Clinical Findings in 111 Cases of Influenza A (H7N9) Virus Infection

The authors' affiliations are listed in the Appendix.
New England Journal of Medicine (Impact Factor: 55.87). 05/2013; 368(24). DOI: 10.1056/NEJMoa1305584
Source: PubMed


During the spring of 2013, a novel avian-origin influenza A (H7N9) virus emerged and spread among humans in China. Data were lacking on the clinical characteristics of the infections caused by this virus.

Using medical charts, we collected data on 111 patients with laboratory-confirmed avian-origin influenza A (H7N9) infection through May 10, 2013.

Of the 111 patients we studied, 76.6% were admitted to an intensive care unit (ICU), and 27.0% died. The median age was 61 years, and 42.3% were 65 years of age or older; 31.5% were female. A total of 61.3% of the patients had at least one underlying medical condition. Fever and cough were the most common presenting symptoms. On admission, 108 patients (97.3%) had findings consistent with pneumonia. Bilateral ground-glass opacities and consolidation were the typical radiologic findings. Lymphocytopenia was observed in 88.3% of patients, and thrombocytopenia in 73.0%. Treatment with antiviral drugs was initiated in 108 patients (97.3%) at a median of 7 days after the onset of illness. The median times from the onset of illness and from the initiation of antiviral therapy to a negative viral test result on real-time reverse-transcriptase-polymerase-chain-reaction assay were 11 days (interquartile range, 9 to 16) and 6 days (interquartile range, 4 to 7), respectively. Multivariate analysis revealed that the presence of a coexisting medical condition was the only independent risk factor for the acute respiratory distress syndrome (ARDS) (odds ratio, 3.42; 95% confidence interval, 1.21 to 9.70; P=0.02).

During the evaluation period, the novel H7N9 virus caused severe illness, including pneumonia and ARDS, with high rates of ICU admission and death. (Funded by the National Natural Science Foundation of China and others.).


