Influenza infections in Australia 2009-2015: is there a combined effect of age and sex on susceptibility to virus subtypes?

BACKGROUND: Influenza is a global infectious disease with a large burden of illness and high healthcare costs. Those who experience greater burden of disease include younger and older people, and pregnant women. Although there are known age and sex susceptibilities, little is known about how the interaction of age and sex may affect a population's vulnerability to infection with different subtypes of influenza virus. METHODS: Laboratory-confirmed cases of influenza notified between 1 January 2009 and 31 December 2015 obtained from the Australian Government National Notifiable Diseases Surveillance System Influenza Public Data Set were analysed by age, sex and virus subtype. Age standardised notification rates per 100,000 population were calculated separately for females and males and used to generate female-to-male ratios with 95% confidence intervals for influenza A and B, and for virus subtypes A(H1N1)pdm09 and A(H3N2). RESULTS: 334,560 notifications for influenza A (all notifications), A(H1N1)pmd09, A(H3N2) and B subtypes from a total of 335,414 influenza notifications were analysed. Male notification rates were significantly higher for the 0 to 4 years old age group regardless of virus type or subtype; and higher for those aged 0 to 14 years and those 85 years and older for influenza types A and B and subtype A(H1N1)pdm09. Female notification rates were significantly higher for A(H1N1)pdm09 in those aged 15 to 54 years, for Type A and sub-type A(H3N2) in those aged 15 to 69 years, and for Influenza B in those aged 20 to 74 years. CONCLUSIONS: We observed a female dominance in notification rates throughout the adult age groups, which could possibly be related to health seeking behaviours. However, differences in health seeking behaviours cannot explain the variations observed across virus subtypes in the particular age groups with higher female notifications. Depending on their age, females may be more susceptible to certain subtypes of influenza virus. These observations suggest that there is an interaction between age and sex on susceptibility to influenza infection which varies by the subtype of the virus. The inclusion of pregnancy and menopausal status in surveillance data may assist development of targeted public health approaches during the emergence of new subtypes of influenza virus. Targeted vaccination campaigns may need to take into consideration specific age and sex groups who have a greater susceptibility to influenza infection as well as those who experience a greater burden of illness.

Biochemical features of a catalytic antibody light chain, 22F6, prepared from human lymphocytes.

Human antibody light chains belonging to subgroup II of germ line genes were amplified by a seminested PCR technique using B-lymphocytes taken from a human adult infected with influenza virus. Each gene of the human light chains was transferred into the Escherichia coli system. The recovered light chain was highly purified using a two-step purification system. Light chain 22F6 showed interesting catalytic features. The light chain cleaved a peptide bond of synthetic peptidyl-4-methyl-coumaryl-7-amide (MCA) substrates, such as QAR-MCA and EAR-MCA, indicating amidase activity. It also hydrolyzed a phosphodiester bond of both DNA and RNA. From the analysis of amino acid sequences and molecular modeling, the 22F6 light chain possesses two kinds of active sites as amidase and nuclease in close distances. The 22F6 catalytic light chain could suppress the infection of influenza virus type A (H1N1) of Madin-Darby canine kidney cells in an in vitro assay. In addition, the catalytic light chain clearly inhibited the infection of the influenza virus of BALB/c mice via nasal administration in an in vivo assay. In the experiment, the titer in the serum of the mice coinfected with the 22F6 light chain and H1N1 virus became considerably lowered compared with that of 22F6-non-coinfected mice. Note that the catalytic light chain was prepared from human peripheral lymphocyte and plays an important role in preventing infection by influenza virus. Considering the fact that the human light chain did not show any acute toxicity for mice, our procedure developed in this study must be unique and noteworthy for developing new drugs.

Pneumocystis jirovecii Pneumonia Complicated by Pneumomediastinum: A Case Report.

Pneumomediastinum refers to the presence of air in the mediastinum (the space in the chest between the lungs). It can arise from various etiologies, including trauma, esophageal perforation, infections, medical procedures, or underlying lung diseases. Pneumocystis jirovecii pneumonia (PJP) is a common opportunistic infection seen in immunocompromised individuals, especially those with HIV/AIDS. Pneumomediastinum is a rare but serious complication of PJP that occurs in immunosuppressed patients, leading to significant morbidity and mortality. We present a rare case of pneumomediastinum caused by P. jirovecii pneumonia in an AIDS patient.

