Humans ; Child ; Brain Diseases ; Influenza, Human/diagnosis* ; Influenza A virus

This study aims to develop a rapid and convenient test card for simultaneous detection of influenza A and influenza B viruses using quantum dot-based immunochromatographic assay. The test card consists of a test strip and a plastic casing. The test strip is composed of absorbent paper, a buffer pad, nitrocellulose membrane (NC membrane), sample pad, quantum dot-labeled antibody pad, and polyvinyl chloride (PVC) board. The NC membrane is coated with mouse monoclonal antibodies against influenza A and influenza B viruses for the T lines (test lines), and reference proteins A and B for the C line (control line). The quantum dot-labeled antibody pad contains mouse monoclonal antibody-quantum dot conjugates against influenza A and influenza B viruses. The results showed that the detection limit of the test card for both viruses ranged from 1.51 ×10² to 2.71×10³ TCID50/ml, indicating its sensitivity for accurate detection of influenza A and influenza B viruses without being affected by various variants. The test card exhibited specific reactions with different subtypes of influenza A and influenza B virus culture fluids and showed no cross-reactivity with adenovirus, novel coronavirus, Mycoplasma pneumoniae, respiratory syncytial virus, Staphylococcus aureus, and other pathogens. Overall, the sensitivity and specificity of the test card for simultaneous detection of influenza A and influenza B viruses meet the requirements for clinical use. It offers the advantages of simplicity, rapidity, and no requirement for special equipment, enabling quick auxiliary diagnosis to prevent disease transmission.
Animals ; Mice ; Humans ; Influenza, Human/diagnosis* ; Herpesvirus 1, Cercopithecine ; COVID-19 ; Sensitivity and Specificity ; Influenza B virus

This study aims to develop a rapid and convenient test card for simultaneous detection of influenza A and influenza B viruses using quantum dot-based immunochromatographic assay. The test card consists of a test strip and a plastic casing. The test strip is composed of absorbent paper, a buffer pad, nitrocellulose membrane (NC membrane), sample pad, quantum dot-labeled antibody pad, and polyvinyl chloride (PVC) board. The NC membrane is coated with mouse monoclonal antibodies against influenza A and influenza B viruses for the T lines (test lines), and reference proteins A and B for the C line (control line). The quantum dot-labeled antibody pad contains mouse monoclonal antibody-quantum dot conjugates against influenza A and influenza B viruses. The results showed that the detection limit of the test card for both viruses ranged from 1.51 ×10² to 2.71×10³ TCID50/ml, indicating its sensitivity for accurate detection of influenza A and influenza B viruses without being affected by various variants. The test card exhibited specific reactions with different subtypes of influenza A and influenza B virus culture fluids and showed no cross-reactivity with adenovirus, novel coronavirus, Mycoplasma pneumoniae, respiratory syncytial virus, Staphylococcus aureus, and other pathogens. Overall, the sensitivity and specificity of the test card for simultaneous detection of influenza A and influenza B viruses meet the requirements for clinical use. It offers the advantages of simplicity, rapidity, and no requirement for special equipment, enabling quick auxiliary diagnosis to prevent disease transmission.
Animals ; Mice ; Humans ; Influenza, Human/diagnosis* ; Herpesvirus 1, Cercopithecine ; COVID-19 ; Sensitivity and Specificity ; Influenza B virus

