Swine-origin Influenza A (H1N1) Virus Research Articles

Analysis of codon usage preference in hemagglutinin genes of the swine-origin influenza A (H1N1) virus.

The swine-origin influenza A (H1N1) virus (S-OIV) has come to the forefront since 2009 and was identified as a new reassortant strain. The hemagglutinin (HA) glycoprotein mediates virus binding, contains antigenic regions recognized by neutralizing antibodies, and is associated with viral cross-species infection and adaption. The comparison study of codon usage preferences in influenza viral genomes was less extensive. In this study, we used codon usage pattern analyses to validate the adaption and origins of S-OIV. Codon usage pattern was used to estimate the host adaption of S-OIVs. Phylogenetic analysis of the HA gene was conducted to understand the phylogeny of H1N1 viruses isolated from different hosts. Amino acid signature pattern on antigenic sites of HA was analyzed to understand the antigenic characteristics. Results of phylogenetic analyses of HA gene indicate that S-OIVs group in identical clusters. The synonymous codon usage pattern analyses indicate that the effective number of codons versus GC content at the third codon position in the HA1 gene slightly differ from those in swine H1N1 and gradually adapted to human. Our data indicate that S-OIV evolution occurred according to positive selection within these antigenic regions. A comparison of antigenic site amino acids reveals similar signature patterns between S-OIV and 1918 human influenza strains. This study proposes a new and effective way to gain a better understanding of the features of the S-OIV genome and evolutionary processes based on the codon usage pattern. It is useful to trace influenza viral origins and cross-species virus transmission.

The role of initial radiologic and clinical manifestations in predicting the prognosis for pneumonia caused by H1N1 influenza virus.

The aim of this study is to investigate the prognostic values of initial radiologic findings and preexisting medical conditions in pneumonia caused by H1N1 influenza virus that were obtained during the novel swine-origin influenza A (H1N1) virus (S-OIV) pandemic spread. Thirty-nine patients hospitalized due to H1N1 infection between September and December 2009 were retrospectively evaluated regarding the radiologic and clinical aspects. The thoracic computed tomography (CT) findings of all patients were assessed and accompanying conditions that may raise the morbidity were stated. The patients were divided into two groups as those who needed the intensive care unit administration and those treated with brief hospitalization; initial radiologic findings and preexisting medical situations of patients were compared among both groups respectively in terms of their prognostic value. In 39 patients with H1N1 infection (21 males and 18 females; mean age of 53.9±14 in range between 19 and 99 years); the necessity of intensive care was significantly higher in patients with solely chronic obstructive pulmonary disease (COPD) (P=0.008, Odds ratio: 27) or co-existence of COPD and malignity (Odds ratio: 13); however, no statistically significant difference between two groups was observed regarding the radiologic facts or other combinations of accompanying medical conditions in terms of any effects to the prognosis. In the H1N1 (S-OIV) pandemic, we observed that merely the contribution to the diagnostic process; the radiologic features have no significance as being prognostic indicator. Additionally; the superposition of H1N1 infection in patients with either COPD or COPD by malignity was stated to be a potential risk factor in terms of increased morbidity.

Immunophenotype Expressions and Cytokine Profiles of Influenza A H1N1 Virus Infection in Pediatric Patients in 2009

Background. A novel swine-origin influenza A H1N1 virus (S-OIV) caused human infection and acute respiratory illness in 2009, resulting in an influenza pandemic. Objectives. This study characterized the immune responses of S-OIV infection in pediatric patients at risk of pulmonary complications. Methods. All enrolled pediatric patients were confirmed virologically for S-OIV infection in 2009-2010, prospectively. Changes in cellular immunophenotypes were analyzed using flow cytometry. Plasma cytokine levels associated with S-OIV infection by pulmonary and without pulmonary complications were measured using cytokine cytometric bead assay kits. Results. A total of 85 patients with a mean age of 10.3 years were recruited. The level of C-reactive protein (CRP) was high in patients exhibiting pulmonary complications. The percentage of cellular immunophenotypes did not change between patients with and without pulmonary complications. The absolute numbers of peripheral blood mononuclear cells (PBMC), CD3, CD8, and CD16CD56 decreased with acute S-OIV pulmonary complications. Acute influenza infection with pulmonary complications was associated with high plasma concentrations of IL-1β, IL-6, IL-12, and IFN-γ. Conclusion. Immunophenotype studies have reported variability in immune response to the severity of S-OIV infections. Acute phase cytokine profiles of the 2009 S-OIV infection might have contributed to the pathogenesis of the pulmonary complications.