The Utility of Troponin Dynamics in Influenza Myopericarditis: A Literature Review.

Influenza, typically recognized as a respiratory ailment, can manifest severe cardiac complications, notably, myocarditis and pericarditis, with potential fatal outcomes. Interestingly, influenza B demonstrates a reduced occurrence of troponin I elevation despite the risk of cardiac issues, such as isolated pericarditis. Interpreting the absence of troponin elevation as an indication of no cardiac involvement in cases of influenza B-related pericarditis may be contributing to poorer clinical outcomes. This trend may stem from the cellular tropism and unique affinity of certain influenza strains for pericardial cells rather than myocardiocytes. A thorough grasp of troponin dynamics in influenza is pivotal for customizing approaches aimed at improving clinical outcomes in myopericarditis cases.

A Critically Ill Influenza A-Positive Patient With Spontaneous Pneumomediastinum, Superimposed Bacterial Pneumonia, and Bilateral Pneumothoraces.

Influenza most often causes a febrile viral syndrome inclusive of pulmonary irritation with cough, shortness of breath, and congestion. However, severe infection can also occur, causing significant viral pneumonia with Type 1 respiratory failure. and rare but life-altering complications such as pneumomediastinum, secondary bacterial pneumonia, acute respiratory distress syndrome (ARDS), viremia, and death. This was a case of a 20-year-old male with no significant past medical history who presented to the emergency department with shortness of breath and chest discomfort and was found to have Influenza A with Type I respiratory failure requiring High Flow Nasal Cannula (HFNC) and extensive pneumomediastinum, superimposed bacterial pneumonia, and bilateral pneumothoraces. It is possible that complications secondary to influenza A infections could be under-reported due to the extremely high prevalence of the viral infection in this country. In addition, complicated pneumomediastinum from Influenza infection is sparsely documented in young adult males and children, but its clinical course can be dramatic enough to include life-altering complications. This case should serve as a reminder to all emergency medicine providers that when evaluating unstable Influenza A patients, various tests should be considered on a case-by-case basis to risk-stratify the likelihood of emergent pathology.

Natural Infection with Highly Pathogenic Avian Influenza A/H5N1 Virus in Pet Ferrets.

The study involved five ferrets from one household in Poland, comprising three sick 9-week-old juveniles, their healthy mother, and another clinically normal adult, admitted to the veterinary clinic in June 2023. The juvenile ferrets displayed significant lethargy and a pronounced unwillingness to move with accompanying pulmonary distress. Prompted by concurrent outbreaks of A/H5N1 influenza virus infections in Polish cats, point-of-care tests were conducted that revealed type A influenza antigens in the throat swabs of all five ferrets. Despite treatment, one juvenile ferret exhibited dyspnea and neurological symptoms and eventually died. The two remaining ferrets recovered fully, including one severely affected showing persistent dyspnea and incoordination without fever that recovered after 11 days of treatment. In the RT-qPCR, the throat swabs collected from all surviving ferrets as well as the samples of lungs, trachea, heart, brain, pancreas, liver, and intestine of the succumbed ferret were found positive for A/H5N1 virus RNA. To our best knowledge, this is the first documented natural A/H5N1 avian influenza in domestic ferrets kept as pets. In addition, this outbreak suggests the possibility of asymptomatic A/H5N1 virus shedding by ferrets, highlighting their zoonotic potential and the advisability of excluding fresh or frozen poultry from their diet to reduce the A/H5N1 virus transmission risks.

Miller-Fisher Syndrome Following Influenza A Infection.

Miller-Fisher syndrome (MFS), characterized by ophthalmoplegia, ataxia, and areflexia, is a Guillain-Barré syndrome (GBS) variant. It is well-known that the causative antibody for MFS is anti-GQ1b antibody. This report describes a rare case of MFS with not only anti-GQ1b antibodies but also anti-GT1a antibodies following Influenza A infection. The patient, a 47-year-old woman, contracted Influenza A three weeks before admission. She complained of double vision followed by areflexia, ataxia in the four extremities, and complete gaze palsy. She was treated with intravenous methylprednisolone pulse and intravenous immunoglobulin therapies. Her neurological symptoms were recovered after these immunotherapies.

