The 2009 outbreak of Influenza A virus subtype H1N1 is an health isue all around the world the people most at risk in australia are air hostes or ground crew members that work at the local airports.the worst place afected in australia is the state of victoria. epidemic of a new strain of influenza virus identified in April 2009, commonly referred to as "swine flu." It is thought to be a mutation ("reassortment") of four known strains of influenza A virus subtype H1N1: one endemic in humans, one endemic in birds, and two endemic in pigs (swine). The source of the outbreak in humans is still unknown, but cases were first discovered in the U.S. and soon after in Mexico, which had a surge of cases, many of them fatal. As a result, the U.N.'s World Health Organization (WHO), along with the U.S. Centers for Disease Control and Prevention (CDC), expressed concern that this could become a worldwide flu pandemic, with WHO raising its alert level to "Phase 5" out of the six maximum, indicating that a pandemic was "imminent."
According to the CDC, it is not yet clear how serious this new virus actually is compared with other influenza viruses, although on May 26th they stated that new cases in the U.S. have probably peaked, and most cases throughout the world have so far been mild relative to "seasonal flus." But because this is a new virus, most people will not have immunity to it, and illness may eventually become more severe and widespread in different demographic and population groups as a result. The H1N1 flu mainly spreads in the same way that regular "seasonal influenza" spreads, which is through the air from coughs and sneezes or touching those infected. It cannot be transmitted from eating cooked pork or by being in close contact with pigs.
As yet there is no vaccine available to prevent infection although companies are in the planning stages for having one available later this year. But there is concern that the virus could mutate again over the coming months, leading to a new and potentially more dangerous flu outbreak later in the year, and a vaccine that will be less effective in preventing its spread. Health officials in the U.S. point out that the "horrific" 1918 flu pandemic, which killed 20 million people in the United States alone, was preceded by a mild "herald" wave of cases in the spring.
As of May 27, the virus had spread to more than 50 countries; however, over 80% of reported deaths have taken place in Mexico. This has led to speculation that Mexico may have been in the midst of an unrecognized epidemic for many months prior to the current outbreak. According to the CDC, the fact that the flu's infection activity is now monitored more closely may help explain why more flu cases than normal are being recorded in Mexico, the United States and other countries. About half of all influenza viruses being detected so far are the new H1N1 virus, which "experts acknowledge is no worse than seasonal influenza for now."
Historical context
Annual influenza epidemics are estimated to affect 5–15% of the global population, resulting in severe illness in 3–5 million patients and causing 250,000–500,000 deaths worldwide. In industrialized countries severe illness and deaths occur mainly in the high-risk populations of infants, the elderly, and chronically ill patients.
In addition to these annual epidemics, the influenza A virus caused three major global pandemics during the 20th century: the Spanish flu in 1918, Asian flu in 1957 and Hong Kong flu in 1968–69. These pandemics were caused by an Influenza A virus that had undergone major genetic changes and for which the population did not possess significant immunity.
The influenza virus has also caused several pandemic threats over the past century, including the pseudo-pandemic of 1947, the 1976 swine flu outbreak and the 1977 Russian flu, all caused by the H1N1 subtype. The world has been at an increased level of alert since the SARS epidemic in Southeast Asia (caused by the SARS coronavirus). The level of preparedness was further increased and sustained with the advent of the H5N1 bird flu outbreaks because of H5N1's high fatality rate, although the strains currently prevalent have limited human-to-human transmission (anthroponotic) capability, or epidemicity.
People who contracted flu prior to 1957 may have some immunity. A May 20th New York Times article stated: “Tests on blood serum from older people showed that they had antibodies that attacked the new virus, Dr. Daniel Jernigan, chief flu epidemiologist at the Centers for Disease Control and Prevention, said in a telephone news conference. That does not mean that everyone over 52 is immune, since some Americans and Mexicans older than that have died of the new flu.
Initial outbreaksAccording to the CDC, it is not yet clear how serious this new virus actually is compared with other influenza viruses, although on May 26th they stated that new cases in the U.S. have probably peaked, and most cases throughout the world have so far been mild relative to "seasonal flus." But because this is a new virus, most people will not have immunity to it, and illness may eventually become more severe and widespread in different demographic and population groups as a result. The H1N1 flu mainly spreads in the same way that regular "seasonal influenza" spreads, which is through the air from coughs and sneezes or touching those infected. It cannot be transmitted from eating cooked pork or by being in close contact with pigs.