High-resolution computed tomography findings of swine-origin influenza A (H1N1) virus (S-OIV) infection: comparison with scrub typhus

Swine-origin influenza A (H1N1) virus (S-OIV) infection and scrub typhus, also known as tsutsugamushi disease can manifest as acute respiratory illnesses, particularly during the late fall or early winter, with similar radiographic findings, such as a predominance of ground-glass opacity (GGO). To differentiate S-OIV infection from scrub typhus using high-resolution computed tomography (HRCT). We retrospectively reviewed the HRCT findings of 14 patients with S-OIV infection and 10 patients with scrub typhus. We assessed the location, cross-sectional distribution, and the presence of a peribronchovascular distribution of GGO and consolidations on HRCT. We also assessed the presence of interlobular septal thickening, bronchial wall thickening, pneumothorax, pneumomediastinum, pleural effusion, and mediastinal or axillary lymph node enlargement. Scrub typhus was more common than S-OIV in elderly patients (P < 0.001). The monthly incidences of S-OIV and scrub typhus infection reached a peak between October and November. About 86% of S-OIV patients and 80% of scrub typhus patients presented with GGO. About 67% of the GGO lesions in S-OIV had a peribronchovascular distribution, but this was absent in scrub typhus (P = 0.005). Consolidation (93% vs. 10%, P < 0.001) and bronchial wall thickening (43% vs. 0%, P = 0.024) were more frequent in S-OIV infection than scrub typhus. Interlobular septal thickening (90% vs. 36%, P = 0.013) and axillary lymphadenopathy (90% vs. 0%, P < 0.001) were more common in scrub typhus than S-OIV infection. There was considerable overlap in HRCT findings between S-OIV infection and scrub typhus. However, S-OIV showed a distinctive peribronchovascular distribution of GGO lesions. Consolidation and bronchial wall thickening were seen more frequently in S-OIV infection, whereas interlobular septal thickening and axillary lymphadenopathy were more common in scrub typhus. Thus, CT could be helpful for differential diagnosis between S-OIV infection and scrub typhus.

Rapid and Highly Sensitive Method for Influenza A (H1N1) Virus Detection

In this study, we applied the developed paired surface plasma waves biosensor (PSPWB) in a dual-channel biosensor for rapid and sensitive detection of swine-origin influenza A (H1N1) virus (S-OIV). In conjunction with the amplitude ratio of the signal and the reference channel, the stability of the PSPWB system is significantly improved experimentally. The theoretical limit of detection (LOD) of the dual-channel PSPWB for S-OIV is 30 PFU/mL (PFU, plaque-forming unit), which was calculated from the fitting curve of the surface plasmon resonance signal with a S-OIV clinical isolate concentration in phosphate-buffered saline (PBS) over a range of 18-1.8 × 10(6) PFU/mL. The LOD is 2 orders of magnitude more sensitive than the commercial rapid influenza diagnostic test at worst and an order of magnitude less sensitive than real-time quantitative polymerase chain reaction (PCR) whose LOD for S-OIV in PBS was determined to be 3.5 PFU/mL in this experiment. Furthermore, under in vivo conditions, this experiment demonstrates that the assay successfully measured S-OIV at a concentration of 1.8 × 10(2) PFU/mL in mimic solution, which contained PBS-diluted normal human nasal mucosa. Most importantly, the assay time took less than 20 min. From the results, the dual-channel PSPWB potentially offers great opportunity in developing an alternative PCR-free diagnostic method for rapid, sensitive, and accurate detection of viral pathogens with epidemiological relevance in clinical samples by using an appropriate pathogen-specific antibody.

