After early outbreaks in North America in April the new influenza virus spread rapidly around the world. By the World Health Organizations official tally the flu pandemic of killed people around the world. During the pandemic the EOC gave CDC flu fighters and partners a place to exchange information and make decisions quickly. Causing enormous numbers of deaths and illness and a significant number. There has been considerable controversy over the past year particularly in Europe over whether the World Health Organization WHO changed its definition of pandemic influenza in after novel H1N1 influenza was identified.
Pandemic definition is - occurring over a wide geographic area such as multiple countries or continents and typically affecting a significant proportion of the population. This virus was designated as influenza A H1N1pdm09 virus. Viruses that have caused past pandemics typically originated from animal influenza viruses. Hong Kong Flu Wikipedia. Pin On Pandemics Epidemics. Widget Atas Posting.
Treanor JJ. Influenza viruses, including avian influenza and swine influenza. Philadelphia, PA: Elsevier; chap Updated by: Linda J. Editorial team. H1N1 influenza Swine flu. Any flu virus can spread from person to person when: Someone with the flu coughs or sneezes into air that others breathe in. Explain the importance of improving care coordination, with particular emphasis on communication between interprofessional medical teams, to enhance prompt and thorough delivery of care to patients with H1N1 influenza and prevent further disease spread.
Access free multiple choice questions on this topic. 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.
H1N1 swine influenza is a common infection in pigs worldwide, and that is why it is also known as swine flu. H1N1 swine flu leads to respiratory disease that can potentially infect the respiratory tract of pigs. Sometimes, people who are closely associated with pigs or in the proximity of pigs have developed swine flu zoonotic swine flu. Swine influenza viruses can potentially cause infections in humans if antigenic characteristics of the virus change through reassortment.
When this happens, transmission from person-to-person is usually inefficient. Influenza A pandemics such as the ones in and can occur if the transmission from person-to-person becomes efficient. However, the H1N1 virus was not zoonotic swine flu because it was not transferred from pigs to humans. Instead, it spread through airborne droplets from human to human, and potentially, through human contact with inanimate objects contaminated with the virus and transferred to the eyes or nose.
This virus caused similar symptoms to those seen in swine, possibly due to reassortment of the viral RNA structure, which allowed human-to-human transfer. Despite the name, an individual cannot acquire swine flu from eating pig products such as bacon, ham, and other pig products. 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:.
The function of hemagglutinin is to cause red blood cells to cluster together, and it attaches the virus to the infected cell.
Neuraminidase helps move the virus particles through the infected cell and assists in budding from host cells. The H1N1 swine influenza viruses can potentially cause infections in humans if antigenic characteristics of the virus change. In , the pandemic which started in Mexico with the H1N1 strain displayed a combination of segments of 4 different influenza viruses quadruple genetic reassortment : pig-origin flu North American avian comprising Due to this coinfection with influenza virus from diverse animal species, the viruses were able to interact, mutate, and form new strains that had variable immunity.
Although it had originated in pigs, it was able to spread from human to human. When the flu spreads from human-to-human, instead of from animals to humans, there can be further mutations, making it harder to treat because people have no natural immunity. 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 are closely associated with pigs have been known to develop an infection, and pigs have also been infected with human flu from these handlers. In the vast majority of cases, cross-species transmission of the virus had remained confined to the specific area and not caused national or global infections in either pigs or humans.
Unfortunately, due to the potential for genetic variation in the swine flu virus, there is always a possibility for cross-species transmission with the influenza viruses to occur. Investigators concluded that the " swine flu" strain, which originated in Mexico, was termed novel H1N1 flu since it was mainly found infecting humans and exhibits 2 main surface antigens, hemagglutinin type 1 and neuraminidase type 1. The 8 RNA strands in novel H1N1 flu have 1 strand from human flu strains, 2 derived from avian bird strains, and 5 that were derived from swine strains.
During the pandemic, the Centers for Disease and Control and Prevention CDC estimated that there were 43 to 89 million cases of swine flu reported during a 1-year span, with deaths in countries worldwide. The deadly influenza pandemic caused by H1N1 influenza virus, infected approximately million people around the world and caused the death of roughly fifty to a hundred million people. The H1N1 variant of swine flu is the progeny of the strain that caused the swine flu pandemic.
Although persisting in pigs, the descendant variants of the virus have also known to infect humans, contributing to the yearly seasonal epidemics of influenza. Direct transmission of the virus from pigs to humans is a rare occurrence, with only 12 documented cases in the United States since The potential retention of influenza virus strains in swine after these strains have disappeared in the human population, essentially make pigs a reservoir where swine influenza viruses could persist, and later emerge to reinfect humans once their immunity to these strains has waned.
More recently in , a mutant strain of H1N1 which caused the global pandemic in , spread across India with over 10, reported cases and deaths. 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. The known incubation period for H1N1 swine flu ranges from 1 to 4 days, with the average around 2 days in most individuals, but some individuals, it may be as long as 7 days.
The contagious period for adults starts about 1 day before symptoms develop and lasts around 5 to 7 days after the person develops symptoms.
The contagious period may be longer in individuals with weakened immune systems and children e. The acute symptoms of uncomplicated infections persist for three to seven days, and the disease is mostly self-limited in healthy individuals, but malaise and cough can persist for up to 2 weeks in some patients. Patients with more severe disease may require hospitalization, and this may increase the time of infection to around 9 to 10 days.
The body's immune reaction to the virus and the interferon response are the causes of the viral syndrome which includes high fever, coryza, and myalgia. Patients with chronic lung diseases, cardiac disease and who are currently pregnant are at higher risk of severe complications such as viral pneumonia, superimposed bacterial pneumonia, hemorrhagic bronchitis, and possibly death.
These complications can potentially develop within 48 hours from the onset of symptoms. The replication of the virus occurs primarily in the upper and lower respiratory tract passages from the time of inoculation and peaks around 48 hours in most patients. The recommended time of isolation of the infected patient is around 5 days. Swine flu causes most symptoms in upper and lower respiratory tracts. Mild cases usually show a few pathologic changes in the respiratory tract, but severe cases can show clear pathologic changes of pneumonia.
The pathological findings associated with swine flu include multifocal destruction and potential desquamation of the pseudo columnar and columnar epithelial cells, and possibly prominent hyperemia and edema in the submucosa.
There may also be thrombus formation at the bronchiolar level. Sometimes, the acute inflammation could be severe and indicated by hemorrhagic tracheobronchitis and desquamative bronchiolitis, which could cause necrosis of the bronchiolar wall. It is caused by a novel strain of the influenza virus called H1N1, which seems to have originated in pigs living in a factory farm in Mexico.
What set swine flu apart from other strains of seasonal flu is that children and younger adults were most likely to be infected.
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