Permanent Complete Heart Block: A Rare Complication of Influenza Infection

The cardiovascular complications of viral illnesses are often underestimated in clinical practice. The influenza virus, one of the most prevalent viral infections, has been associated with a wide spectrum of arrhythmias that are typically transient and self-resolving. We present the case of a 60-year-old female with no prior cardiac comorbidities who developed a complete heart block after an influenza infection. She presented to the clinic with flu-like symptoms and was found to have a complete heart block with a junctional escape rhythm. Polymerase chain reaction testing subsequently confirmed an influenza A infection. She was initially placed on a temporary pacemaker. However, a permanent dual-chamber pacemaker was implanted as bradycardia persisted. Later follow-ups in the cardiology clinic showed that the patient remained dependent on the pacemaker. While there are a few descriptions of influenza-induced transient atrioventricular block, cases of influenza-induced permanent complete heart block are extremely rare, particularly in the absence of severe myocardial inflammation.

Machine-learning-algorithms-based diagnostic model for influenza A in children

BACKGROUND

At present, nucleic acid testing is the gold standard for diagnosing influenza A, however, this method is expensive, time-consuming, and unsuitable for promotion and use in grassroots hospitals. This study aimed to establish a diagnostic model that could accurately, quickly, and simply distinguish between influenza A and influenza like diseases.

METHODS

Patients with influenza-like symptoms were recruited between December 2019 and August 2023 at the Children's Hospital Affiliated to Shandong University and basic information, nasopharyngeal swab and blood routine test data were included. Computer algorithms including random forest, GBDT, XGBoost and logistic regression (LR) were used to create the diagnostic model, and their performance was evaluated using the validation data sets.

RESULTS

A total of 4188 children with influenza-like symptoms were enrolled, of which 1992 were nucleic acid test positive and 2196 were matched negative. The diagnostic models based on the random forest, GBDT, XGBoost and logistic regression algorithms had AUC values of 0.835,0.872,0.867 and 0.784, respectively. The top 5 important features were lymphocyte (LYM) count, age, serum amyloid A (SAA), white blood cells (WBC) count and platelet-to-lymphocyte ratio (PLR). GBDT model had the best performance, the sensitivity and specificity were 77.23% and 80.29%, respectively.

CONCLUSIONS

A computer algorithm diagnosis model of influenza A in children based on blood routine test data was established, which could identify children with influenza A more accurately in the early stage, and was easy to popularize.

Exploiting Substrate Specificities of 6-O-Sulfotransferases to Enzymatically Synthesize Keratan Sulfate Oligosaccharides

Keratan sulfate (KS) is a glycosaminoglycan that is widely expressed in the extracellular matrix of various tissue types, where it is involved in many biological processes. Herein, we describe a chemo-enzymatic approach to preparing well-defined KS oligosaccharides by exploiting the known and newly discovered substrate specificities of relevant sulfotransferases. The premise of the approach is that recombinant GlcNAc-6-O-sulfotransferases (CHST2) only sulfate terminal GlcNAc moieties to give GlcNAc6S that can be galactosylated by B4GalT4. Furthermore, CHST1 can modify the internal galactosides of a poly-LacNAc chain; however, it was found that a GlcNAc6S residue greatly increases the reactivity of CHST1 of a neighboring and internal galactoside. The presence of a 2,3-linked sialoside further modulates the site of modification by CHST1, and a galactoside flanked by 2,3-Neu5Ac and GlcNAc6S is preferentially sulfated over the other Gal residues. The substrate specificities of CHST1 and 2 were exploited to prepare a panel of KS oligosaccharides, including selectively sulfated N-glycans. The compounds and several other reference derivatives were used to construct a microarray that was probed for binding by several plant lectins, Siglec proteins, and hemagglutinins of influenza viruses. It was found that not only the sulfation pattern but also the presentation of epitopes as part of an O- or N-glycan determines binding properties.

Thiazolide Prodrug Esters and Derived Peptides: Synthesis and Activity

Amino acid ester prodrugs of the thiazolides, introduced to improve the pharmacokinetic parameters of the parent drugs, proved to be stable as their salts but were unstable at pH > 5. Although some of the instability was due to simple hydrolysis, we have found that the main end products of the degradation were peptides formed by rearrangement. These peptides were stable solids: they maintained significant antiviral activity, and in general, they showed improved pharmacokinetics (better solubility and reduced clearance) compared to the parent thiazolides. We describe the preparation and evaluation of these peptides.

More than a Tripledemic: Influenza A Virus, Respiratory Syncytial Virus, SARS-CoV-2, and Human Metapneumovirus in Wastewater during Winter 2022-2023

Wastewater monitoring can provide insights into respiratory disease occurrence in communities that contribute to the wastewater system. Using daily measurements of RNA of influenza A (IAV), respiratory syncytial virus (RSV), and human metapneumovirus (HMPV), as well as SARS-CoV-2 in wastewater solids from eight publicly owned treatment works in the Greater San Francisco Bay Area of California between July 2022 and early July 2023, we identify a "tripledemic" when concentrations of IAV, RSV, and SARS-CoV-2 peaked at approximately the same time. HMPV was also widely circulating. We designed novel hydrolysis probe RT-PCR assays for different IAV subtype markers to discern that the dominant circulating IAV subtype was H3N2. We show that wastewater data can be used to identify the onset and offset of wastewater disease occurrence events. This information can provide insight into disease epidemiology and timely, localized information to inform hospital staffing and clinical decision making to respond to circulating viruses. Whereas RSV and IAV wastewater events were mostly regionally coherent, HMPV events displayed localized occurrence patterns.

