what is the pathophysiology of influenza

Vaccination is effective in reducing the risk of influenza illness by 40% to 60% in the overall population when vaccine strains and circulating viruses are similar. from people who show D. Reduce the time spent in crowded places. The H7N9 influenza A virus infection results in lethal inflammation in the mammalian host via the NLRP3-caspase-1 inflammasome. Commun Biol. Clipboard, Search History, and several other advanced features are temporarily unavailable. Two serious adverse events (pleuropericarditis and vasovagal syncope) were assessed as possibly related to RIV vaccination. Learn. Examples of animals include, but are not limited to, wild birds, poultry, pigs, horses, mink, and ferrets. AAVRJ-22-57054(R); Published: 24-March-2022, DOI:10.35841/AAVRJ-6.2.107, Citation: Wang J. Pathophysiology of influenza virus in respiratory tract system. The best way to prevent flu is by getting a flu vaccineeach year. Therapies targeting these pathways may have efficacy later in the response, after traditional antivirals have been found to have reduced effects [13]. Influenza can primarily cause severe pneumonia, but it can also present in conjunction with or be followed by a secondary bacterial infection, most commonly by Staphylococcus aureus and Streptococcus pneumoniae. Adjuvant treatment with a mammalian target of rapamycin inhibitor, sirolimus, and steroids improves outcomes in patients with severe H1N1 pneumonia and acute respiratory failure. Chen R, Holmes EC. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. 5th edition. Influenza viruses are among the most common causes of human respiratory infections (2), and among the most significant because they cause high morbidity and mortality. Razzaghi H, Kahn K, Black C, et al. Influenza outbreaks have apparently occurred since at least the Middle Ages, if not since ancient times (3). Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). The flu A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year. These patients who develop pneumonia are more likely to be young (<5years old), old (>65years old), Caucasian, and nursing home residents; have chronic lung or heart disease and history of smoking; and are more commonly immunocompromised. In affected areas, alveolar macrophages are sometimes present in large numbers and may show mitotic activity. Lucke et al. Flu can cause mild to severe illness, and at times can lead to death. Moderate or severe acute illness (with or without fever) in a patient is considered a precaution to vaccination, although persons with minor illness may be vaccinated. Garg S, Jain S, Dawood FS, Jhung M, Perez A, D'Mello T, et al. Hong Kong SAR, China If you do come down with the flu, these measures may help ease your symptoms: Drink plenty of liquids. Positive staining was observed in bronchial epithelial cells; submucosal mucus glands of the trachea, bronchi, bronchioli; and in single cells in alveolar lumina (thought to represent sloughed bronchial epithelial cells, not alveolar lining cells). The flu typically causes 12,000 to 52,000 deaths a year in the United States, and RSV is the leading cause of pneumonia in babies under one. Match. Viruses are prevalent in non-ventilated hospital-acquired pneumonia. Hemophagocytosis was also reported in both the 1918 and 1957 pandemics (1, 20). Integration of clinical data, pathology, and cDNA microarrays in influenza virus-infected pigtailed macaques (. Walter E, Klein N, Wodi A. Mononuclear inflammatory cells may also stain positively. Although epidemiologic information has been limited, person-to-person transmission of H5N1 has been suggested in a few instances, usually involving family members. Characterization of the 1918 Spanish influenza virus matrix gene segment. Complications of flu can include bacterial pneumonia, ear infections, sinus infections and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. The time from when a person is exposed and infected with flu to when symptoms begin is about two days, but can range from about one to four days. Self WH, Balk RA, Grijalva CG, Williams DJ, Zhu Y, Anderson EJ, et al. Necrotic cells may also undergo phagocytosis by macrophages. Influenza virus infections among patients attending emergency department according to main reason to presenting to ED: a 3-year prospective observational study during seasonal epidemic periods. 2022 Oct 21;9:1016352. doi: 10.3389/fmolb.2022.1016352. They were among the only observers of the 1918 pandemic to reach such a conclusion (20). Another histologic feature of the later stages of influenza virus pneumonia is evidence of repair and fibrosis. LAIV is administered intranasally. Influenza virus affects the respiratory tract by direct viral infection or by damage from the immune system response. * The burden estimate for the 2020-2021 season was not calculated due to the uncharacteristically low level of influenza activity that season. Fodor E, Devenish L, Engelhardt OG, Palese P, Brownlee GG, Garcia-Sastre A. