ARTICLE 5: SWINE FLU LATEST Introduction : Swine influenza (also called H1N1 flu, swine flu, hog flu, and pig flu) is an infection by any one of several types of swine influenza virus. Swine influenza virus (SIV) is any strain of the influenza family of viruses that is endemic in pigs.[2] As of 2009, the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2, and H2N3. History: Swine influenza was first proposed to be a disease related to human influenza during the 1918 flu pandemic, when pigs became sick at the same time as humans.[16] The first identification of an influenza virus as a cause of disease in pigs occurred about ten years later, in 1930.[17] For the following 60 years, swine influenza strains were almost exclusively H1N1. Then, between 1997 and 2002, new strains of three different subtypes and five different genotypes emerged as causes of influenza among pigs in North America. In 1997-1998, H3N2 strains emerged. These strains, which include genes derived by reassortment from human, swine and avian viruses, have become a major cause of swine influenza in North America. Reassortment between H1N1 and H3N2 produced H1N2. In 1999 in Canada, a strain of H4N6 crossed the species barrier from birds to pigs, but was contained on a single farm.[17] The H1N1 form of swine flu is one of the descendants of the strain that caused the 1918 flu pandemic.[18][19] As well as persisting in pigs, the descendants of the 1918 virus have also circulated in humans through the 20th century, contributing to the normal seasonal epidemics of influenza.[19] However, direct transmission from pigs to humans is rare, with only 12 cases in the U.S. since 2005.[20] Nevertheless, the retention of influenza strains in pigs after these strains have disappeared from the human population might make pigs a reservoir where influenza viruses could persist, later emerging to reinfect humans once human immunity to these strains has waned.[21]
Transmission: Transmission between pigs Influenza is quite common in pigs, with about half of breeding pigs having been exposed to the virus in the US.[51] Antibodies to the virus are also common in pigs in other countries.[51] The main route of transmission is through direct contact between infected and uninfected animals.[11] These close contacts are particularly common during animal transport. Intensive farming may also increase the risk of transmission, as the pigs are raised in very close proximity to each other.[52][53] The direct transfer of the virus probably occurs either by pigs touching noses, or through dried mucus. Airborne transmission through the aerosols produced by pigs coughing or sneezing are also an important means of infection.[11] The virus usually spreads quickly through a herd, infecting all the pigs within just a few days.[2] Transmission may also occur through wild animals, such as wild boar, which can spread the disease between farms.[ Transmission to humans: People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur.[55] Vaccination of these workers against influenza and surveillance for new influenza strains among this population may therefore be an important public health measure.[56] Transmission of influenza from swine to humans who work with swine was documented in a small surveillance study performed in 2004 at the University of Iowa.[57] This study among others forms the basis of a recommendation that people whose jobs involve handling poultry and swine be the focus of increased public health surveillance.[55] Other professions at particular risk of infection are veterinarians and meat processing workers, although the risk of infection for both of these groups is lower than that of farm workers.[ Main symptoms of swine flu in swine: These H5N1 infections may be quite common: in a survey of 10 apparently healthy pigs housed near poultry farms in West Java, where avian flu had broken out, five of the pig samples contained the H5N1 virus. The Indonesian government has since found similar results in the same region. Additional tests of 150 pigs outside the area were negative.[63][64] Signs and symptoms: In swine In pigs influenza infection produces fever, lethargy, sneezing, coughing, difficulty breathing and decreased appetite.[11] In some cases the infection can cause abortion. Although mortality is usually low (around 1-4%),[2] the virus can produce weight loss and poor growth, causing economic loss to farmers. Infected pigs can lose up to 12 pounds of body weight over a 3 to 4 week period The H1N1 viral strain implicated in the 2009 flu pandemic among humans often is called "swine flu" because initial testing showed many of the genes in the virus were similar to influenza viruses normally occurring in North American swine.