The Rare Presentation of Spontaneous Pneumothorax in a Pediatric Patient

Children presenting to the Emergency Department (ED) with upper respiratory infection (URI) symptoms of unresolved cough are not uncommon. Differentiation of the child's symptoms with thorough history and physical and when appropriate, further evaluation with blood work and imaging is the responsibility of the ED physician. In a clinical environment with increasing ED visits due to nonspecific URIs in children, it is also important not to overutilize an emergent workup with unnecessary testing. Our case involves a patient with atypical symptoms and hopes to highlight the importance of keeping a broad differential for all patients upon initial evaluation. Spontaneous pneumothorax is a potentially life-threatening condition. Our five-year-old patient presented with an unresolved cough being treated by an outpatient physician. He had no prior airway disease diagnosis. Severe cough in the absence of prior airway disease is notably less likely, but not an unseen cause of spontaneous pneumothorax. Our patient, however, developed just that. He was officially diagnosed with a right-sided pneumothorax on chest x-ray, underwent supplemental oxygen therapy, and was ultimately transferred to a pediatric hospital for continuation of care. Once there, our patient gradually improved was diagnosed as an asthmatic, and was started on appropriate maintenance medications. It is important to remain vigilant when examining multiple pediatric patients in a shift and to keep in mind that even otherwise healthy pediatric patients are at risk for spontaneous pneumothorax.  Spontaneous pneumothorax is a potentially life-threatening condition. Our five-year-old patient had no prior airway disease diagnosis making spontaneous pneumothorax notably less likely, however, from severe cough our patient developed just that. He was officially diagnosed with right-sided pneumothorax, underwent supplemental oxygen therapy, and was transferred to a pediatric hospital. Once there patient gradually improved, he was diagnosed as an asthmatic and started on appropriate medication to keep his breathing stable. It is essential to keep in mind that even otherwise pediatric patients are at risk for spontaneous pneumothoraxes and we as emergency physicians must keep this in mind during our evaluation.

Editorial: Global Surveillance of Highly Pathogenic Avian Influenza Viruses in Poultry, Wild Birds, and Mammals to Prevent a Human Influenza Pandemic

Strains of avian influenza A, believed to have originated in poultry with transmission to wild birds, have been associated with epidemics and four major pandemics in humans in the past century. The 1918 influenza pandemic was caused by an avian strain of the influenza A(H1N1) virus that initially adapted to infect humans and then rapidly spread between humans. Since 2021, highly pathogenic avian influenza (HPAI) virus subtypes have been identified in poultry and wild birds. In October 2022, the HPAI virus variant A(H5N1) was isolated from intensively farmed American mink. The World Health Organization (WHO), the US Centers for Disease Control and Prevention (CDC), and the European Union Reference Laboratory for Avian Influenza (EURL) have stated that the risk of human infection from birds and mammals and human-to-human transmission from known HPAI viruses is currently low. However, they recommend increased infection surveillance and preparedness. This editorial aims to present the status of HPAI virus transmission in poultry, wild birds, and mammals to highlight the importance of international infection surveillance, control, and preparedness to prevent the next human influenza pandemic.

A fatal case of COVID-19-associated meningoencephalitis in a patient coinfected with influenza A

We report a case of COVID-19-associated meningoencephalitis with a fatal outcome in a male patient with concomitant influenza A, who had been hospitalized at the beginning of 2022, in the Northeastern region of Brazil. He died due to cardiopulmonary arrest after developing status epilepticus on the third day of hospitalization. The SARS-CoV-2 RNA was detected in cerebrospinal fluid and Influenza A was detected in the nasopharyngeal swab. Meningoencephalitis due to COVID-19 is a rare manifestation and physicians must be aware of this complication, mainly during the pandemic. In viral co-circulation situations, the possibility of respiratory coinfections should be remembered.

Virulence network of interacting domains of influenza a and mouse proteins

There exist several databases that provide virus-host protein interactions. While most provide curated records of interacting virus-host protein pairs, information on the strain-specific virulence factors or protein domains involved, is lacking. Some databases offer incomplete coverage of influenza strains because of the need to sift through vast amounts of literature (including those of major viruses including HIV and Dengue, besides others). None have offered complete, strain specific protein-protein interaction records for the influenza A group of viruses. In this paper, we present a comprehensive network of predicted domain-domain interaction(s) (DDI) between influenza A virus (IAV) and mouse host proteins, that will allow the systematic study of disease factors by taking the virulence information (lethal dose) into account. From a previously published dataset of lethal dose studies of IAV infection in mice, we constructed an interacting domain network of mouse and viral protein domains as nodes with weighted edges. The edges were scored with the Domain Interaction Statistical Potential (DISPOT) to indicate putative DDI. The virulence network can be easily navigated via a web browser, with the associated virulence information (LD₅₀ values) prominently displayed. The network will aid influenza A disease modeling by providing strain-specific virulence levels with interacting protein domains. It can possibly contribute to computational methods for uncovering influenza infection mechanisms mediated through protein domain interactions between viral and host proteins. It is available at https://iav-ppi.onrender.com/home.

Human placental hematopoietic stem cell derived natural killer cells (CYNK-001) mediate protection against influenza a viral infection

Influenza A virus (IAV) infections are associated with a high healthcare burden around the world and there is an urgent need to develop more effective therapies. Natural killer (NK) cells have been shown to play a pivotal role in reducing IAV-induced pulmonary infections in preclinical models; however, little is known about the therapeutic potential of adoptively transferred NK cells for IAV infections. Here, we investigated the effects of CYNK-001, human placental hematopoietic stem cell derived NK cells that exhibited strong cytolytic activity against a range of malignant cells and expressed high levels of activating receptors, against IAV infections. In a severe IAV-induced acute lung injury model, mice treated with CYNK-001 showed a milder body weight loss and clinical symptoms, which led to a delayed onset of mortality, thus demonstrating their antiviral protection in vivo. Analysis of bronchoalveolar lavage fluid (BALF) revealed that CYNK-001 reduced proinflammatory cytokines and chemokines highlighting CYNK-001’s anti-inflammatory actions in viral induced-lung injury. Furthermore, CYNK-001-treated mice had altered immune responses to IAV with reduced number of neutrophils in BALF yet increased number of CD8+ T cells in the BALF and lung compared to vehicle-treated mice. Our results demonstrate that CYNK-001 displays protective functions against IAV via its anti-inflammatory and immunomodulating activities, which leads to alleviation of disease burden and progression in a severe IAV-infected mice model. The potential of adoptive NK therapy for IAV infections warrants clinical investigation.

Influenza-Like Illness Among Personnel Responding to U.S. Quarantine of Cruise Ship Passengers Exposed to SARS-CoV-2

OBJECTIVES

Before community transmission of COVID-19 was recognized in the United States, cruise ship passengers with high risk for exposure to SARS-CoV-2 were repatriated and quarantined. We describe cases of influenza-like illness (ILI) among responders.

METHODS

We reviewed situation reports and responder illness reports to characterize ill responders, including illness onset date, symptoms, fever, diagnostic tests, potential breaches in PPE use, and return to work status.