As yet there is no vaccine available to prevent infection although companies are in the planning stages for having one available later this year. But there is concern that the virus could mutate again over the coming months, leading to a new and potentially more dangerous flu outbreak later in the year, and a vaccine that will be less effective in preventing its spread. Health officials in the U.S. point out that the "horrific" 1918 flu pandemic, which killed 20 million people in the United States alone, was preceded by a mild "herald" wave of cases in the spring.
As of May 27, the virus had spread to more than 50 countries; however, over 80% of reported deaths have taken place in Mexico. This has led to speculation that Mexico may have been in the midst of an unrecognized epidemic for many months prior to the current outbreak. According to the CDC, the fact that the flu's infection activity is now monitored more closely may help explain why more flu cases than normal are being recorded in Mexico, the United States and other countries. About half of all influenza viruses being detected so far are the new H1N1 virus, which "experts acknowledge is no worse than seasonal influenza for now."
Historical context
Annual influenza epidemics are estimated to affect 5–15% of the global population, resulting in severe illness in 3–5 million patients and causing 250,000–500,000 deaths worldwide. In industrialized countries severe illness and deaths occur mainly in the high-risk populations of infants, the elderly, and chronically ill patients.
In addition to these annual epidemics, the influenza A virus caused three major global pandemics during the 20th century: the Spanish flu in 1918, Asian flu in 1957 and Hong Kong flu in 1968–69. These pandemics were caused by an Influenza A virus that had undergone major genetic changes and for which the population did not possess significant immunity.
The influenza virus has also caused several pandemic threats over the past century, including the pseudo-pandemic of 1947, the 1976 swine flu outbreak and the 1977 Russian flu, all caused by the H1N1 subtype. The world has been at an increased level of alert since the SARS epidemic in Southeast Asia (caused by the SARS coronavirus). The level of preparedness was further increased and sustained with the advent of the H5N1 bird flu outbreaks because of H5N1's high fatality rate, although the strains currently prevalent have limited human-to-human transmission (anthroponotic) capability, or epidemicity.
People who contracted flu prior to 1957 may have some immunity. A May 20th New York Times article stated: “Tests on blood serum from older people showed that they had antibodies that attacked the new virus, Dr. Daniel Jernigan, chief flu epidemiologist at the Centers for Disease Control and Prevention, said in a telephone news conference. That does not mean that everyone over 52 is immune, since some Americans and Mexicans older than that have died of the new flu.
U.S.
Both the place and the species in which the virus originated are unknown. Analysis has suggested that the H1N1 strain responsible for the current outbreak first evolved around September 2008 and circulated in the human population for several months before the first cases were detected. The new strain was first diagnosed in two children by the CDC, first on April 14 in San Diego County, California and a few days later in nearby Imperial County, California. Neither child had been in contact with pigs.
Mexico
Further information: 2009 swine flu outbreak in Mexico
The outbreak was first detected in Mexico City, where surveillance began picking up a surge in cases of influenza-like illness starting March 18th. The surge was initially assumed by Mexican authorities to be "late-season flu" outbreak and not a new virus strain. After samples were sent to the CDC in mid-April, however, the Mexican cases were confirmed by the CDC and the World Health Organization to be a new strain of H1N1. Although Mexican news media had speculated that the outbreak may have started at a pig plant that engaged in intensive farming practices, to date, no pigs in Mexico have tested positive for the virus and investigators have found no swine influenza at any of the pig farms.
Current SituationThe outbreak was first detected in Mexico City, where surveillance began picking up a surge in cases of influenza-like illness starting March 18th. The surge was initially assumed by Mexican authorities to be "late-season flu" outbreak and not a new virus strain. After samples were sent to the CDC in mid-April, however, the Mexican cases were confirmed by the CDC and the World Health Organization to be a new strain of H1N1. Although Mexican news media had speculated that the outbreak may have started at a pig plant that engaged in intensive farming practices, to date, no pigs in Mexico have tested positive for the virus and investigators have found no swine influenza at any of the pig farms.
United Kingdom
"Confirmed cases of swine flu in the UK have leapt by 47 to 184 after an outbreak at a school. The Department of Health said yesterday that 44 of the new cases were linked to the school in the West Midlands." 44 hit by swine flu outbreak at school, The Herald (Scotland), May 26, 2009.
North America
Associated Press, May 26, 2009: "Authorities in Mexico announced three more swine flu deaths and the United States and Canada one more death each"
Although each death is of course a tragedy, this is not an exponential increase.
Mexico, US, Canada announce swine flu deaths
May 26, 2009.
United States
New York
Associated Press, May 26th: "New York City's health commissioner says two more deaths have been linked to swine flu. Dr. Thomas Frieden said Tuesday that a 41-year-old woman from Queens and a 34-year-old man from Brooklyn have died. That's a total of four in the city since the outbreak started last month. Twenty city schools reopened Tuesday, a week after an assistant principal at an intermediate school became the city's first victim of swine flu, or the H1N1 virus."