OBJECTIVE: To clarify the clinical characteristics of influenza pneumonia in the elderly patients and the relationship between D-dimer and the severity of influenza pneumonia. METHODS: In the study, 52 hospitalized patients older than 65 years with confirmed influenza pneumonia diagnosed in Peking University People's Hospital on 5 consecutive influenza seasons from 2014 were retrospectively analyzed. General information, clinical symptoms, laboratory data, treatment methods and prognosis of the patients were collected. The relationship between D-dimer and pneumonia severity was analyzed, and receiver operating characteristic (ROC) curve was used to evaluate the predictive value of D-dimer. RESULTS: Among the 52 patients, 31 were male (31/52, 59.6%), the average age was (77.1±7.4) years, and 19 of them (36.5%) were diagnosed with severe pneumonia. About 70% patients presenting with fever. In the severe group, the patients were more likely to complain of dyspnea than in the non-severe group (14/19, 73.7% vs. 10/33, 30.3%, P=0.004), severe pneumonia group had higher level of CURB-65 (confusion, urea, respiratory rate, blood pressure, and age>65), pneumonia severity index (PSI), C-reactive protein, urea nitrogen, lactate dehydrogenase, fasting glucose, and D-dimer (P value was 0.004, < 0.001, < 0.001, 0.003, 0.038, 0.018, and < 0.001, respectively), albumin was lower than that in the non-severe group [(35.8±5.6) g/L vs. (38.9±3.5) g/L, t=-2.348, P=0.018]. There was a significant positive correlation between the D-dimer at the first admission and PSI score (r=0.540, 95%CI: 0.302 to 0.714, P < 0.001), while a significant negative correlation with PaO₂/FiO₂ (r=-0.559, 95%CI: -0.726 to -0.330, P < 0.001). Area under the curve of D-dimer was 0.765 (95%CI: 0.627 to 0.872). Area under the curve of PSI was 0.843 (95%CI: 0.716 to 0.929). There was no statistically significant difference in test efficacy between the two (Z=2.360, P=0.174). D-dimer level over 1 225 μg/L had a positive predict value for influenza pneumonia in hospital death with a sensitivity of 76.92% and a specificity of 74.36%. CONCLUSION Influenza pneumonia in the elderly always has atypical symptoms, dyspnea is a prominent feature in severe cases, D-dimer level is associated with the severity of influenza pneumonia, and greater than 1 200 μg/L has a good predictive value for in-hospital death in the elderly.
Aged ; Aged, 80 and over ; Fibrin Fibrinogen Degradation Products ; Hospital Mortality ; Humans ; Influenza, Human/diagnosis* ; Male ; Pneumonia/diagnosis* ; Prognosis ; ROC Curve ; Retrospective Studies ; Severity of Illness Index

The emergence of coronavirus disease 2019 (COVID-19) not only poses a serious threat to the health of people worldwide but also affects the global economy. The outbreak of COVID-19 began in December 2019, at the same time as the influenza season. However, as the treatments and prognoses of COVID-19 and influenza are different, it is important to accurately differentiate these two different respiratory tract infections on the basis of their respective early-stage characteristics. We reviewed official documents and news released by the National Health Commission of the People's Republic of China, the Chinese Center for Disease Control and Prevention (China CDC), the United States CDC, and the World Health Organization (WHO), and we also searched the PubMed, Web of Science, Excerpta Medica database (Embase), China National Knowledge Infrastructure (CNKI), Wanfang, preprinted bioRxiv and medRxiv databases for documents and guidelines from earliest available date up until October 3rd, 2020. We obtained the latest information about COVID-19 and influenza and summarized and compared their biological characteristics, epidemiology, clinical manifestations, pathological mechanisms, treatments, and prognostic factors. We show that although COVID-19 and influenza are different in many ways, there are numerous similarities; thus, in addition to using nucleic acid-based polymerase chain reaction (PCR) and antibody-based approaches, clinicians and epidemiologists should distinguish between the two using their respective characteristics in early stages. We should utilize experiences from other epidemics to provide additional guidance for the treatment and prevention of COVID-19.
COVID-19/therapy* ; Diagnosis, Differential ; Female ; Humans ; Influenza, Human/therapy* ; Male ; Pandemics/prevention & control* ; Prognosis ; SARS-CoV-2