RESULTS

Among 339 responders, nine (3%) reported ILI. No breaches in PPE were reported. Three responders with ILI were tested for both SARS-CoV-2 infection and influenza A; none tested positive for SARS-CoV-2 infection and two tested positive for influenza A.

CONCLUSIONS

Despite an outbreak of ILI among responders, none were diagnosed with COVID-19, suggesting preventive measures in place might have been sufficient to prevent responders from SARS-CoV-2 exposure.

Matrix Protein 2 Extracellular Domain-Specific Monoclonal Antibodies Are an Effective and Potentially Universal Treatment for Influenza A

Influenza virus infection causes significant morbidity and mortality worldwide. Humans fail to make a universally protective memory immune response to influenza A. Hemagglutinin and Neuraminidase undergo antigenic drift and shift, resulting in new influenza A strains to which humans are naive. Seasonal vaccines are often ineffective and escape mutants have been reported to all treatments for influenza A. In the absence of a universal influenza A vaccine or treatment, influenza A will remain a significant threat to human health. The extracellular domain of the M2-ion channel (M2e) is an ideal antigenic target for a universal therapeutic agent, as it is highly conserved across influenza A serotypes, has a low mutation rate, and is essential for viral entry and replication. Previous M2e-specific monoclonal antibodies (M2e-MAbs) show protective potential against influenza A, however, they are either strain specific or have limited efficacy. We generated seven murine M2e-MAbs and utilized in vitro and in vivo assays to validate the specificity of our novel M2e-MAbs and to explore the universality of their protective potential. Our data shows our M2e-MAbs bind to M2e peptide, HEK cells expressing the M2 channel, as well as, influenza virions and MDCK-ATL cells infected with influenza viruses of multiple serotypes. Our antibodies significantly protect highly influenza A virus susceptible BALB/c mice from lethal challenge with H1N1 A/PR/8/34, pH1N1 A/CA/07/2009, H5N1 A/Vietnam/1203/2004, and H7N9 A/Anhui/1/2013 by improving survival rates and weight loss. Based on these results, at least four of our seven M2e-MAbs show strong potential as universal influenza A treatments.IMPORTANCE Despite a seasonal vaccine and multiple therapeutic treatments, Influenza A remains a significant threat to human health. The biggest obstacle is producing a vaccine or treatment for influenza A is their universality or efficacy against not only seasonal variances in the influenza virus, but also against all human, avian, and swine serotypes and, therefore, potential pandemic strains. M2e has huge potential as a target for a vaccine or treatment against influenza A. It is the most conserved external protein on the virus. Antibodies against M2e have made it to clinical trials, but not succeeded. Here, we describe novel M2e antibodies produced in mice that are not only protective at low doses, but that we extensively test to determine their universality and found to be cross protective against all strains tested. Additionally, our work begins to elucidate the critical role of isotype for an influenza A monoclonal antibody therapeutic.

Economic and health impacts of infectious diseases in China: A protocol for systematic review and meta analysis

BACKGROUND

A worldwide concern has been raised that novel infectious diseases may outbreak rapidly with a limited response time due to globalization. Severe Acute Respiratory Syndrome, influenza A, Avian Influenza Virus, and Corona Virus Disease 2019 are acute respiratory diseases that have been affected by the movements of people, and globalization accelerates these movements. These infectious diseases not only have an overwhelming health impact but also impact the worldwide economy.

METHODS

We will conduct a systematic review and meta-analysis in Chinese National Knowledge Infrastructure, WANFANG Database, and the VIP Database for Chinese Technical Periodicals, Web of Science, PubMed, EMBASE, the Cochrane Library, EBSCO host, ProQuest, ProQuest Dissertations & Theses A&I, SAGE Journals, ScienceDirect, JSTOR, and Scopus. We will evaluate the risk of bias of included RCTs according to the criteria and technique proposed in the Cochrane Handbook V.5.1.0 and use ROBINS-I to assess risk of bias in nonrandomized studies. We will use GRADE to evaluate the quality of evidence.

RESULTS

Results of this review will be submitted to a peer-reviewed journal.

CONCLUSION

To the best of our knowledge, this study will firstly evaluate both health and economic impact of infectious diseases in china and may provide strategy development ideas for future resistance.

Aspergillus and Rhizopus Fungal Coinfection in a Patient With Multiple Myeloma

Opportunistic fungal infections are rare but life-threatening in immunocompromised patients. We discuss a case of an immunocompromised patient with multiple myeloma who presented with shortness of breath, fever, ocular palsy, and hemiplegia. She was found to have influenza A respiratory tract infection complicated by invasive aspergillosis and mucormycosis. Investigation revealed invasive fungal sinusitis and cerebritis. Serum biomarkers, beta-d-glucan, and galactomannan failed to detect fungal disease. We believe that our case is unique as there is limited data available regarding the occurrence of invasive fungal infections after Influenza infections. Furthermore, it highlights the hurdles in the diagnosis of disseminated fungal infection.

Influenza A with hemorrhagic shock and encephalopathy syndrome in an adult: A case report

INTRODUCTION

Hemorrhagic shock and encephalopathy syndrome (HSES) is a type of acute encephalopathy mainly seen in infants. It is a syndrome encompassing an onset of high fever, disturbance of consciousness, convulsion, and shock that rapidly progresses to watery diarrhea and liver and renal dysfunctions. It is extremely rare in adults, and the number of reports is limited worldwide. We report the case of an adult patient with HSES, which occurred after influenza A infection.

PATIENT CONCERNS

A 52-year-old man visited his family doctor 2 days after he noticed fever and was diagnosed with influenza A using an influenza rapid diagnosis kit; he underwent treatment on an outpatient basis. He was immediately hospitalized after developing fever, abdominal pain, malaise, and shock 16 hours after the commencement of the treatment. Abrupt acute brain swelling was noted 24 hours after hospitalization.

DIAGNOSES

The antibody titer to influenza A (H3N2) was 1:40. Computed tomography obtained 24 hours after treatment initiation confirmed acute cerebral edema and cerebral herniation. Electroencephalogram at that time showed a flat line.