[43] But further research has shown that the outbreak is due to a new strain of H1N1 not previously reported in pigs. The most common cause of death is respiratory failure, other causes of death are pneumonia (leading to sepsis)[69], high fever (leading to neurological problems), dehydration (from excessive vomiting and diarrhea) and electrolyte imbalance. Fatalities are more likely in young children and the elderly. Diagnosis: Different medical kits are available for diagnosis of Swine Flu Prevention in humans: Prevention of pig to human transmission Swine can be infected by both avian and human influenza strains of influenza, and therefore are hosts where the antigenic shifts can occur that create new influenza strains. The transmission from swine to human is believed to occur mainly in swine farms where farmers are in close contact with live pigs. Although strains of swine influenza are usually not able to infect humans this may occasionally happen, so farmers and veterinarians are encouraged to use a face mask when dealing with infected animals. The use of vaccines on swine to prevent their infection is a major method of limiting swine to human transmission. Risk factors that may contribute to swine-to-human transmission include smoking and not wearing gloves when working with sick animals.[ Prevention of human to human transmission Influenza spreads between humans through coughing or sneezing and people touching something with the virus on it and then touching their own nose or mouth.[77] Swine flu cannot be spread by pork products, since the virus is not transmitted through food.[77] The swine flu in humans is most contagious during the first five days of the illness although some people, most commonly children, can remain contagious for up to ten days. Diagnosis can be made by sending a specimen, collected during the first five days for analysis.[ Recommendations to prevent spread of the virus among humans include using standard infection control against influenza. This includes frequent washing of hands with soap and water or with alcohol-based hand sanitizers, especially after being out in public.[79] Chance of transmission is also reduced by disinfecting household surfaces, which can be done effectively with a diluted chlorine bleach solution.[80] Experts agree that hand-washing can help prevent viral infections, including ordinary influenza and the swine flu virus. Influenza can spread in coughs or sneezes, but an increasing body of evidence shows small droplets containing the virus can linger on tabletops, telephones and other surfaces and be transferred via the fingers to the mouth, nose or eyes. Alcohol-based gel or foam hand sanitizers work well to destroy viruses and bacteria. Anyone with flu-like symptoms such as a sudden fever, cough or muscle aches should stay away from work or public transportation and should contact a doctor for advice. Social distancing is another tactic. It means staying away from other people who might be infected and can include avoiding large gatherings, spreading out a little at work, or perhaps staying home and lying low if an infection is spreading in a community. Public health and other responsible authorities have action plans which may request or require social distancing actions depending on the severity of the outbreak. Vaccination: Vaccines are available for different kinds of Swine Flu. Although the current trivalent influenza vaccine is unlikely to provide protection against the new 2009 H1N1 strain,[81] vaccines against the new strain are being developed and could be ready as early as November 2009.[82] Treatment: In swine As swine influenza is rarely fatal to pigs, little treatment beyond rest and supportive care is required.[51] Instead veterinary efforts are focused on preventing the spread of the virus throughout the farm, or to other farms.[11] Vaccination and animal management techniques are most important in these efforts. Antibiotics are also used to treat this disease, which although they have no effect against the influenza virus, do help prevent bacterial pneumonia and other secondary infections in influenza-weakened herds.[51] In humans If a person becomes sick with swine flu, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). Beside antivirals, supportive care at home or in hospital, focuses on controlling fevers, relieving pain and maintaining fluid balance, as well as identifying and treating any secondary infections or other medical problems. The U.S. Centers for Disease Control and Prevention recommends the use of Tamiflu (oseltamivir) or Relenza (zanamivir) for the treatment and/or prevention of infection with swine influenza viruses; however, the majority of people infected with the virus make a full recovery without requiring medical attention or antiviral drugs.[83] The virus isolates in the 2009 outbreak have been found resistant to amantadine and rimantadine. dr. jitender aggarwal ceo sarthak educational trust To unsubscribe send a message to [email protected] with the subject unsubscribe. 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