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle Intraalveolar edema and hemorrhage are outstanding features of influenza virus pneumonia. Infection with influenza viruses can be asymptomatic or result in disease that ranges from mild to severe. Some associations have also been observed between influenza virus infection and cardiac sequelae, including increased risk of myocardial disease in the weeks following influenza virus infection. Flu episodes have clearly happened since at slightest the Middle Ages, in the event that not since old times. If LAIV is not administered on the same day with other live vaccines, then at least 4 weeks should separate administration of LAIV and other live vaccines. Leukocyte infiltration of the hyperemic alveolar septa is always present in the early stages of influenza virus pneumonia. The primary mechanism of influenza pathophysiology is a result of lung inflammation and compromise caused by direct viral infection of the respiratory epithelium, combined with the effects of lung inflammation caused by immune responses recruited to handle the spreading virus (Table 1). Alveolar edema was also observed. You may be able to spread flu to someone else before you know you are sick, as well as when you are sick with symptoms. sharing sensitive information, make sure youre on a federal Some people, especially young children and people with weakened immune systems, might be able to infect others for an even longer time. Snyder MH, London WT, Maassab HF, Murphy BR. Accessed October 26, 2020. For example, in the 1976 exposure of a limited number of soldiers to a swine-adapted H1N1 influenza virus in Fort Dix, New Jersey, there was one death (60, 61). Hayden FG. During and after the 1957 pandemic, a number of excellent autopsy studies of influenza viral infection were reported (17, 18, 82, 83). The inability of the lung to perform its primary function of gas exchange can result from multiple mechanisms, including obstruction of the airways, loss of alveolar structure, loss of lung epithelial integrity from direct epithelial cell killing, and degradation of the critical extracellular matrix. Influenza infections are among the foremost common causes of human respiratory infections and among the foremost noteworthy since they cause tall horribleness and mortality. The soft palate is an important site of adaptation for transmissible influenza viruses. Wolbach performed large autopsy studies in Boston and at nearby Camp Devens during the pandemic (21) and in 1923 wrote. ( ) Stay away from sick people. Later stages may also show typical changes of organization and fibrosis, including interstitial fibrosis, and bronchiolitis obliterans (see Figure 9) with or without evidence of organizing pneumonia (19, 20, 74). See details about the laboratory diagnosis of influenza. The evolution of human influenza viruses. Flu vaccine has been shown to reduce flu related illnesses and the risk of serious flu complications that can result in hospitalization or even death. Self WH, Williams DJ, Zhu Y, Ampofo K, Pavia AT, Chappell JD, et al. MMWR 2006;55(No. Three types of influenza cause disease in humans. Adults age 65 years represented a majority of the averted deaths (80%) and hospitalizations (58%). Whether the typical spectrum of influenza pathology would be observed if additional pathology studies were performed remains unclear. Kumar A, Zarychanski R, Pinto R, Cook DJ, Marshall J, Lacroix J, et al. Antigenic drift is the primary reason people can get influenza more than once and why it is necessary to annually review and update the composition of influenza vaccines. Carly_Oetker. Luke C, Lakdawala S, Subbarao K. Influenza vaccinelive. Symptoms usually occur within 6 to 12 hours of IIV vaccination and last 1 to 2 days. In mice, infection with the 1918 virus produced a necrotizing bronchitis and bronchiolitis with a marked alveolitis, with infiltrates of neutrophils and macrophages. Changes in influenza viruses can take the form of antigenic drift or antigenic shift. To ensure maximum protection, vaccination should be administered before the onset of influenza activity in the community. This 1918 autopsy lung tissue sample was positive by RT-PCR for influenza A virus A/New York/1/1918 (53). Human illness from avian influenza H7N3, British Columbia. Bethesda, MD 20894, Web Policies The infection of mice with swine influenza virus. Early structural changes caused by influenza virus in the epithelium of the upper airway are variable, including cytonecrosis initially involving shrinkage and vacuolization, followed by desquamation of these cells into the luminal space. Additionally, obesity dampens some features of adaptive immunity that may delay viral clearance or increase susceptibility to initial infection [2931]. Influenza A viral replication peaks approximately 48 hours after inoculation into the nasopharynx and declines slowly, with little virus shed after about six days. Influenza A (H1N1) vs non-H1N1 ARDS: analysis of clinical course. Given the prominence of secondary bacterial infections (discussed in detail below) in influenza-associated disease, such host-directed therapies may have significant clinical utility [20]. Influenza infection and heart failure-vaccination may change heart failure prognosis? In January 2011, CDC estimated that the 2009 H1N1 caused illness in more than 60 million Americans, leading to more than 270,000 hospitalizations and 12,500 deaths. Youzbashi E, Marschall M, Chaloupka I, Meier-Ewert H. [Distribution of influenza C virus infection in dogs and pigs in Bavaria]. Cases of respiratory syncytial virus, or RSV, are surging nationwide. Morens DM, Fauci AS. The primary mechanism of influenza pathophysiology is a result of lung inflammation and compromise caused by direct viral infection of the respiratory epithelium, Safety monitoring of seasonal IIV over the course of many years has not detected a clear link to GBS. You may need to change your activity level, depending on your symptoms. Flu (influenza) is an infection of the nose, throat and lungs, which are part of the respiratory system. Critically ill patients with 2009 influenza A(H1N1) in Mexico. CDC. The The flu (short for influenza) is a viral respiratory disease that affects the throat, nose and lungs. Vaccine 2018;36(39):5916-25. Ren R, Wu S, Cai J, Yang Y, Ren X, Feng Y, et al. The pathologic anatomy of influenzal bronchopneumonia. An increase in mortality typically accompanies each annual influenza season. H&E-stained section of the lung from a 1957 influenza victim showing massive pulmonary edema and hemorrhage in early bronchopneumonia. Both authors wrote the first draft for this manuscript. Re-emergence of fatal human influenza A subtype H5N1 disease. 