INTERVENTIONS

For the treatment of influenza A, laninamivir 150 mg was started immediately after the diagnosis by the family doctor, and 600 mg dose was given daily after hospitalization (or since 24 hours after the treatment initiation). For the management of shock, dobutamine 3 μg/kg/min and noradrenaline up to 0.2 μg/kg/min were used together with bolus infusion.

OUTCOMES

The patient was declared brain dead on his 6th hospital day and he died on his 27th hospital day.

CONCLUSION

Drastic courses such as that in our case with HSES can follow influenza infections even in adults.

Influenza-Associated Acute Necrotizing Encephalopathy in Siblings

Encephalopathy is an important complication associated with influenza, most frequently observed in young children, with a wide range of severity. The most severe category of influenza-associated encephalopathy (IAE) is acute necrotizing encephalopathy (ANE), characterized by high frequency of neurologic sequelae and fatal outcomes. We report two young siblings who developed fever and seizures with altered mental status. Influenza A(H1N1)pdm09 virus infection was identified in upper respiratory tract specimens from both patients, and neuroimaging revealed bilateral inflammatory lesions, consistent with acute necrotizing encephalopathy. Neither child had received influenza vaccination. Both children progressed to critical illness and required invasive mechanical ventilation. In addition to critical care management, both patients received high-dose corticosteroids, mannitol, anticonvulsants, and antiviral treatment of influenza. The older child recovered fully and was discharged 2 weeks after illness onset, but the younger sibling developed severe brainstem edema and cerebellar tonsillar herniation, and died on illness day 11. Both children tested positive for Ran Binding Protein 2 (RANBP2) gene mutations. RANBP2 is a genetic polymorphism associated with recurrent episodes of necrotizing encephalitis with respiratory viral infections. Annual influenza vaccination is especially important for ANE survivors, with or without RANBP2 mutations, their household contacts, and caregivers. During influenza season, close monitoring of any child with a history of neurological complications associated with respiratory illness is indicated, with prompt initiation of antiviral treatment with onset of acute respiratory illness, and influenza testing performed by molecular assay.

Secondary Bacterial Pneumonia by Staphylococcus aureus Following Influenza A Infection Is SaeR/S Dependent

Staphylococcus aureus is a predominant cause of fatal pneumonia following influenza A virus (IAV) infection. Herein we investigate the influence of antecedent IAV infection on S. aureus virulence gene expression. Using a murine model, comparing the USA300 and USA300ΔsaeR/S strains, we demonstrate that S. aureus pathogenesis following IAV infection is SaeR/S dependent. Furthermore, we show that IAV modulates the lung environment to rapidly up-regulate S. aureus virulence factors containing the SaeR-binding domain. Data demonstrate that the pathogen response to IAV infection impacts host outcome and provides evidence that the ability of S. aureus to sense and respond to the lung environment determines severity of pneumonia.

Rhabdomyolysis Associated with Influenza A Virus Infection

Influenza A associated with rhabdomyolysis has become more commonly recognized in recent years. It requires prompt recognition and treatment in order to prevent heme pigment-induced acute kidney injury. Here we report a 50-year-old female without a significant past medical history who presented with a one-week history of fevers, chills, fatigue, and generalized body aches. She was on no prior medication. Laboratory studies were significant for leukocytosis and elevated creatinine kinase up to a peak of 28,216 IU/L. Rapid influenza antigen testing was positive for influenza A virus. The patient was diagnosed with influenza A-induced rhabdomyolysis. According to our literature review, we are the first to report a case of influenza A-induced rhabdomyolysis in the 2017-2018 flu season. This case highlights the importance of considering rhabdomyolysis as a manifestation of an influenza infection.

Swine Flu: Knowledge, Attitude, and Practices Survey of Medical and Dental Students of Karachi

Introduction

Pakistan is extremely susceptible to an influenza outbreak, as it shares borders with the most affected countries, namely China and India. The medical and dental students come into direct contact with the affected population and should be aware of the risk factors and signs and symptoms pertaining to swine influenza virus (SIV). Hence, this survey was conducted to assess the knowledge, perceptions and self-care practices of the medical and dental students with regards to this pandemic.

Methods

A descriptive, cross-sectional study was conducted to evaluate the swine flu-related knowledge, attitudes and practices of the medical and dental students at various institutions in Karachi, Pakistan. We approached 613 students that were available on the dates of this survey, keeping a medical to dental student ratio of 75:25. All students from first to final year comprised of the study population, and no internists or medical personnel were included. The questionnaire was divided into three sections, namely knowledge, attitudes and, practices. All questions were based on a multiple choice format. The data were entered and interpreted using the IBM Statistical Package for the Social Sciences 23.0 (IBM Corp., Armonk, New York).

Results

The majority of the students were aware that the swine flu is a transmittable disease (n=485, 80.8%). Most students identified the signs and symptoms correctly; however, diarrhea (15.5%) and vomiting (32.2%) were the least correct answers (n=93, n=193 respectively). Most of the preventative measures were reported accurately by the participants. Despite this, only 15.5% students (n=93) reported the use of a facemask when suffering from fever, cough and a runny nose.

Conclusion

There is a dire need for the routine integration of the awareness and management programs in the medical and dental schools. There exists a gap between the policy and practice, and it is high time we bridge the divide. The students should also be vaccinated annually for influenza A.

[Clinical value of fluorescence lateral flow immunoassay in diagnosis of influenza A in children]

OBJECTIVE

To evaluate the clinical value of a new type of fluorescence lateral flow immunoassay in rapid detection of influenza A virus.

METHODS

A total of 378 samples of nasopharyngeal secretions were collected from 378 children with influenza-like symptoms to detect the influenza A virus by fluorescence lateral flow immunoassay, colloidal gold immunoassay, and RT-PCR between July 2015 and August 2015.

RESULTS

Of the 378 samples, 81 (21.4%) were positive for influenza A virus by RT-PCR. Compared with RT-PCR, the sensitivities of fluorescence lateral flow immunoassay and colloidal gold immunoassay were 90.1% (73/81) and 75.3% (61/81), respectively, and the specificities were 99.3% (295/297) and 98.3% (292/297), respectively. The average threshold cycle (Ct) value for the positive samples detected by the fluorescence lateral flow immunoassay (30.6) was higher than that for the positive samples detected by the colloidal gold immunoassay (28.7).