Upper Respiratory Tract Disease in a Dog Infected by a Highly Pathogenic Avian A/H5N1 Virus.

In summer 2023, during an outbreak of highly pathogenic avian influenza (HPAI) in cats in Poland, a 16-year-old dog was presented to the veterinary clinic with persistent, debilitating, dry cough, submandibular lymphadenomegaly, mild serous nasal discharge, and left apical heart murmur. A preliminary diagnosis of kennel cough was made and the treatment with amoxicillin/clavulanic acid and dexamethasone was initiated. Due to the lack of improvement within 2 days, a blood check-up, thoracic radiography and ultrasonography, and echocardiography were performed. Moreover, a rapid test for orthomyxovirus type A antigen in a throat swab was carried out and proved positive. The result was verified using RT-qPCR, which yielded a positive result for A/H5N1 influenza virus and negative results for A/H1N1, A/H3N2, type B influenza, and SARS-CoV-2. This case indicates that HPAI should be considered as a differential diagnosis not only in cats, but also in dogs with upper respiratory tract disease, particularly in regions experiencing A/H5N1 avian influenza outbreaks.

Retrospective Comparison of Influenza and COVID-19-Associated Acute Respiratory Distress Syndrome (ARDS): An Experience From a Tertiary Care Hospital.

Background The COVID-19 pandemic has had a profound impact on global healthcare systems, often compared to seasonal influenza due to similarities in clinical presentation. This study aims to compare the clinical characteristics, comorbidities, and outcomes of critically ill patients with COVID-19 and those with influenza admitted to a tertiary care hospital in Islamabad, Pakistan. Methods This retrospective cohort study included 120 patients, 60 with confirmed COVID-19 and 60 with confirmed influenza, all of whom required ICU admission and mechanical ventilation between January 1, 2021, and January 1, 2024. Data were collected from electronic medical records, including demographic information, comorbidities, and clinical outcomes. Descriptive statistics were used to compare the two groups. Results The median age of COVID-19 patients was 55 years (range 30-78), while that of influenza patients was 58 years (range 31-80). Both groups had a slight male predominance (COVID-19: 66.7%, Influenza: 63.3%). Comorbidities were common in both groups, with 75.0% of COVID-19 patients and 83.3% of influenza patients having at least one comorbidity. The most common comorbidities included hypertension (COVID-19: 30.0%, Influenza: 33.3%) and diabetes (COVID-19: 20.0%, Influenza: 25.0%). Clinical outcomes revealed a higher mortality rate among influenza patients (43.3%) compared to COVID-19 patients (28.3%). ICU admission rates were identical for both groups at 66.7%, and mechanical ventilation was required for 66.7% of ICU-admitted patients in both groups. The presence of cardiovascular comorbidities significantly impacted patient outcomes, with higher mortality observed in influenza patients with such comorbidities (44.7%) compared to COVID-19 patients (28.9%). Conclusion This study highlights the significant burden of both COVID-19 and influenza on critically ill patients, particularly those with cardiovascular comorbidities. While influenza patients in this cohort exhibited higher mortality rates, both groups demonstrated substantial ICU admission rates and a need for mechanical ventilation.

Sternoclavicular Septic Arthritis Due to Invasive Pneumococcal Infection After Type A Influenza Virus Infection.

A 24-year-old female patient who had a type A influenza virus infection prior to admission visited our hospital complaining of a fever and right sternoclavicular pain. Blood culture was positive for penicillin-sensitive Streptococcus pneumoniae (pneumococcus). Magnetic resonance imaging of the right sternoclavicular joint (SCJ) showed a high signal intensity area on the diffusion-weighted images. Consequently, the patient was diagnosed with septic arthritis due to invasive pneumococcus. When a patient complains of gradually increasing chest pain after an influenza virus infection, SCJ septic arthritis should be considered in the differential diagnosis.

Systemic Capillary Leak Syndrome Induced by Influenza Type A Infection: A Case Report.