Serial evaluation of high-resolution CT findings in patients with pneumonia in novel swine-origin influenza A (H1N1) virus infection

The purpose of our study was to review the changes in the serial high-resolution CT (HRCT) findings from patients with novel swine-origin influenza A (H1N1) virus (S-OIV) infection. HRCT findings of 70 patients with presumed or laboratory-confirmed novel S-OIV infection were reviewed. The pattern (consolidation, ground glass, fibrosis and air trapping), distribution and extent of abnormality of the lesions on the HRCT were evaluated at different time points. To assess changes that occurred over time, the CT scans in 56 patients were examined in sequence. The most common CT findings in patients with S-OIV infection are ground-glass opacities with or without consolidation at the first week. The abnormalities peaked at the second week and resolved after that time, which resulted in substantial reduced residual disease at 4 weeks or later. The development of fibrosis was noted in the first week and peaked at the third week of illness (34.7%), then decreased slowly after that time. The mean time of air trapping being noted after the onset of symptoms was 55.5 ± 20.6 days. Comparing the findings of initial CT, most results (96.4%) of follow-up chest CT findings showed improvement (p<0.01). The abnormalities of ground-glass opacities and/or consolidation on initial CT scans tended to resolve to fibrosis, which then resolved completely or displayed substantially reduced residual disease. HRCT may show more changes in disease progression and play an important role in the evaluation of severe S-OIV.

H1N1 pneumonia: our experience in 50 patients with a severe clinical course of novel swine-origin influenza A (H1N1) virus (S-OIV).

PurposeThe authors reviewed chest radiographs (CXR) and thin-section computed tomography (CT) findings of pulmonary complications in a selected population of 50 consecutive patients with severe novel swine-origin influenza A (H1N1) virus (S-OIV) pneumonia who were seen at the Subintensive Respiratory Unit (UTSIR) and at the Intensive Care Unit (ICU) at Monaldi Hospital, Naples, Italy.Materials and methodsCXR and CT findings of 50 patients who fulfilled the World Health Organisation (WHO) criteria for S-OIV infection were reviewed by four radiologists. The final study group of 50 patients was divided into two subgroups on the basis of clinical course: group 1 consisted of 42 patients requiring noninvasive mechanical ventilation and admitted to the UTSIR; group 2 consisted of eight patients who required ICU admission and extracorporeal membrane oxygenation or advanced mechanical ventilation from October 2009 to December 2009. All patients underwent CXR and thinsection multidetector CT (MDCT) scan; the initial and follow-up radiographs and CT scans were evaluated for the presentation and follow-up pattern (consolidation, groundglass opacities, nodules, reticulation), distribution and extent of abnormality.ResultsAll patients had radiological signs of pulmonary involvement. Ground-glass opacity and consolidation, which was mainly peripheral, was the most frequent finding. In three patients, we report for the first time in viral pneumonia the reversed halo sign. Lesion extent was related to aggressiveness of the illness. More often, both lungs were involved (82%). Thoracic comorbidity was present in 18% of patients; 22% of patients was obese, and in this group, the clinical course was more aggressive than in the others with the same lesion extent at imaging. Furthermore, superinfection led to worsening of the clinical conditions.ConclusionsThe most common CXR and CT findings in patients with S-OIV infection were unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On MDCT, ground-glass opacities and areas of consolidation had a predominant peribronchovascular and subpleural distribution, resembling organising pneumonia; they progressed to bilateral extensive airspace disease in severely ill patients.

Pneumonia induced by swine-origin influenza A (H1N1) infection: chest computed tomography findings in children.