CONCLUSIONS

Compared with colloidal gold immunoassay, fluorescence lateral flow immunoassay has higher sensitivity, specificity, and concordance rate with RT-PCR, suggesting that it can be used for early screening and diagnosis of influenza A.

[Influencing factors for duration of viral nucleic acid shedding in children with influenza A]

OBJECTIVE

To investigate the features and duration of viral nucleic acid shedding in children with influenza A.

METHODS

The clinical data of 90 children with influenza A with positive influenza A virus nucleic acid in nasopharyngeal swab detected by PCR were collected, and these children were divided into simple influenza A group (n=10), influenza A-pneumonia group (n=61), influenza A-nervous system damage group (n=10), and influenza A-underlying disease group (n=9). A retrospective analysis was performed for clinical features, treatment process, duration of viral nucleic acid shedding, and prognosis.

RESULTS

The most common symptoms in these children were fever (89/90, 99%), cough (89/90, 99%), running nose (69/90, 77%), shortness of breath (26/90, 29%), and myalgia (23/90, 26%). The mean duration of viral nucleic acid shedding in 90 children was 9.4±2.9 days. The simple influenza A group had a significantly shorter duration of viral nucleic acid shedding than the influenza A-pneumonia, influenza A-nervous system damage, and influenza A-underlying disease groups (p<0.05), while there were no significant differences between the influenza A-pneumonia, influenza A-nervous system damage, and influenza A-underlying disease groups (p>0.05). The children who received antiviral therapy within 48 hours after disease onset had significantly shorter duration of viral nucleic acid shedding and time to body temperature recovery than those who received antiviral therapy more than 48 hours after disease onset (p<0.05). Of all the children with body temperature recovery, 83% still tested positive for viral nucleic acid.

CONCLUSIONS

Complications, underlying diseases, and timing of antiviral therapy are influencing factors for the duration of influenza A virus nucleic acid shedding, and whether body temperature returns to normal cannot be used to decide whether to continue antiviral therapy.

Novel reassortant influenza A(H5N8) viruses among inoculated domestic and wild ducks, South Korea, 2014

An outbreak of highly pathogenic avian influenza, caused by a novel reassortant influenza A (H5N8) virus, occurred among poultry and wild birds in South Korea in 2014. The aim of this study was to evaluate the pathogenesis in and mode of transmission of this virus among domestic and wild ducks. Three of the viruses had similar pathogenicity among infected domestic ducks: the H5N8 viruses were moderately pathogenic (0%-20% mortality rate); in wild mallard ducks, the H5N8 and H5N1 viruses did not cause severe illness or death; viral replication and shedding were greater in H5N8-infected mallards than in H5N1-infected mallards. Identification of H5N8 viruses in birds exposed to infected domestic ducks and mallards indicated that the viruses could spread by contact. We propose active surveillance to support prevention of the spread of this virus among wild birds and poultry, especially domestic ducks.

Gene Therapy for Respiratory Viral Infections

Pulmonary infections by viruses may result in serious diseases of public health importance. The problems of the infections are exacerbated by rapid transmission of the pathogenic agents, which occur through inhalation and direct contact with contaminated surfaces. Moreover, cross-species transmission resulting from changes to viral genetic makeup poses a risk for emergence of pathogens with new characteristics, which in some cases may be responsible for causing different diseases. With the advent of efficient sequencing and nucleic acid-based virus-disabling technologies, gene therapy is well placed to advance new treatments to counter respiratory infections. Most studies aimed at using nucleic acids to treat respiratory viral infections have used RNA interference (RNAi) to silence viral gene targets. A few studies have used silencing of host factors required by the viruses as a means of inhibiting viral replication and preventing emergence of escape mutants. By administering antivirals to the airways, studies performed in vivo have taken advantage of the anatomy of the respiratory system to deliver therapeutic nucleic acids. Reported data have shown proof of principle of efficacy of gene therapy in models of respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus, influenza virus A, and measles virus, among others. RNAi-based gene therapy has been advanced to clinical trial for treatment of RSV infection. Although the primary endpoint was not met in an intent-to-treat analysis, the investigation has provided useful information for the advancement of gene therapy for current and emergent respiratory infections.

Hospitalizations from pandemic Influenza [A(H1N1)pdm09] infections among type 1 and 2 diabetes patients in Spain

OBJECTIVES

To describe and analyze the clinical characteristics and outcomes for all patients with diabetes who were hospitalized with laboratory-confirmed A(H1N1)pdm09 infections in Spain during 2009.

METHODS

Observational retrospective study using data collected by the Spanish National Hospital Discharge Database. We selected all admissions with diagnosis ICD-9-CM code 488·1 [A(H1N1)pdm09]. Discharges were grouped as follows: no diabetes, Type1 and Type 2 diabetes. Underlying medical conditions and risk factors included all those that constitute an indication for annual influenza vaccination, pregnancy, and obesity. The outcome variables analyzed were in-hospital case fatality risk, length of hospital stay, and costs.

RESULTS

The total number of persons hospitalized with A(H1N1)pdm09 was 11,499. Of those, 97 suffered Type 1 and 936 Type 2, giving an overall prevalence of diabetes of 9%. The most common underlying medical condition among Type 2 subjects was obesity (26·8%), and for Type 1 renal disease (10·3%). In-hospital mortality was 2·1% among Type 1 patients, 3·8% among Type 2 patients, and 2·3% among non-diabetics; after multivariate analysis, diabetes was not a factor independently associated with dying during hospitalization for A(H1N1)pdm09. Independent factors increasing the risk of death among diabetic patients included age (OR 1·03; 95% CI1·01-1·05), hematological disorders (OR 3·49; 95% CI, 1·46-8·37), and obesity (OR 1·88; 95% CI1·07-3·92).

CONCLUSIONS

Among individuals hospitalized in Spain with A(H1N1)pdm09 infections, the age-specific prevalence of diabetes was higher than the general population in most age groups. The results of multivariate analysis suggest that possibly concomitant conditions such as obesity increase the risk of dying from the infection, but not diabetes itself.