Rhabdomyolysis accompanying influenza virus infection is a notable extrapulmonary complication. We experienced a case of influenza type A followed by rhabdomyolysis and systemic capillary leak syndrome (SCLS). A 57-year-old man with no significant past medical history was diagnosed as having influenza type A six hours after fever onset, and treatment with oseltamivir was started. Shock, rhabdomyolysis, and acute kidney injury (AKI) progressed rapidly. At 53 hours after starting the oral treatment, intensive care was initiated, including ventilation management. In the acute phase, a large-dose replacement was given for the SCLS and continuous renal replacement therapy for AKI; both eventually healed without sequelae.

Frequency and Seasonal Variations of Viruses Causing Respiratory Tract Infections in Children Pre- and Post-COVID-19 Pandemic in Riyadh (2017-2022).

Introduction The COVID-19 pandemic has had a major impact on healthcare systems throughout the world. As the clinical and epidemiological features of COVID-19 share many similarities with other respiratory viruses in children, ensuring optimal management of different viral respiratory diseases is critical. The precautions taken to prevent COVID-19 have seemingly had an indirect effect on the seasonal variations of viral diseases and the frequency of relevant viruses. The seasonal irregularity of and uncertainty surrounding these infection peaks may affect the clinical prediction and management resources. Therefore, the aim of this study is to evaluate the impact of the COVID-19 pandemic on the frequency and seasonal variation of common respiratory viruses in children pre- and post-pandemic. Methodology This study utilizes a descriptive cross-sectional retrospective approach. A total of 726 samples collected from children below 14 years of age and admitted to King Abdulla bin Abdulaziz University Hospital between March 2017 and February 2022 were included in the present study to evaluate the impact of the COVID-19 pandemic on the frequency and seasonal variation of common respiratory viruses in children pre- and post-pandemic. The samples taken before March 15, 2020, were considered pre-COVID-19, and those taken from March 15, 2020, onward were considered post-COVID-19. The seasons were divided based on the months of the year as per the Saudi climate website (winter: December-February, spring: March-April, summer: May-August, and autumn: September-November). Results All nasopharyngeal swabs (NPS) for viral Polymerase chain reaction (PCR) multiplex that were done for all admitted children of age up to 14 years were included, and the total samples amounted to 726, There were 686 (94.4%) positive samples for viruses and 40 (5.5%) negative samples. The number of positive samples pre-COVID-19 pandemic was 494 (72%), and the number of positive samples post-COVID-19 pandemic was 192 (28%). The frequency of different viruses has decreased post-COVID-19 and seasonality has changed; Although Adenovirus, and influenza viruses have no big changes, but Human Rhino/enterovirus (HRE) has increased frequency post-COVID-19 (49%), while post-COVID-19 it was (29.1%). The seasonal peak for Respiratory Syncytial Virus (RSV) pre-COVID-19 showed mainly in winter (49%), while post-COVID-19 it showed no peak. Conclusion The frequency of most types of viruses is noted to be lesser in the post-COVID-19 period, most likely due to precautions followed during the pandemic. This is not the case for HRE which showed increasing frequency in post-COVID-19; However, there are clinically and statistically significant differences among seasonal peaks in Respiratory RSV, HRE, and Parainfluenza viruses (PIV) pre- and post-COVID-19 pandemic. RSV showed no peak in different seasons post-COVID-19, although its peak pre-COVID-19 was in winter and autumn; Additionally typical trend of HRE peak changed to be in Autumn and spring post-COVID-19 instead of winter pre-COVID-19.

A Rare Case of Fulminant Myocarditis Caused by COVID-19 and Influenza B Co-infection.

Coronavirus disease 2019 and influenza B can have similar presentations and are self-limited in most cases. They are rarely associated with fatal cardiovascular complications. Coronavirus and influenza B-induced myocarditis is a rare but reversible cause of cardiogenic shock. Early detection plus administration of antiviral agents and supportive care with mechanical circulatory support in the form of an intra-aortic balloon pump can be a lifesaving measure in myocarditis.

Potent antiviral activity of the extract of Elaeocarpus sylvestris against influenza A virus in vitro and in vivo.