2 more deaths in NYC are linked to swine flu, Associated Press, VERENA DOBNIK, May 26, 2009.Houston
Houston Chronicle, May 22nd: "The Heights school — the site of the single largest swine flu outbreak in Texas with 27 confirmed cases — closed May 15. It was slated to re-open after Memorial Day, but state and local officials agreed Friday afternoon that the school should remain closed past the last day of school on Thursday."
Flu closes Travis Elementary for rest of school year, Houston Chronicle, JENNIFER RADCLIFFE and TODD ACKERMAN, May 22, 2009.
Flu closes Travis Elementary for rest of school year, Houston Chronicle, JENNIFER RADCLIFFE and TODD ACKERMAN, May 22, 2009.
Asia Pacific Region
Examiner, May 26th: "Elsewhere in the Asia-Pacific region, Japan has 334 confirmed swine flu cases, China 11, South Korea 21, Australia 16, Taiwan six, India one, and New Zealand nine."
Philippines confirms second swine flu case, Examiner, Susan Cunningham, May 26, 2009.
Philippines confirms second swine flu case, Examiner, Susan Cunningham, May 26, 2009.
Japan
Japan Times, May 25:"The tally of swine flu infections in Japan rose to 342 on Sunday, as four more people, including a 19-year-old man in Toyono, Osaka Prefecture, and an 18-year-old male high school student in Nishinomiya, Hyogo Prefecture, were confirmed as having the new H1N1 virus. Osaka and Hyogo prefectures, where more than 310 of the confirmed patients live, plan to allow elementary, junior high and high schools to resume classes Monday after they were shut down for about a week."
Four new flu cases; schools to reopen, Japan Times, Kyodo News, May 25, 2009.
Four new flu cases; schools to reopen, Japan Times, Kyodo News, May 25, 2009.
Australia
Bloomberg May 26th: "Australia has 39 confirmed cases of swine flu, the nation’s government said. Cases have been confirmed in six of the nation’s eight states and territories, with 23 confirmed in southern Victoria."
News.com.au May 27th: "At least 50 cases of A(H1N1) virus have been confirmed in Australia, and more are expected."
News.com.au May 27th: "At least 50 cases of A(H1N1) virus have been confirmed in Australia, and more are expected."
BBC May 27: “The number of swine flu cases in Australia has doubled in the last day to 59. The government warned that the virus, spreading fast, has been confirmed in most Australian states and territories. Health experts have said its rapid transmission was coinciding with the southern hemisphere's traditional winter flu season.”Australia swine flu cases double,Phil Mercer, BBC News, Sydney 04:22 GMT, Wednesday, 27 May 2009.
ABC News, May 26: “The hospital clinics will mean staff can separate people with the flu from other patients in emergency departments. Under the new measures, some nurses will be able to administer the anti-viral drug Tamiflu. . . . The Federal Health Minister Nicola Roxon says that number will rise significantly over the next few days. Ms Roxon says while the flu is very infectious, it has so far proved to be fairly mild in Australia.” Swine flu clinics to open at public hospitals, ABC News, May 26, 2009.
ANNE KELSO, director of the WHO Collaborating Centre for Influenza in Melbourne, May 25th/26th: “We certainly are concerned about that because as the conditions become more suitable for the spread of flu in winter here, then if there is wide-spread circulation of this virus then inevitably it will mutate. What we won't know of course, until it happens is whether those mutations will make the virus worse or better so that we simply have to wait and see.” Swine flu containment critical, ABC Online, interview with Tony Eastley reported on May 26, 2009.
ABC News, May 26: “The hospital clinics will mean staff can separate people with the flu from other patients in emergency departments. Under the new measures, some nurses will be able to administer the anti-viral drug Tamiflu. . . . The Federal Health Minister Nicola Roxon says that number will rise significantly over the next few days. Ms Roxon says while the flu is very infectious, it has so far proved to be fairly mild in Australia.” Swine flu clinics to open at public hospitals, ABC News, May 26, 2009.
ANNE KELSO, director of the WHO Collaborating Centre for Influenza in Melbourne, May 25th/26th: “We certainly are concerned about that because as the conditions become more suitable for the spread of flu in winter here, then if there is wide-spread circulation of this virus then inevitably it will mutate. What we won't know of course, until it happens is whether those mutations will make the virus worse or better so that we simply have to wait and see.” Swine flu containment critical, ABC Online, interview with Tony Eastley reported on May 26, 2009.
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