High morbidity and mortality associated with an outbreak of influenza A(H3N2) in a psycho-geriatric facility

In spring 2008, an influenza A subtype H3N2 outbreak occurred in a long stay psycho-geriatric ward and two wards in the intellectual disability services (IDS), part of a large psychiatric hospital. The attack rate in the index ward was 90% (18/20) for patients and 35% (7/20) for staff. It was 14% (1/7) and 17% (2/12) in the affected IDS wards for patients and 0% (0/20) and 4% (1/25) for staff. Many of the laboratory-confirmed cases did not have a fever >38 °C, a typical sign of influenza. Control measures included oseltamivir treatment for cases and prophylaxis for contacts, standard and droplet infection control precautions, active surveillance for early detection and isolation of potential cases. As a result, the outbreak did not spread throughout the hospital. Although the staff vaccination rate (10%) prior to the outbreak was low, we observed a much lower vaccine effectiveness rate in the patients (11%) than in the staff (100%) in the index ward. Vaccination of residents and staff of such facilities remains the key influenza prevention strategy.

Safety and immunogenicity of a plant-produced recombinant hemagglutinin-based influenza vaccine (HAI-05) derived from A/Indonesia/05/2005 (H5N1) influenza virus: a phase 1 randomized, double-blind, placebo-controlled, dose-escalation study in healthy adults

Recently, we have reported [1,2] on a subunit influenza vaccine candidate based on the recombinant hemagglutinin protein from the A/Indonesia/05/2005 (H5N1) strain of influenza virus, produced it using 'launch vector'-based transient expression technology in Nicotiana benthamiana, and demonstrated its immunogenicity in pre-clinical studies. Here, we present the results of a first-in-human, Phase 1 randomized, double-blind, placebo-controlled study designed to investigate safety, reactogenicity and immunogenicity of three escalating dose levels of this vaccine, HAI-05, (15, 45 and 90 µg) adjuvanted with Alhydrogel® (0.75 mg aluminum per dose) and the 90 µg dose level without Alhydrogel®. Vaccine was administered intramuscularly in two injections three weeks apart to healthy adults of 18-49 years of age. At all dose levels the vaccine was generally safe and well tolerated, with no reported serious adverse events or dose-limiting toxicities. Mild local and systemic reactions were observed in all vaccine dose groups and the placebo group and their occurrence was not dose related. The incidence rates were higher in the groups receiving vaccine with Alhydrogel®. The immune response elicited by the HAI-05 vaccine was variable with respect to both hemagglutination-inhibition and virus microneutralization antibody titers, with the highest responses observed in the 90 µg unadjuvanted group.

Full genomic analysis of an influenza A (H1N2) virus identified during 2009 pandemic in Eastern India: evidence of reassortment event between co-circulating A(H1N1)pdm09 and A/Brisbane/10/2007-like H3N2 strains

BACKGROUND

During the pandemic [Influenza A(H1N1)pdm09] period in 2009-2010, an influenza A (Inf-A) virus with H1N2 subtype (designated as A/Eastern India/N-1289/2009) was detected from a 25 years old male from Mizoram (North-eastern India).

OBJECTIVE

To characterize full genome of the H1N2 influenza virus.

METHODS

For initial detection of Influenza viruses, amplification of matrix protein (M) gene of Inf-A and B viruses was carried out by real time RT-PCR. Influenza A positive viruses are then further subtyped with HA and NA gene specific primers. Sequencing and the phylogenetic analysis was performed for the H1N2 strain to understand its origin.

RESULTS

The outcome of this full genome study revealed a unique reassortment event where the N-1289 virus acquired it's HA gene from a 2009 pandemic H1N1 virus with swine origin and the other genes from H3N2-like viruses of human origin.

CONCLUSIONS

This study provides information on possibility of occurrence of reassortment events during influenza season when infectivity is high and two different subtypes of Inf-A viruses co-circulate in same geographical location.

Emergence of pandemic 2009 influenza A H1N1, India

BACKGROUND & OBJECTIVES

Pandemic H1N1 caused deluge of cases from 74 countries and prompted World Health Organization to raise warning to phase 6. The present study was conducted on throat and nasal swab samples received and tested at National Centre for Disease Control, Delhi, India during 2009-2010 to collect epidemiological and clinical information on positive cases.

METHODS

Throat and nasopharyngeal swabs from category C influenza A H1N1 patients during May 2009-September 2010 along with their clinico-epidemiological details were collected from identified hospitals from Delhi and other States. Samples were tested by Real time reverse transcriptase PCR using primers and probes developed at CDC, Atlanta for four influenza target genes.

RESULTS

A total of 33,751 samples, both throat and nasal swab samples from each patient were tested for H1N1 influenza virus, of which, 7943 (23.5%) were positive for pandemic influenza A H1N1 and 3759 (11.1%) were positive for influenza A (seasonal flu). Maximum number of positive cases (N=2792, 35.1%) were from 20-39 yr age group, comprising 1790 (22.5%) males and 1182 (14.8%) females. Only 2620 (33%) positive cases were close contact of influenza A H1N1 positive patient. Majority cases presented (N=2792, 35.1%) with fever 7005 (88.1%), followed by 6133 cases (77.2%) exhibiting fever and cough, 377 (4.7%) complained of fever, cough, nasal catarrh and 362 (4.5%) cases had fever with shortness of breath.

INTERPRETATION & CONCLUSIONS

The study showed a peak of cases of pandemic influenza A H1N1 in December 2009 and indicated predominance of H1N1 positive cases among 20-39 yr age group and among males compared to females.

Clinical and epidemiological characteristics of 2009 pandemic influenza A in hospitalized pediatric patients of the Saurashtra region, India

BACKGROUND

The first case of 2009 pandemic influenza A or H1N1 virus infection in India was reported in May 2009 and in the Saurashtra region in August 2009. We describe the two waves clinicoepidemiological characteristics of children who were hospitalized with 2009 influenza A infection in the Saurashtra region.

METHODS

From September 2009 to February 2011, we treated 117 children infected with 2009 influenza A virus who were admitted in different hospitals in Rajkot city. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) test was used to confirm infection, and the clinico-epidemiological features of the disease were closely monitored.

RESULTS

In the 117 patients, with a median age of 2 years, 59.8% were male. The median time from onset of the disease to influenza A diagnosis was 5 days, and that from onset of the disease to hospitalization was 7 days. The admitted patients took oseltamivir, but only 11.1% of them took it within 2 days after onset of the disease. More than one fourth (29.1%) of the admitted patients died. The most common symptoms of the patients were cough (98.3%), fever (94.0%), sore throat and shortness of breathing. Pneumonia was detected by chest radiography in 80.2% of the patients.