BACKGROUND: Elaeocarpus sylvestris (Lour.) Poir. (Elaeocarpaceae) belongs to a genus of tropical and semitropical evergreen trees, which has known biological activities such as antiviral and immunomodulatory activities. However, its antiviral potential against influenza virus infection remains unknown. PURPOSE: In this study, we investigated the antiviral activity of the 50% aqueous ethanolic extract of E. sylvestris (ESE) against influenza A virus (IAV) infection, which could lead to the development of novel phytomedicine to treat influenza virus infection. METHODS: To investigate the in vitro antiviral activity of ESE and its main ingredients, 1,​2,​3,​4,​6-​penta-​O-​galloyl-ß-d-glucose (PGG) and geraniin (GE), the levels of viral RNAs, proteins, and infectious viral particles in IAV-infected MDCK cells were analyzed. Molecular docking analysis was performed to determine the binding energy of PGG and GE for IAV proteins. To investigate in vivo antiviral activity, IAV-infected mice were treated intranasally or intragastrically with ESE, PGG, or GE. RESULTS: ESE and its gallate main ingredients (PGG and GE) strongly inhibited the production of viral RNAs, viral proteins, and infectious viral particles in vitro. Also through the viral attachment on cells, polymerase activity, signaling pathway, we revealed the ESE, PGG, and GE inhibit multiple steps of IAV replication. Molecular docking analysis revealed that PGG and GE could interact with 12 key viral proteins (M1, NP, NS1 effector domain (ED), NS1 RNA-binding domain (RBD), HA pocket A, HA receptor-binding domain (RBD), NA, PA, PB1, PB2 C-terminal domain, PB2 middle domain, and PB2 cap-binding domain) of IAV proteins with stable binding energy. Furthermore, intranasal administration of ESE, PGG, or GE protected mice from IAV-induced mortality and morbidity. Importantly, oral administration of ESE suppressed IAV replication and the expression of inflammatory cytokines such as IFN-γ, TNF-α, and IL-6 in the lungs to a large extent. CONCLUSION: ESE and its major components (PGG and PE) exhibited strong antiviral activity in multiple steps against IAV infection in silico, in vivo, and in vitro. Therefore, ESE could be used as a novel natural product derived therapeutic agent to treat influenza virus infection.

Exploring the active ingredients and pharmacological mechanisms of the oral intake formula Huoxiang Suling Shuanghua Decoction on influenza virus type A based on network pharmacology and experimental exploration.

Objective: To investigate the active ingredients, underlying anti-influenza virus effects, and mechanisms of Huoxiang Suling Shuanghua Decoction (HSSD). Materials and methods: The therapeutic effect of HSSD were confirmed through the survival rate experiment of H1N1-infected mice. Then, the HSSD solution and the ingredients absorbed into the blood after treatment with HSSD in rats were identified by UPLC/Q-TOF MS, while the main contents of ingredients were detected by high performance liquid chromatography (HPLC). Next, a systems pharmacology approach incorporating target prediction, gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, and molecular docking were performed to screen out the active compounds and critical pathways of HSSD in treating influenza. According to prediction results, real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry assay were used to detect the mRNA and protein expression levels of critical targets in H1N1-infected mice lungs. Results: Huoxiang Suling Shuanghua Decoction improved the survival rate of H1N1-infected mice and prolonged the mice's lifespan. Besides, HSSD exerts an antivirus effect by decreasing the levels of hemagglutinin (HA) and nucleoprotein (NP) to inhibit the replication and proliferation of H1N1, reducing the lung pathological state, inhibiting the cell apoptosis in the lung, and regulating the abnormal responses of peripheral blood, including GRA, LYM, white blood cell (WBC), PLT, and hemoglobin (HGB). Then, 87 compounds in the HSSD solution and 20 ingredients absorbed into the blood after treatment with HSSD were identified. Based on this, combined with the network analysis and previous research on antivirus, 16 compounds were screened out as the active components. Moreover, 16 potential targets were predicted by network pharmacology analysis. Next, molecular docking results showed stable binding modes between compounds and targets. Furthermore, experimental validation results indicated that HSSD regulates the contents of Immunoglobulin A (IgA), Immunoglobulin M (IgM), and Immunoglobulin G (IgG) in serum, modulating the levels of IFN-γ, IL-6, IL-10, MCP-1, MIP-1α, and IP-10 in the lung tissue, and significantly decreasing the mRNA and protein expressions of TLR4, CD14, MyD88, NF-κB p65, HIF1 α, VEGF, IL17A, and IL6 in the lung tissue. Conclusion: Huoxiang Suling Shuanghua Decoction exerts an anti-influenza effect by affecting the expressions of mRNA and protein including TLR4, CD14, MyD88, NF-kB p65, HIF-1α, VEGF, IL17A, IL6, and inhibiting the accumulation of inflammation. Our study provided experimental pieces of evidence about the practical application of HSSD in treating influenza.