PurposeThe purpose of this study was to determine the features of chest computed tomography (CT) in children with swine-origin influenza A (H1N1) virus (S-OIV).Materials and methodsThe study population consisted of 16 children with laboratory-confirmed S-OIV infection (12 boys, 4 girls), with an age range of 5–10 years (mean 6.3 years). Pneumonia was suspected in these patients based on clinical features or confirmed by radiography. All subjects underwent CT for close evaluation of pneumonia, including characteristics, distribution, extent, and other findings such as pleural effusion, pneumothorax, and pneumomediastinum.ResultsThe predominant CT finding was consolidation plus ground-grass opacity (GGO) (11/16, 69%). The consolidation-dominant pattern was found in 10 of 16 (66%) patients, and 1 (6%) was GGO-dominant. One (6%) had only GGO. In all, 7 of the 16 patients had segmental or lobar consolidation. Abnormal opacities were primarily distributed in the central lung zone (8/16, 50%) and were multifocal (15/16, 94%). Four showed atelectasis (4/16, 25%). Pneumomediastinum was observed in 4 of 16 (25%). One patient had negative radiographic findings but was positive on CT.ConclusionMultifocal consolidation with central distribution is a common CT finding in children with S-OIV, but there are few GGO-dominant cases. Widespread consolidation (segmental or lobar) is also common.

ChemInform Abstract: Origins and Evolutionary Genomics of the Novel Swine‐Origin Influenza A (H1N1) Virus in Humans — Past and Present Perspectives

AbstractReview: 68 refs.

Novel Swine-origin Influenza a (H1N1) Virus Infection of the Lung Presenting With a "Crazy-paving" Pattern on High-resolution CT

A novel swine-origin influenza A (H1N1) virus (S-OIV) infection has nonspecific clinical presentations and imaging findings, usually displaying pulmonary involvement. We report a 37-year-old man with S-OIV pneumonia and unusual high-resolution computed tomography (HRCT) findings. He passed away 7 days after hospitalization. The unusual HRCT findings showed a crazy-paving pattern of both lungs. We suggest the inclusion of S-OIV pneumonia in the differential diagnosis of patients with crazy-paving pattern on HRCT, and this imaging pattern may be an indication of severe illness status.

Origins and Evolutionary Genomics of the Novel Swine-Origin Influenza A (H1N1) Virus in Humans —Past and Present Perspectives

Swine influenza viruses cause annual epidemics and occasional pandemics claiming the lives of millions from the early history up to the present days. This virus has drawn on a bag of evolutionary tricks to survive in one or another form in both humans and pigs with novel gene constellations through the periodic importation or exportation of viral genes. A prime example is emergence of pandemic novel swine-origin influenza A (H1N1) virus (S-OIV) in 2009 that have transmitted to and spread among humans, resulting in outbreaks internationally. The phylogenetic analysis of sequences of all genes of the S-OIV, showed that its genome contained six gene segments that were similar to ones previously found in triple-reassortant swine influenza viruses circulating in pigs in North America. The genes encoding neuraminidase and M protein were most closely related to those in influenza A viruses circulating in swine populations in Eurasia. This unique genetic combination of influenza virus gene segments leading to the emergence of novel S-OIV that had not been seen before in the world. Here, it has been used evolutionary analysis to estimate the timescale of the origins and the early development of the S-OIV epidemic. This paper shows that it was derived from several viruses circulating in swine and makes a briefly review over the origins and evolutionary genomics of current S-OIV in humans with historical perspectives with a view to exhibition of evolutionary relationship between past and present origins of swine influenza viruses.

Development and Evaluation of Reverse Transcription Loop-Mediated Isothermal Amplification Assay for Rapid and Real-Time Detection of the Swine-Origin Influenza A H1N1 Virus