Available from: Bin Cao
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    • "Extensive therapeutic interventions including antiviral treatment, oxygen therapy, mechanical ventilation, antibiotics, glucocorticoids, intravenous immunoglobulins, extracorporeal membrane oxygenation, continuous renal replacement therapy, and artificial liver support system therapy were employed. Despite these interventions, a high mortality rate among H7N9-infected patients was observed [2, 3]. Several differences between H7N9-and H5N1-infected patients have been reported, including significantly different patterns of leukopenia and thrombocytopenia and elevated levels of alanine aminotransferase, creatinine kinase, C-reactive protein, and lactate dehydrogenase . "
    [Show abstract] [Hide abstract] ABSTRACT: Background: A novel avian-origin influenza A (H7N9) virus emerged and spread among humans in Eastern China in 2013. Prophylactic treatment with antibiotics and probiotics for secondary infection is as important as antiviral treatment. This study aims to assess the ability of probiotic treatment to restore internal homeostasis under antibiotic pressure and to reduce/ameliorate the risk of secondary infections resulting from infection with the H7N9 virus. Methods: This is a retrospective study in archival samples. Between April 1 and May 10, 2013, 113 stool, sputum, and blood specimens were collected and analyzed by denaturing gradient gel electrophoresis (DGGE) to determine the composition of the patient microbiomes. Microbial diversity was calculated using Gel-Pro analyzer and Past software. Cluster analysis of DGGE pattern profiles was employed to create a phylogenetic tree for each patient, and multidimensional scaling (MDS) and principal component analysis (PCA) were performed to visualize relationships between individual lanes. Results: Five patients had secondary infections, including Klebsiella pneumonia, Acinetobacter baumanii and Candida albicans infection. The DGGE profiles of fecal samples obtained at different time points from the same individual were clearly different, particularly for patients with secondary infections. Shannon's diversity index and evenness index were lower in all infected groups compared to the control group. After B. subtilis and E. faecium or C. butyricum administration, the fecal bacterial profiles of patients who had not been treated with antibiotics displayed a trend of increasing diversity and evenness. C. butyricum failed to reduce/ameliorate secondary infection in H7N9-infected patients, but administration of B. subtilis and E. faecium appeared to reduce/ameliorate secondary infection in one patient. Conclusion: H7N9 infection might decrease intestinal microbial diversity and species richness in humans. C. butyricum failed to reduce/ameliorate secondary infection in H7N9-infected patients. B. subtilis and E. faecium may also play a role in reducing/ameliorating secondary infection in these patients.
    Full-text · Article · Mar 2016 · PLoS ONE
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    • "The most common complications noted were ARDS, respiratory failure, refractory hypoxemia, encephalopathy, rhabdomyolysis, multiorgan dysfunction syndrome, secondary bacterial infections, and septic shock which could lead to death (Peng et al., 2013; Shi et al., 2013a,b; To et al., 2013; WHO, 2013). Other than that, clinical investigation found that lymphocytopenia and thrombocytopenia were prognostic indicators of ARDS and death, while most of the infected H7N9 patients died because of refractory hypoxemia (Gao et al., 2013a). The level of C-reactive protein is also used as a clinical marker for illness severity of human H7N9 infections (Shi et al., 2013a). "
    [Show abstract] [Hide abstract] ABSTRACT: The novel avian influenza A H7N9 virus which caused the first human infection in Shanghai, China; was reported on the 31st of March 2013 before spreading rapidly to other Chinese provinces and municipal cities. This is the first time the low pathogenic avian influenza A virus has caused human infections and deaths; with cases of severe respiratory disease with pneumonia being reported. There were 440 confirmed cases with 122 fatalities by 16 May 2014; with a fatality risk of ∼28%.The median age of patients was 61 years with a male-to-female ratio of 2.4:1. The main source of infection was identified as exposure to poultry and there is so far no definitive evidence of sustained person-to-person transmission. The neuraminidase inhibitors, namely oseltamivir, zanamivir, and peramivir; have shown good efficacy in the management of the novel H7N9 virus. Treatment is recommended for all hospitalized patients, and for confirmed and probable outpatient cases; and should ideally be initiated within 48 h of the onset of illness for the best outcome. Phylogenetic analysis found that the novel H7N9 virus is avian in origin and evolved from multiple reassortments of at least four origins. Indeed the novel H7N9 virus acquired human adaptation via mutations in its eight RNA gene segments. Enhanced surveillance and effective global control are essential to prevent pandemic outbreaks of the novel H7N9 virus.
    Full-text · Article · Mar 2015 · Frontiers in Microbiology
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    • "The imaging findings of H7N9 subtype infection of avian influenza virus resemble to those of H5N1 subtype infection of avian influenza virus, both of which have pulmonary segment or lobar exudative lesions as the predominant imaging findings except that multifocal consolidations have a predilection at lower lobes in cases of H5N1 subtype infection of avian influenza virus [11]. However, differential diagnosis relies on virus isolation and detection [6]. This study has several limitations. "
    [Show abstract] [Hide abstract] ABSTRACT: Objective: To investigate the chest imaging features in H7N9 subtype human avian influenza. Methods: The clinical and imaging data of 7 patients with H7N9 subtype avian influenza were collected and the chest imaging manifestations were analyzed. Results: The main clinical symptoms of H7N9 patients were fever (n = 7) and cough (n = 4). The ground-glass opacities or consolidations in pulmonary segmental or lobar distribution were showed (n = 5) at the initial stage (within 3 days). Air bronchogram could be found in 4 cases. The bilateral lungs were rapidly involved with multiple or diffuse distribution (n = 7) at the progressive stage (3-6 days), and 4 patients were died at this stage. The linear, reticular and honeycomb shadows were seen with partial absorption of lesions (n = 2). Conclusion: The main imaging features of H7N9 subtype human avian influenza are the segmental or lobar consolidations on the initial stage and rapid involvement of bilateral lungs with disease progression.
    Full-text · Article · Feb 2015
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