference Laboratory for confirmation of pandemic influenza A (H1N1) virus infection by rRT-PCR assay. RESULTS: Forty-six female and 68 male patients were included in the study. Age of the patients ranged from 40 days to 16 years. Clinical and/or radiological pneumonia were detected in 96% of all. Sixteen patients required mechanical ventilation due to hypoxemia. Previously healthy children required mechanical ventilation and oxygen therapy more than patients with chronic diseases. Elevated levels of CRP and LDH in patients with respiratory distress and patients who required mechanical ventilation were statistically significant. CONCLUSION: Our study showed that progress of pandemic influenza infection in previously healthy children is as severe as their counterparts with chronic underlying diseases.

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.