The recent emergence of the swine-origin influenza A H1N1 virus (S-OIV) poses a serious global health threat. Rapid detection and differentiation of S-OIV from seasonal influenza is crucial for patient management and control of the epidemics. A one-step, single-tube accelerated and quantitative S-OIV-specific H1 reverse transcription loop-mediated isothermal amplification (RTLAMP) assay for clinical diagnosis of S-OIV by targeting the H1 gene is reported in this article. A comparative evaluation of the H1-specific RTLAMP assay vis-à-vis the World Health Organization-approved real-time polymerase chain reaction (RTPCR), involving 239 acute-phase throat swab samples, demonstrated exceptionally higher sensitivity by picking up all of the 116 H1N1-positive cases and 36 additional positive cases among the negatives that were sequence-confirmed as S-OIV H1N1. None of the real-time RTPCR-positive samples were missed by the RTLAMP system. The comparative analysis revealed that S-OIV RTLAMP was up to tenfold more sensitive than the World Health Organization real-time RTPCR; it had a detection limit of 0.1 tissue culture infectious dosage of 50/ml. One of the most attractive features of this isothermal gene amplification assay is that it seems to have an advantage in monitoring gene amplification by means of SYBR Green I dye-mediated naked-eye visualization within 30 minutes compared to 2 to 3 hours for a real-time reverse transcription polymerase chain reaction. This suggests that the RTLAMP assay is a valuable tool for rapid, real-time detection and quantification of S-OIV in acute-phase throat swab samples without requiring sophisticated equipment.

Envelope Proteins Pertain with Evolution and Adaptive Mechanism of the Novel Influenza A/H1N1 in Humans

The novel swine-origin influenza A/H1N1 virus (S-OIV) first detected in April 2009 has been identified to transmit from human to human directly and is the cause of currently emerged pandemic. In this study, nucleotide and deduced amino acid sequences of hemagglutinin (HA) and neuraminidase (NA) of the S-OIV and other influenza A viruses were analyzed through bioinformatic tools for phylogenetic analysis, genetic recombination and point mutation to investigate the emergence and adaptation of the S-OIV in human. The phylogenetic analysis showed that the HA comes from triple reassortant influenza A/H1N2 and the NA from Eurasian swine influenza A/H1N1 indicating HA and NA to descend from different lineages during the genesis of the S-OIV. Recombination analysis nullified the possibility of occurrence of recombination in HA and NA denoting the role of reassortment in the outbreak. Several conservative mutations are observed in the amino acid sequences of the HA and NA and this mutated residues are identical in the S-OIV. The results reported herein suggested the notion that the recent pandemic is the result of reassortment of different genes from different lineages of two envelope proteins, HA and NA which are responsible for antigenic activity of virus. This study further suggests that the adaptive capability of the S-OIV in human is acquired by the unique mutations generated during emergence.

Detection of swine-origin influenza A (H1N1) viruses using a localized surface plasmon coupled fluorescence fiber-optic biosensor

Swine-origin influenza A (H1N1) virus (S-OIV) was identified as a new reassortant strain of influenza A virus in April 2009 and led to an influenza pandemic. Accurate and timely diagnoses are crucial for the control of influenza disease. We developed a localized surface plasmon coupled fluorescence fiber-optic biosensor (LSPCF-FOB) which combines a sandwich immunoassay with the LSP technique using antibodies against the hemagglutinin (HA) proteins of S-OIVs. The detection limit of the LSPCF-FOB for recombinant S-OIV H1 protein detection was estimated at 13.9 pg/mL, which is 10 3-fold better than that of conventional capture ELISA when using the same capture antibodies. For clinical S-OIV isolates measurement, meanwhile, the detection limit of the LSPCF-FOB platform was calculated to be 8.25 × 10 4 copies/mL, compared with 2.06 × 10 6 copies/mL using conventional capture ELISA. Furthermore, in comparison with the influenza A/B rapid test, the detection limit of the LSPCF-FOB for S-OIV was almost 50-fold in PBS solution and 25-fold lower in mimic solution, which used nasal mucosa from healthy donors as the diluent. The findings of this study therefore indicate that the high detection sensitivity and specificity of the LSPCF-FOB make it a potentially effective diagnostic tool for clinical S-OIV infection and this technique has the potential to be applied to the development of other clinical microbe detection platforms.