Influenza Myocarditis: A Literature Review.

Viral myocarditis is not uncommon but the role of the influenza virus in causing myocarditis is less studied. It is difficult to diagnose influenza myocarditis. Due to bacterial and viral co-infection during influenza outbreaks, it becomes more difficult to distinguish influenza myocarditis from other causes. Our article provides current information on influenza myocarditis. We did a literature search using appropriate terms and reviewed articles published by November 2020. Our study highlights the incidence of influenza myocarditis and the need to become aware of this condition, especially during epidemics and pandemics. Our study highlights that although influenza myocarditis is a rare condition, it can be fatal. There should be increased awareness about the condition. By the early diagnosis and treatment of influenza myocarditis, we can prevent fatal complications.

COVID-19 and Influenza Co-Infection: Report of Three Cases.

Influenza and coronavirus disease 2019 (COVID-19) are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 pandemic is caused by a novel virus - severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Influenza is an infectious respiratory disease, caused by influenza A and influenza B viruses. We describe the three cases of influenza and COVID-19 co-infection.

Early Initiation of Awake Veno-Venous Extracorporeal Membrane Oxygenation Can Attenuate Muscle Atrophy and Weakness in Acute Respiratory Distress Syndrome.

Patients with acute respiratory distress syndrome (ARDS) exhibit prominent muscle atrophy and weakness. Although these patients often require deep sedation to perform lung-protective ventilation, extracorporeal membrane oxygenation (ECMO) can keep patients awake and make mobilization possible. A 60-year-old man was treated with ECMO due to ARDS. A multidisciplinary team conducted mobilization with standing on day 3. During intensive care unit (ICU) stay, catabolism was ongoing (urinary titin: 24.1-38.4 pmol/mg Cr), but the rectus femoris muscle, measured by ultrasound, moderately decreased by 5.3%, 10.8%, and 13.0% on days 3, 5, and 7, respectively, with maintained Medical Research Council score of 58-60. Diaphragm thickness remained unchanged. On day 5, he was separated from ECMO. After ambulation training, he was discharged from ICU on day 7. He returned home without prominent physical dysfunction. Our experience indicates early initiation of awake ECMO can accompany mobilization and attenuate muscle atrophy and weakness in ARDS.

Analysis of the full-length genome of a novel strain of the H7N9 avian influenza virus.

The aim of the present study was to analyze the evolution and variation of a novel strain of the avian influenza virus. The virus-positive specimens [A/Changsha/2/2013 (H7N9)] from a patient infected with the novel avian influenza A (H7N9) virus was amplified by reverse transcription-PCR and the full genome was sequenced. The sequencing results were submitted to GenBank and then analyzed by phylogenetic tree analysis using BioEdit and Mega5 software. The phylogenetic tree of the hemagglutinin (HA) and neuraminidase genes revealed that A/Changsha/2/2013 (H7N9) and all the new H7N9 viruses in 2013 were in a large cluster, and their nucleotide evolutionary distances were closely associated. Phylogenetic tree analyses of the nucleoprotein and nonstructural genes demonstrated two main branches. One branch contained novel H7N9 viruses isolated from avian, human and environmental sources in different regions. The other branch contained three novel H7N9 virus strains isolated from environmental sources in Shanghai. All the phylogenetic trees of the matrix protein, polymerase acidic, polymerase basic protein 1 and polymerase basic protein 2 genes also showed two branches, with each branch including the novel H7N9 virus strains isolated from avian, human and environmental sources in different regions. Molecular characterization demonstrated that 52 novel H7N9 viruses sequenced to date contain the G228S and G186V mutations in the receptor binding site of the HA protein. The full-genome sequences of A/Changsha/2/2013 and analyses of its molecular characteristics suggest that the A/Changsha/2/2013 H7N9 virus strain has molecular characteristics that may facilitate adaptation of the virus to mammalian hosts and may even bind to human receptors.