2013;17(1):R30. In contrast, Shope showed that both ferrets and swine were able to transmit the virus to contact animals (86, 88). In this group, no viral antigens or nucleic acids could be detected. in their review of 1918 pandemic autopsies (20). These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests. More common complications of influenza include secondary bacterial pneumonia (e.g., Streptococcus pneumoniae, Haemophilus influenzae, or Staphylococcus aureus), exacerbations of underlying respiratory conditions, otitis media, laryngotracheobronchitis, and bronchitis. One difference they noted was that acute alveolar edema was not as prominent a feature of influenza pneumonia as in 1918, although it was still observed. Complete separation of the remaining epithelium may be a histologic artifact. As in the overlying epithelium, changes consist of cytonecrosis and desquamation. Nicholls JM, Bourne AJ, Chen H, Guan Y, Peiris JS. Characterization of the reconstructed 1918 Spanish influenza pandemic virus. official website and that any information you provide is encrypted H&E-stained section of the lung from a 1918 influenza victim showing a pattern of necrotizing alveolitis. Its descendants circulated in humans until 1957 when they were replaced by an H2N2 subtype pandemic strain. (105) reported on the pathology of cynomolgus monkeys with a 1997 H5N1 virus. Quantius J, Schmoldt C, Vazquez-Armendariz AI, Becker C, El Agha E, Wilhelm J, et al. While more than 100 different viruses can cause a cold, only influenza virus types A, B, and C cause the flu . The flu A and B viruses that routinely spread in people are responsible for seasonal flu epidemics each year. Opie et al. Eventually, the inclusion of critical parcels of the aviation routes in an irresistible reaction, either by coordinate viral disease or by harm from the reacting safe framework, speaks to a physiological disappointment. Saving Lives, Protecting People, Transmission of Flu Viruses from Animals to People, Antigenic Characterization of Flu Viruses, Flu Virus Genome Sequencing and Genetic Characterization, Advanced Molecular Detection (AMD) and Flu, Reconstruction of the 1918 Flu Pandemic Virus, Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD), Reconstruction of the 1918 Influenza Pandemic Virus, 2022-2023 Preliminary In-Season Burden Estimate, Who is at Higher Risk of Flu Complications, Flu and COVID-19 Vaccine Coadministration, Who Should & Who Should NOT Get Vaccinated, Live Attenuated Influenza Vaccine (LAIV)/Nasal Spray Vaccine, Selecting Viruses for the Seasonal Influenza Vaccine, Flu Vaccine and People with Egg Allergies, Frequently Asked Questions on Vaccine Supply, Historical Reference of Vaccine Doses Distributed, Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN), Influenza and Other Viruses in the Acutely Ill (IVY), Respiratory Virus Transmission Network (RVTN), Randomized Assessment of Influenza Vaccine Efficacy Network (RAIVEN), How Vaccine Effectiveness and Efficacy are Measured, What People with a Staph Infection Should Know about Flu, Resources for Hosting a Vaccination Clinic, Overview of Influenza Surveillance in the United States, Influenza Hospitalization Surveillance Network (FluSurv-NET), Weekly U.S. The epithelial layer is desquamating, and necrotic epithelial cells are present in the lumen. First, the type of virus is designated (A, B, or C), then the host (if non-human), place of isolation, isolation number, and year of isolation (separated by slashes). Influenza A and B viruses have a similar structure, whereas influenza C is more divergent. However, vaccine should continue to be offered throughout the influenza season, even into January or later. Shirey KA, Lai W, Scott AJ, Lipsky M, Mistry P, Pletneva LM, et al. As these cells play a key role in the response to many bacterial infections, their loss may play a critical part in increasing susceptibility. The alveolar walls are necrotic, and alveolar air spaces contain edema fluid, desquamated epithelial cells, and inflammatory cells (original magnification 200). Viral infections presenting concurrently with bacterial pneumonia are now known to occur with a frequency of 30-50% in both adult and pediatric populations. An official website of the United States government. If you need to go back and make any changes, you can always do so by going to our Privacy Policy page. (85) reported such a case in 1973 in which an open lung biopsy revealed necrotizing bronchitis and bronchiolitis. Before In the past two pandemics and especially in interpandemic seasonal influenza cases, fatal cases tended to occur in people with underlying chronic illnesses or at the extremes of age (4, 8). III. Ultimately, the involvement of significant portions of the airways in an infectious response, either by direct viral infection or by damage from the responding immune system, represents a physiological failure. 2017;35(42):5618-5621. Reid AH, Fanning TG, Janczewski TA, Lourens RM, Taubenberger JK. Hospitalizations ( 58 % ) and in 1923 wrote gene segment be administered before the onset influenza!, Perez A, B, and ferrets structure, whereas influenza is. Pandemic autopsies ( 20 ) Camp Devens during the pandemic ( 21 and. 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what is the pathophysiology of influenza