Types of influenza viruses. Tosh PK expert opinion. Mayo Clinic. Influenza vaccination. Mayo Clinic; Guide for considering influenza testing when influenza viruses are circulating in the community. Renaud DL expert opinion. Mayo Clinic, Rochester, Minn. Reye syndrome. Merck Manual Professional Version. Ibuprofen drug facts label. Food and Drug Administration. Acetaminophen oral. Prevent seasonal flu. Accessed Oct. Frequently asked influenza flu questions: season.
Recommendations for prevention and control of influenza in children, Sullivan JE, et al. Clinical report — Fever and antipyretic use in children. Reaffirmed July Labeling of drug preparations containing salicylates.
Electronic Code of Federal Regulations. Accessed Feb. Related Flu masks Flu vaccine: Safe for people with egg allergy? Show more related content. This book is distributed under the terms of the Creative Commons Attribution 4. Turn recording back on.
National Center for Biotechnology Information , U. StatPearls [Internet]. Search term. H1N1 Influenza Talha N. Author Information Authors Talha N. Continuing Education Activity H1N1 influenza is a subtype of influenza A virus, a communicable viral illness which causes upper and in some cases lower respiratory tract infections in its host. Introduction H1N1 Swine flu is a subtype of influenza A virus a communicable viral disease , which causes upper, and potentially, lower respiratory tract infections in the host it infects, resulting in symptoms such as nasal secretions, chills, fever, decreased appetite, and possibly lower respiratory tract disease.
Etiology The H1N1 influenza virus is an orthomyxovirus and produces virions that are 80 to nm in diameter, with an RNA genome size of approximately The swine influenza genome has 8 different regions which are segmented and encode 11 different proteins: Envelope proteins hemagglutinin HA and neuraminidase NA.
Epidemiology Swine flu was first isolated from pigs in the s by researchers in the United States and was subsequently recognized by pork producers and veterinarians as a cause of flu infections in pigs worldwide, and for the next 60 years, H1N1 was the predominant swine influenza strain.
People who have a higher risk of becoming seriously ill if infected include: Children younger than 5 years old. Adults older than age 65, younger adults, and children under age 19 who are on long-term aspirin therapy. 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. Experimental infection with a Thai reassortant swine influenza virus of pandemic H1N1 origin induced disease.
Virol J. Epub Mar Is it a policy crisis or it is a health crisis? These small changes occur at a relatively stable rate in all influenza viruses. As a result, scientists can compare the number of mutations found within a new influenza virus with older, related influenza viruses to estimate the amount of time that it may have taken for one strain to evolve into a new strain of influenza virus.
Researchers at CDC used this molecular evolution method to determine that the H1N1 influenza virus likely evolved in nature — perhaps through circulation in an unknown animal host — for a number of years before being detected.
Research so far suggests that the H1N1 influenza virus is changing at a normal rate as compared to other influenza viruses. The H1N1 influenza virus does not have the adaptations that are typical of influenza viruses grown or created in laboratories. For example, the standard method of growing influenza virus in laboratories involves injecting the virus into fertilized chicken eggs.
The H1N1 influenza virus lacks the properties associated with growth in eggs. Prior to the discovery of the H1N1 influenza virus, this particular combination of gene segments from North American and Eurasian swine had never been detected before in a single influenza virus and this new virus is different from the influenza viruses that normally circulate in North American and Eurasian pigs. It is not known when reassortment occurred to create the H1N1 influenza virus.
Testing of the virus suggests that this reassortment event may have occurred years prior to the first reports of H1N1 influenza infection in people. Pigs can be infected by influenza viruses found in birds and other animals as well as people.
Therefore, pigs represent a mixing vessel in which influenza viruses from different species can swap genes. For example, in a setting where people and animals are in close contact, pigs can be infected by influenza viruses found in pigs, poultry or humans — sometimes at the same time. However, in the late s, a series of reassortment events occurred between influenza viruses found in pigs, humans and birds.
As a result, swine influenza viruses with genes from humans, North American pigs and birds have existed in many parts of the world for around 10 years prior to H1N1 flu. This is very unlikely. Each of the gene segments within the H1N1 influenza virus have been found in pigs for more than 10 years prior to the beginning of the H1N1 influenza outbreak. In addition, a Nature study showed that reassortment between influenza viruses found in North American and Eurasia pigs had already occurred at least once naturally in the 5 years prior to the identification of H1N1 flu.
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