Perception, attitudes and knowledge regarding the 2009 swine‐origin influenza A (H1N1) virus pandemic among health‐care workers in Australia

To determine the perceptions, attitudes and knowledge of Australian health-care workers (HCWs) regarding the novel, swine-origin influenza A (H1N1) virus (S-OIV) outbreak that reached the country in early May 2009. Self-administered, anonymous Web-based survey conducted during the early stages of the S-OIV pandemic. Participants comprised hospital- and community-based medical and nursing staff, medical students, allied health professionals, laboratory staff and administrative personnel. Of the 947 participants surveyed, 59.4% were not convinced that Australia was sufficiently prepared for an influenza pandemic. Only 17.6% of the participants stated they were prepared to work unconditionally during a pandemic; 36.5% stated they would work if they had access to antiviral treatment; 27.9% would if provided with antiviral prophylaxis; and 7.5% would refuse to work. In addition, 37.5% of the participants responded they would refuse or avoid being involved in screening suspected cases. A total of 47.7% admitted to possessing a personal supply of antivirals or having considered this option. Only 48.0% provided a realistic estimate of the mortality associated with an influenza pandemic at a population level. HCWs overestimating the mortality risk and HCWs believing the efficacy of antiviral prophylaxis to be low were significantly less likely to be prepared to work (P= 0.04 and P= 0.0004, respectively). To ensure adequate staffing during an influenza pandemic, preparedness plans should anticipate significant levels of absenteeism by choice. Interventions aimed at increasing staff retention during a pandemic require further evaluation.

Fatal 2009 pandemic influenza A (H1N1) in a bone marrow transplant recipient

Conditions characterized by immunosuppression have been recently reported as risk factors for severe novel swine-origin influenza A (H1N1) virus (S-OIV) infection during the current 2009 pandemic. We report clinical and virological findings, antiviral therapy, and post-mortem study of S-OIV in an adult bone marrow transplant recipient. The viral genome was amplified by real time reverse transcriptase polymerase chain reaction (RT-PCR) from a nasopharyngeal swab specimen. The patient developed acute respiratory distress syndrome, septic shock, and eventually succumbed with a severe pulmonary haemorrhage. To the best of our knowledge, the entire clinical/therapy management and pathological examination in a transplant recipient infected with the S-OIV has not been previously documented. The fatal ending in this bone marrow transplant recipient supports recommendations that call for education measures, S-OIV vaccination, early diagnosis and aggressive treatment in the transplant population.

Pneumonia in novel swine-origin influenza A (H1N1) virus infection: High-resolution CT findings

Objective The purpose of our study was to review the initial high-resolution CT (HRCT) findings in pneumonia patients with presumed/laboratory-confirmed novel swine-origin influenza A (H1N1) virus (S-OIV) infection and detect pneumonia earlier. Materials and methods High-resolution CT (HRCT) findings of 106 patients with presumed/laboratory-confirmed novel S-OIV (H1N1) infection were reviewed. The 106 patients were divided into two groups according to the serious condition of the diseases. The pattern (consolidation, ground-glass, nodules, and reticulation), distribution, and extent of abnormality on the HRCT were evaluated in both groups. The dates of the onset of symptoms of the patients were recorded. Results The predominant CT findings in the patients at presentation were unilateral or bilateral multifocal asymmetric ground-glass opacities alone ( n = 29, 27.4%), with unilateral or bilateral consolidation ( n = 50, 47.2%). The consolidation had peribronchovascular and subpleural predominance. The areas of consolidation were found mainly in the posterior, middle and lower regions of the lungs. Reticular opacities were found in 6 cases of the initial MDCT scan. The extent of disease was greater in group 1 patients requiring advanced mechanical ventilation, with diffuse involvement in 19 patients (63.3%) of group 1 patients, and only 15/76 (19.7%) of group 2 patients ( p < 0.01, χ 2 test). 20 cases (19%) of the 106 patients had small bilateral or unilateral pleural effusions. None had evidence of hilar or mediastinal lymph node enlargement on CT performed at admission or later. Conclusions The most common radiographic and CT findings in patients with S-OIV infection are unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On HRCT, the ground-glass opacities had a predominant peribronchovascular and subpleural distribution. CT plays an important role in the early recognition of severe S-OIV (H1N1).

