Love words? Need even more definitions? Merriam-Webster's Words of the Week - Jan. Ask the Editors 'Everyday' vs. What Is 'Semantic Bleaching'? How 'literally' can mean "figuratively". Literally How to use a word that literally drives some pe Influenza A viruses are classified by subtypes based on the properties of their hemagglutinin H or HA and neuraminidase N or NA surface proteins. There are 18 different HA subtypes and 11 different NA subtypes.
Subtypes are named by combining the H and N numbers — e. Click on the image to enlarge the picture. There are four types of influenza viruses: A, B, C and D. Human influenza A and B viruses cause seasonal epidemics of disease known as flu season almost every winter in the United States. Influenza A viruses are the only influenza viruses known to cause flu pandemics, i. A pandemic can occur when a new and different influenza A virus emerges that both infects people and has the ability to spread efficiently among people.
Influenza C virus infections generally cause mild illness and are not thought to cause human epidemics. Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.
Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin H and neuraminidase N. There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes H1 through H18 and N1 through N11, respectively.
Reassortment can occur when two influenza viruses infect a host at the same time and swap genetic information. This graphic shows the two types of influenza viruses A and B that cause most human illness and that are responsible for flu seasons each year.
Both influenza A and B viruses can be further classified into clades and sub-clades which are sometimes called groups and sub-groups. Preventing the flu and reducing the severity of flu illness and hospitalizations could also lessen the number of people needing to stay in the hospital. The flu vaccine is available as an injection and as a nasal spray.
The nasal spray is approved for use in healthy people ages 2 through 49 years old. The nasal spray isn't recommended for some groups, such as pregnant women, children between 2 and 4 years old with asthma or wheezing, and people who have compromised immune systems. For example, you may need to practice social distancing physical distancing and stay at least 6 feet 2 meters from others outside your household. You may also need to wear a cloth face mask when around people outside your household.
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Overview The H1N1 flu, commonly known as swine flu, is primarily caused by the H1N1 strain of the flu influenza virus. More Information Self-care for the flu. Request an Appointment at Mayo Clinic. More Information He's the bravest kid I've ever seen. More Information Flu masks Flu vaccine: Safe for people with egg allergy? Share on: Facebook Twitter. Show references Key facts about human infections with variant viruses.
Centers for Disease Control and Prevention. People suffering from chronic diseases such as asthma, heart disease, diabetes mellitus, or neuromuscular disease. Pathophysiology H1N1 swine flu is an acute disease that infects the upper respiratory tract and can cause inflammation of the upper respiratory passages, trachea, and possibly the lower respiratory tract. Histopathology Swine flu causes most symptoms in upper and lower respiratory tracts. History and Physical The history and clinical presentations of H1N1 swine influenza have ranged from mild flu symptoms to severe respiratory symptoms and possibly death depending on the age of the patient, co-morbidities, vaccination status, and natural immunity in patients to the virus.
Evaluation Influenza A H1N1 virus infection could be encountered in a wide range of clinical settings and may result in variable pathologic findings. Prevention of swine flu in swine: Main methods to prevent swine flu in pigs involve facility management using disinfectants and regulated temperature to control viruses in the environment , herd management not adding pigs possibly carrying influenza to the herds that have not yet been exposed to the virus , and vaccination. As much of the morbidity and mortality observed with swine flu is due to secondary infection by other pathogens, strategies that solely rely on vaccination may be insufficient.
Prevention of swine to human viral transmission: Because swine can be infected with avian and human strains of H1N1 influenza, they are the primary hosts where antigenic shifts occur that can cause new strains of swine flu.
Transmission of the influenza virus from swine to humans is usually seen in people who have a close association with pigs, such as farmers, pork handlers, and veterinarians. These individuals are strongly encouraged to wear face-masks when dealing with the animals to prevent transmission through respiratory droplets. The most important step of prevention is vaccination of the swine.
Individuals with increased risk of acquiring swine flu through pigs are those who smoke and do not wear gloves or masks when dealing with infected animals, increasing the risk of possible hand-to-nose, hand-to-eye, or hand-to-mouth transmission. Prevention of human to human transmission: The main route of swine flu virus spread between humans is exposure to the virus when someone infected sneezes or coughs, and the virus enters one of the potential mucous surfaces, or when a person touched something infected with the virus and subsequently touch their nose, mouth, and surrounding areas.
Swine flu is most contagious in the first 5 days of illness in most people, although this may increase in children and the elderly. Current CDC recommendations to prevent the spread of the virus include frequent handwashing with soap and water or alcohol-based sanitizers, and also disinfecting household, hospital and public settings by cleaning with a diluted bleach solution. Anyone who resides in an area where the disease is prevalent and suspects an infection or presents with flu-like symptoms, should stay away from work and public transportation and immediately see a doctor.
Differential Diagnosis Acute respiratory distress syndrome. Prognosis Evaluation of data reveals that some patients admitted with swine flu are at risk for sepsis, ARDS and death. Enhancing Healthcare Team Outcomes Swine flu is very contagious and is easily spread from humans after contact with pigs.
Review Questions Access free multiple choice questions on this topic. Comment on this article. References 1. Lessons learnt from the Indian H1N1 swine flu epidemic: Predictors of outcome based on epidemiological and clinical profile. J Family Med Prim Care. Ann Glob Health. Keenliside J. Pandemic influenza A H1N1 in Swine and other animals. Curr Top Microbiol Immunol. J Virol. Swine influenza viruses in Northern Vietnam in Emerg Microbes Infect. Vet Res. Emerg Infect Dis. Nickol ME, Kindrachuk J.
A year of terror and a century of reflection: perspectives on the great influenza pandemic of BMC Infect Dis. Pathology of the swine-origin influenza A H1N1 flu. Pathol Res Pract. The impact of influenza virus infection in pregnancy. Future Microbiol. Cases of swine influenza in humans: a review of the literature. Clin Infect Dis. H1N1 influenza virus infection results in adverse pregnancy outcomes by disrupting tissue-specific hormonal regulation.
PLoS Pathog. Closure of schools during an influenza pandemic. Lancet Infect Dis. H1N1 Influenza. In: StatPearls [Internet]. In this Page. Related information. Similar articles in PubMed.
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