Monoclonal antibodies (MAbs) are widely applied in disease diagnoses. Herein, we report a MAb, WF-4, against Influenza A virus nucleoprotein (NP), its broad response with Influenza A virus, and its application in an immunohistochemistry (IHC) assay. WF-4 was screened by immunofluorescence assay (IFA). The results showed that its reactivity with baculovirus-expressed full-length recombinant NP (rNP) in Western blot (WB), indicating its IHC applicability. Fifteen Influenza A virus (reference subtypes H1 to H15) infected chicken embryonated chorioallantoic membranes (CAM), fixed by formalin, were all detectable in the WF-4-based IHC assay. Also, the reactivity of the IHC test with NP from experimentally inoculated H6N1 and from all recent outbreaks of H5 subtype avian Influenza A virus (AIV) field cases in Taiwan showed positive results. Our data indicate that CAM, a by-product of Influenza A virus preparation, is helpful for Influenza A virus-specific MAb characterization, and that the WF-4 MAb recognizes conserved and linear epitopes of Influenza A virus NP. Therefore, WF-4 is capable of detecting NP antigens via IHC and may be suitable for developing various tests for diagnosis of Influenza A virus and, especially, AIV infection.
Animals ; Antibodies, Monoclonal ; Blotting, Western ; Chickens ; Chorioallantoic Membrane ; Diagnosis ; Disease Outbreaks ; Epitopes ; Fluorescent Antibody Technique ; Formaldehyde ; Immunohistochemistry ; Influenza A virus ; Influenza in Birds ; Influenza, Human ; Nucleoproteins ; Taiwan

Eosinophilic gastrointestinal disorder (EGID) is an uncommon disease that is accompanied by intestinal eosinophil infiltration without a secondary cause of eosinophilia. Eosinophilic enteritis is a secondary portion of EGID that can present a range of gastrointestinal symptoms according to the affected depth of the intestinal layer. The subserosal type of eosinophilic enteritis presenting as ascites is relatively rarer than the mucosal type. In general, eosinophilic enteritis occurs in patients with food allergies, but its mechanism is unclear. The authors experienced a 29-year-old female patient with a large amount of ascites with diarrhea and abdominal pain. The patient was diagnosed with an influenza A infection one week earlier. Peripheral eosinophilia (absolute eosinophil count: 6,351 cells/mm³) and eosinophilic ascites (97% of white blood cells in the ascites are eosinophil) were present. Abdominal CT revealed a large amount of ascites and edematous changes in the ileum and ascending colon wall. A diagnosis of eosinophilic enteritis was confirmed as eosinophilic ascites by paracentesis, with eosinophil infiltration of the bowel wall by an endoscopic biopsy. The patient's symptoms improved rapidly after using steroids. To the best of the author's knowledge, this is the first report of eosinophilic enteritis with massive ascites after an influenza A virus infection in a Korean adult.
Abdominal Pain ; Adult ; Ascites ; Biopsy ; Colon, Ascending ; Diagnosis ; Diarrhea ; Enteritis ; Eosinophilia ; Eosinophils ; Female ; Food Hypersensitivity ; Humans ; Ileum ; Influenza A virus ; Influenza, Human ; Leukocytes ; Paracentesis ; Steroids ; Tomography, X-Ray Computed

Eosinophilic gastrointestinal disorder (EGID) is an uncommon disease that is accompanied by intestinal eosinophil infiltration without a secondary cause of eosinophilia. Eosinophilic enteritis is a secondary portion of EGID that can present a range of gastrointestinal symptoms according to the affected depth of the intestinal layer. The subserosal type of eosinophilic enteritis presenting as ascites is relatively rarer than the mucosal type. In general, eosinophilic enteritis occurs in patients with food allergies, but its mechanism is unclear. The authors experienced a 29-year-old female patient with a large amount of ascites with diarrhea and abdominal pain. The patient was diagnosed with an influenza A infection one week earlier. Peripheral eosinophilia (absolute eosinophil count: 6,351 cells/mm³) and eosinophilic ascites (97% of white blood cells in the ascites are eosinophil) were present. Abdominal CT revealed a large amount of ascites and edematous changes in the ileum and ascending colon wall. A diagnosis of eosinophilic enteritis was confirmed as eosinophilic ascites by paracentesis, with eosinophil infiltration of the bowel wall by an endoscopic biopsy. The patient's symptoms improved rapidly after using steroids. To the best of the author's knowledge, this is the first report of eosinophilic enteritis with massive ascites after an influenza A virus infection in a Korean adult.
Abdominal Pain ; Adult ; Ascites ; Biopsy ; Colon, Ascending ; Diagnosis ; Diarrhea ; Enteritis ; Eosinophilia ; Eosinophils ; Female ; Food Hypersensitivity ; Humans ; Ileum ; Influenza A virus ; Influenza, Human ; Leukocytes ; Paracentesis ; Steroids ; Tomography, X-Ray Computed