Radiological findings of pneumonia in patients with swine-origin influenza A virus (H1N1)

PurposeDuring spring 2009, a pandemic swine-origin influenza A (H1N1) virus (S-OIV) emerged and spread globally. We describe the chest X-ray and computed tomography (CT) findings of 40 patients with pneumonia due to S-OIV observed in our institution.Material and methodsAmong 534 patients with S-OIV, according to the US Centers for Disease Control and Prevention case definition, seen between June and November 2009, 121 underwent chest X-ray and 40 (median age 44 years, range 16–79) had pneumonia. The initial chest radiographs were evaluated for pattern, distribution and extent of lung abnormalities. Unenhanced chest CT scans were performed in two patients and were reviewed for the same findings. Underlying medical conditions were present in 42% of patients (17/40).ResultsOur patients had predominantly mild illness, and pneumonia was observed in 40 individuals (40/121 patients who had chest X-rays, 33%; and 40/534 patients with S-OIV, 7.5%). However, S-OIV can cause severe illness requiring admission to the intensive care unit for advanced mechanical ventilation and extracorporeal life support, including adult respiratory distress syndrome (ARDS) and death. The major radiological abnormalities observed were interstitial changes (60.0%), with (22.0%) or without patchy ground-glass appearance, mostly bilateral, and located in the lower lung zones (7.5%). Extensive disease was seen in 37.5% (15/40), and ARDS was observed in three individuals (0.30%)with underlying medical conditions. Subtle pleural effusion was noted in four patients.ConclusionsIn our series, the most frequent pneumonia patterns observed during S-OIV (H1N1) virus were interstitial changes and patchy ground-glass appearance, mostly bilateral, and located in the lower lung zones. CT, performed in severely ill patients, confirmed the ARDS identified with chest X-rays, better depicting the features and extent of lung abnormalities.

Prise en charge dans un service d’urgence de l’épidémie à virus pandémique A(H1N1) 2009 à Saint-Pierre, île de La Réunion. Juillet–Août 2009

The 2009 pandemic influenza A (H1N1) virus has emerged to cause the first pandemic of the 21st century. On July 3, 2009, novel swine-origin influenza A (H1N1) virus (S-OIV) was identified in Reunion Island, French overseas department located in the southern hemisphere. The present study describes the characteristics and the impact of the epidemic on the activity of an emergency department (ED) from July 3 to August 31, 2009. Patients consulting the ED with a discharge diagnosis of influenza-like illness were analyzed. The ED activity in 2009, compared to 2008, increased by 0.5% in July and 9.7% in August. In July and August, respectively 7.1 and 20.0% cases of S-OIV infection were hospitalized. For the 394 patients studied (186 males, 36.2+/-18.5 years), 199 (50.5%) were reported to have comorbidity or risk factor (RF) for complications. Complications occurred in 112 patients (28.4%). The most common complications were bronchospasme (52.7%), pneumonia (32.1%), decompensation caused by comorbidity (17.9%). Seventy-three patients (18.5%) required hospitalization. Patients aged 65 and over accounted for 10.9% of all patients, 31.5% of hospitalized patients and 21.4% of complicated S-OIV infection. Regardless of age, comorbidity and / or RF was reported in 80.2% of complicated S-OIV infection and 86.3% of hospitalized patients. The circuit of patients with S-OIV infection was initially focused on "consultation S-OIV" localized in ED. This organization mobilized several health professionals, disorganized the various medical departments involved, and was unsuitable for the childcare or patient's monitoring with signs of poor tolerance. This organization, even identifying S-OIV patients at their arrival, referred patients to different areas of the hospital and various consultation rooms in ED. Recommendations for surveillance, prevention and policy for persons with RF, particularly respiratory disease, are justified. This feedback can raise questions about the patient's circulation in hospital and adjust plans for the organization.

CT Utilization in the Prospective Diagnosis of a Case of Swine-Origin Influenza A (H1N1) Viral Infection

The purpose of this paper is to demonstrate the potential role of CT in the early diagnosis of swine-origin influenza A (H1N1) virus (S-OIV) pneumonia. We present a case of acute influenza-like illness in which the CT findings of peribronchovascular and subpleural ground-glass opacities and consolidation resembled organizing pneumonia, and lead the radiologist to prospectively and correctly suggest the diagnosis of S-OIV infection.