CONCLUSIONS

In children with infection-related illness, the survival rate was about 71% after oseltamivir treatment. The median time for virus detection with real-time RT-PCR is 5 days. Early diagnosis and treatment may reduce the severity of the disease.

Neurological complications of pandemic influenza A H1N1 2009 infection: European case series and review

Neurological manifestations and outcomes of children with the 2009 H1N1 virus infection have been reported in three American series and from smaller cohorts and case reports worldwide. Of the 83 children admitted between April 2009 and March 2010 with H1N1 virus infection to a tertiary children's hospital in a European setting, five children aged between 2 and 10 years had neurological symptoms. Four patients had seizures and encephalopathy at presentation. One patient presented with ataxia; one developed neuropsychiatric manifestations, and two developed movement disorders during the disease course. Early neuroimaging showed evidence of acute necrotising encephalopathy (ANE) in one case and non-specific white matter changes in another. Initial neuroimaging was normal for the other three, but interval MRI showed increased signal in bilateral periventricular distribution in one and significant cerebral volume loss in the other. Clinical outcomes varied: two recovered fully while three had residual seizures and/or significant cognitive deficits. Conclusion An analysis of our patients along with all reported cases reveal that seizures and encephalopathy were common neurological presentations associated with pandemic 2009 H1N1 influenza virus infection in children requiring hospital admission. Neuroimaging suggestive of ANE, basal ganglia involvement and volume loss appears to be associated with worse neurological outcome.

Cross-reactive neutralizing antibody against pandemic 2009 H1N1 influenza a virus in intravenous immunoglobulin preparations

Prepandemic intravenous immunoglobulin (IVIG) and sera from Kawasaki disease patients treated with this IVIG were analyzed for 2009 H1N1-specific microneutralization and hemagglutination inhibition antibodies. All 6 different IVIG preparations tested had significant levels of cross-reactive-specific antibody at a concentration of 2.0 g/dL of immunoglobulin. Sera from 18 of 19 Kawasaki disease patients had significant increases of cross-reactive-specific antibody after 2.0 g/kg of prepandemic IVIG. These results suggest a role for adjunctive IVIG therapy for severe and/or drug-resistant 2009 H1N1 virus and other highly antigenically drifted influenza strains, particularly in the immunocompromised.

Neonates investigated for influenza-like illness during the outbreak of pandemic H1N1 2009: trivial infections but major triage implications

We report eight cases of neonates (from birth to 25 days) admitted to the neonatal service of a teaching hospital with influenza-like illness during the outbreak of pandemic H1N1 2009, and discuss their management and infection control issues. Empirical antibiotics were often promptly initiated and timely stopped when sepsis was ruled out. Also, there was no pandemic H1N1-09 but influenza A (H3N2, n = 1), parainfluenza (type 3, n = 3) and respiratory syncytial virus (n = 1) have been isolated. The infants recovered spontaneously without any antiviral therapy. There was no outbreak of the respiratory infections in the neonatal service during the admissions. Respiratory viral infections can occur in neonates although the clinical course may be milder and nonspecific. Emergency room and frontline staff must be vigilant of the non-specific clinical features of infections with respiratory viruses in the neonates so that prompt triage and isolation can be implemented to avoid outbreaks in the neonatal service.

[Pandemic influenza A (H1N1)v in the intensive care unit: what have we learned?]

The characteristics of pandemic influenza 2009 differ from those of seasonal influenza. In Australia-New Zealand the number of admissions to the intensive care unit (ICU) increased by 15-fold in the southern winter. We compared the characteristics of the Spanish series of the first ICU admissions in July with those of series published in Canada and Australia-New Zealand up to October 2009. Unlike the situation in Spain, only half the admissions in Canada and Australia-New Zealand were due to primary viral pneumonia but bacterial pneumonia was much more frequent. In all series, young people, many of whom had no comorbidities, were the most frequently affected population. The most common comorbidities were obesity, chronic pulmonary disease, pregnancy and heart disease. Diagnosis through reverse-transcriptase polymerase chain reaction can have a false-negative rate of 10%. Shock and acute renal insufficiency were more frequent in the Spanish series. A total of 10-30% of patients required ICU admission and 6 of 10 patients required mechanical ventilation with a high frequency of failure of non-invasive ventilation (75%). Mortality was similar among the series (14-25%) but was higher in patients requiring mechanical ventilation (30%). Early oseltamivir administration (< 48h after symptom onset) has been associated with better outcome. Therefore, early administration of this drug in patients with risk factors or those who, although free from risk factors, show clinical progression, could reduce ICU admissions and mortality.

Aerosol transmission of influenza A virus: a review of new studies

Over the past few years, prompted by pandemic preparedness initiatives, the debate over the modes of transmission of influenza has been rekindled and several reviews have appeared. Arguments supporting an important role for aerosol transmission that were reviewed included prolonged survival of the virus in aerosol suspensions, demonstration of the low infectious dose required for aerosol transmission in human volunteers, and clinical and epidemiological observations were disentanglements of large droplets and aerosol transmission was possible. Since these reviews were published, several new studies have been done and generated new data. These include direct demonstration of the presence of influenza viruses in aerosolized droplets from the tidal breathing of infected persons and in the air of an emergency department; the establishment of the guinea pig model for influenza transmission, where it was shown that aerosol transmission is important and probably modulated by temperature and humidity; the demonstration of some genetic determinants of airborne transmission of influenza viruses as assessed using the ferret model; and mathematical modelling studies that strongly support the aerosol route. These recent results and their implication for infection control of influenza are discussed in this review.

Establishment of multiple sublineages of H5N1 influenza virus in Asia: implications for pandemic control

Preparedness for a possible influenza pandemic caused by highly pathogenic avian influenza A subtype H5N1 has become a global priority. The spread of the virus to Europe and continued human infection in Southeast Asia have heightened pandemic concern. It remains unknown from where the pandemic strain may emerge; current attention is directed at Vietnam, Thailand, and, more recently, Indonesia and China. Here, we report that genetically and antigenically distinct sublineages of H5N1 virus have become established in poultry in different geographical regions of Southeast Asia, indicating the long-term endemicity of the virus, and the isolation of H5N1 virus from apparently healthy migratory birds in southern China. Our data show that H5N1 influenza virus, has continued to spread from its established source in southern China to other regions through transport of poultry and bird migration. The identification of regionally distinct sublineages contributes to the understanding of the mechanism for the perpetuation and spread of H5N1, providing information that is directly relevant to control of the source of infection in poultry. It points to the necessity of surveillance that is geographically broader than previously supposed and that includes H5N1 viruses of greater genetic and antigenic diversity.