PURPOSE: Enzyme-linked immunosorbent assay (ELISA) has been used in the diverse field to evaluate influenza virus infection; for the surveillance, diagnosis, efficacy evaluation, and development of the vaccine. The aim of this study was to establish an ELISA for detecting HA strain-specific antibodies using recombinant pandemic A H1N1 (pH1N1) HA1 (rHA1) protein. MATERIALS AND METHODS: rHA1 was produced in baculovirus system. The clinical performance of the developed ELISA was validated using human serum samples, by comparison with standard methods for detecting a neutralizing antibody; hemagglutination inhibition (HI) assay and microneutralization test (MNT). The ability of the ELISA system to evaluate the efficacy test of an influenza vaccine was explored by measuring antibody levels in the serum of vaccinated mice. RESULTS: Our ELISA could detect anti-rHA1 antibody in influenza-infected patients and vaccinated subjects. Compared to HI assay and MNT as reference methods, our method showed good performance in detection of anti-rHA1 antibody. Detection of the anti-rHA1 antibody in vaccinated mice and its correlation with titers in HI assay was also proved in a mice model. CONCLUSION: An ELISA system using rHA1 of pH1N1 influenza virus was developed, and showed good clinical performance in diagnosis of influenza virus infection and evaluation of the vaccination efficacy in both human and animal models.
Animals ; Antibodies ; Antibodies, Neutralizing ; Baculoviridae ; Diagnosis ; Enzyme-Linked Immunosorbent Assay* ; Hemagglutination ; Humans ; Influenza A virus ; Influenza Vaccines ; Influenza, Human* ; Methods ; Mice ; Models, Animal ; Orthomyxoviridae* ; Pandemics* ; Vaccination

BACKGROUND/AIMS: Due to advances in diagnostic techniques, clinicians are more frequently performing influenza diagnostic tests and referring to their test results ahead of the administration of neuraminidase inhibitors (NAIs). To investigate the clinical significance of the time from symptom onset to laboratory diagnosis, we reviewed the clinical characteristics of adult patients with influenza who had an early laboratory diagnosis (ED) or a late laboratory diagnosis (LD) at one of four tertiary care centers during a seasonal outbreak of influenza. METHODS: Clinical data were collected from 1,405 adults during the 2013 to 2014 influenza season. A patient was regarded as receiving an ED or LD if he/she received an influenza diagnostic test at 0 to 1 or 4 to 7 days after symptom onset, respectively. Early NAI therapy and late NAI therapy were defined as the administration of NAI ≤ 2 or > 2 days after symptom onset, respectively. RESULTS: Nearly half of the patients (47.0%) received an ED (n = 661), whereas 13.5% (n = 190) received a LD. Patients with a LD had initial symptoms of cough, sputum production, and dyspnea and experienced pneumonia, antibiotic therapy, hospitalization, and admission to the intensive care unit more often than those with an ED. NAI therapy and early NAI therapy were less frequent in patients with a LD than those with an ED. Of the analyzed baseline characteristics, age ≥ 50 years, influenza B infection, and diagnosis using a polymerase chain reaction test were significantly associated with a LD. CONCLUSIONS: LD was associated with inappropriate antiviral therapy and complicated presenting features in adult patients with seasonal influenza. ED of influenza should be emphasized, especially for older adults.
Adult* ; Antiviral Agents ; Clinical Laboratory Techniques ; Cough ; Delayed Diagnosis* ; Diagnosis ; Diagnostic Tests, Routine ; Dyspnea ; Hospitalization ; Humans ; Influenza, Human* ; Intensive Care Units ; Neuraminidase ; Pneumonia ; Polymerase Chain Reaction ; Seasons* ; Sputum ; Tertiary Care Centers