Birds, migration and emerging zoonoses: west nile virus, lyme disease, influenza A and enteropathogens

Wild birds are important to public health because they carry emerging zoonotic pathogens, either as a reservoir host or by dispersing infected arthropod vectors. In addition, bird migration provides a mechanism for the establishment of new endemic foci of disease at great distances from where an infection was acquired. Birds are central to the epidemiology of West Nile virus (WNV) because they are the main amplifying host of the virus in nature. The initial spread of WNV in the U.S. along the eastern seaboard coincided with a major bird migration corridor. The subsequent rapid movement of the virus inland could have been facilitated by the elliptical migration routes used by many songbirds. A number of bird species can be infected with Borrelia burgdorferi, the etiologic agent of Lyme disease, but most are not competent to transmit the infection to Ixodes ticks. The major role birds play in the geographic expansion of Lyme disease is as dispersers of B. burgdorferi-infected ticks. Aquatic waterfowl are asymptomatic carriers of essentially all hemagglutinin and neuraminidase combinations of influenza A virus. Avian influenza strains do not usually replicate well in humans, but they can undergo genetic reassortment with human strains that co-infect pigs. This can result in new strains with a marked increase in virulence for humans. Wild birds can acquire enteropathogens, such as Salmonella and Campylobacter spp., by feeding on raw sewage and garbage, and can spread these agents to humans directly or by contaminating commercial poultry operations. Conversely, wild birds can acquire drug-resistant enteropathogens from farms and spread these strains along migration routes. Birds contribute to the global spread of emerging infectious diseases in a manner analogous to humans traveling on aircraft. A better understanding of avian migration patterns and infectious diseases of birds would be useful in helping to predict future outbreaks of infections due to emerging zoonotic pathogens.

Structure of the transmembrane region of the M2 protein H(+) channel

The transmembrane domain of the M2 protein from influenza A virus forms a nearly uniform and ideal helix in a liquid crystalline bilayer environment. The exposure of the hydrophilic backbone structure is minimized through uniform hydrogen bond geometry imposed by the low dielectric lipid environment. A high-resolution structure of the monomer backbone and a detailed description of its orientation with respect to the bilayer were achieved using orientational restraints from solid-state NMR. With this unique information, the tetrameric structure of this H(+) channel is constrained substantially. Features of numerous published models are discussed in light of the experimental structure of the monomer and derived features of the tetrameric bundle.

Modulation of airway smooth muscle tone by protease activated receptor-1,-2,-3 and -4 in trachea isolated from influenza A virus-infected mice

Relaxant and contractile effects of the tethered ligand domain sequences of murine PAR-1, PAR-2, PAR-3 and PAR-4, and of the proteases thrombin and trypsin were examined in mouse isolated tracheal preparations. The epithelium- and cyclo-oxygenase-dependence of these effects and the potential modulatory effects of respiratory tract viral infection were also investigated. In carbachol-contracted preparations, trypsin, thrombin, and the tethered ligand domain sequences of murine PAR-1 (SFFLRN-NH(2)), PAR-2 (SLIGRL-NH(2)) and PAR-4 (GYPGKF-NH(2)), but not PAR-3 (SFNGGP-NH(2)), induced transient, relaxant responses that were abolished by the cyclo-oxygenase inhibitor indomethacin. Repeated administration of SFFLRN-NH(2), SLIGRL-NH(2) or GYPGKF-NH(2) (30 microM) was associated with markedly diminished relaxation responses (homologous desensitization), although there was no evidence of cross-desensitization between these peptides. The tethered ligand domain sequences for PAR-1 and PAR-4 induced a rapid, transient contractile response that preceded the relaxant response. Contractions were not inhibited by indomethacin and were not induced by either thrombin or trypsin. Influenza A virus infection did not significantly affect the responses induced by either the proteases or peptides. Furthermore, epithelial disruption caused by mechanical rubbing had no significant effect on responses to these PAR activators in preparations from either virus- or sham-infected mice. In summary, the proteases trypsin and thrombin, and peptide activators of PAR-1, PAR-2 and PAR-4 induced relaxant responses of mouse isolated tracheal smooth muscle preparations, which were mediated by a prostanoid, probably PGE(2). Interestingly, PAR-mediated relaxations were not significantly diminished following acute damage to the epithelium caused by mechanical rubbing and/or the respiratory tract viral pathogen, influenza A. British Journal of Pharmacology (2000) 129, 63 - 70.

Rapid interferon gamma-dependent clearance of influenza A virus and protection from consolidating pneumonitis in nitric oxide synthase 2-deficient mice

Viral infection often activates the interferon (IFN)-gamma-inducible gene, nitric oxide synthase 2 (NOS2). Expression of NOS2 can limit viral growth but may also suppress the immune system and damage tissue. This study assessed each of these effects in genetically deficient NOS2(-/-) mice after infection with influenza A, a virus against which IFN-gamma has no known activity. At inocula sufficient to cause consolidating pneumonitis and death in wild-type control mice, NOS2(-/-) hosts survived with little histopathologic evidence of pneumonitis. Moreover, they cleared influenza A virus from their lungs by an IFN-gamma-dependent mechanism that was not evident in wild-type mice. Even when the IFN-gamma-mediated antiviral activity was blocked in NOS2(-/-) mice with anti-IFN-gamma mAb, such mice failed to succumb to disease. Further evidence that this protection was independent of viral load was provided by treating NOS2(+/+) mice with the NOS inhibitor, Nomega-methyl-L-arginine (L-NMA). L-NMA prevented mortality without affecting viral growth. Thus, host NOS2 seems to contribute more significantly to the development of influenza pneumonitis in mice than the cytopathic effects of viral replication. Although NOS2 mediates some antiviral effects of IFN-gamma, during influenza infection it can suppress another IFN-gamma-dependent antiviral mechanism. This mechanism was observed only in the complete absence of NOS2 activity and appeared sufficient to control influenza A virus growth in the absence of changes in cytotoxic T lymphocyte activity.