Swine influenza is an infection caused by any of several types of swine influenza viruses. Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) refers to any strain of the influenza family of viruses that is endemic in pigs. As of 2009, identified SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3.
In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus. Major outbreaks of H1N1 strains in humans include the Spanish flu, the 1977 Russian flu pandemic and the 2009 swine flu pandemic. It is an orthomyxovirus that contains the glycoproteins hemagglutinin and neuraminidase. For this reason, they are described as H1N1, H1N2 etc., depending on the type of H or N antigens they express with metabolic synergy. Hemagglutinin causes red blood cells to clump together and binds the virus to the infected cell. Neuraminidase is a type of glycoside hydrolase enzyme which helps to move the virus particles through the infected cell and assist in budding from the host cells.
The 2009 swine flu pandemic, caused by the H1N1 influenza virus and declared by the World Health Organization (WHO) from June 2009 to August 2010, is the third recent flu pandemic involving the H1N1 virus. The first two cases were discovered independently in the United States in April 2009. The virus appeared to be a new strain of H1N1 that resulted from a previous triple reassortment of bird, swine, and human flu viruses which further combined with a Eurasian pig flu virus, leading to the term "swine flu".
The 2009 flu pandemic in the United States was caused by a novel strain of the Influenza A/H1N1 virus, commonly referred to as "swine flu", that was first detected on 15 April 2009. While the 2009 H1N1 virus strain was commonly referred to as "swine flu", there is no evidence that it is endemic to pigs or of transmission from pigs to people; instead, the virus spreads from person to person. On April 25, the World Health Organization declared a public health emergency, followed concurringly by the Obama administration on April 26.
The 2009 swine flu pandemic in Canada was part of an epidemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu. In Canada, roughly 10% of the populace has been infected with the virus, with 428 confirmed deaths ; non-fatal individual cases are for the most part no longer being recorded. About 40% of Canadians have been immunized against H1N1 since a national vaccination campaign began in October 2009, with Canada among the countries in the world leading in the percentage of the population that has been vaccinated. The widespread effect of H1N1 in Canada raised concerns during the months leading to the XXI Olympic Winter Games, which took place in Vancouver in February 2010.
This article covers the chronology of the 2009 novel influenza A (H1N1) pandemic. Flag icons denote the first announcements of confirmed cases by the respective nation-states, their first deaths, and relevant sessions and announcements of the World Health Organization (WHO), the European Union , and the U.S. Centers for Disease Control (CDC).
The 2009 flu pandemic was a global outbreak of a new strain of influenza A virus subtype H1N1, first identified in April 2009, termed Pandemic H1N1/09 virus by the World Health Organization (WHO) and colloquially called swine flu. The outbreak was first observed in Mexico, and quickly spread globally. On 11 June 2009, the WHO declared the outbreak to be a pandemic. The overwhelming majority of patients experienced mild symptoms, but some persons were in higher risk groups, such as those with asthma, diabetes, obesity, heart disease, who were pregnant or had a weakened immune system. In the rare severe cases, around 3–5 days after symptoms manifest, the sufferer's condition declines quickly, often to the point of respiratory failure.
Australia had 37,537 confirmed cases of H1N1 Influenza 2009 and 191 deaths reported by Department of Health but only 77 deaths reported by the Australian Bureau of Statistics. The actual numbers are much larger, as only serious cases warranted being tested and treated at the time. Suspected cases have not been reported by the Department of Health and Ageing since 18 May 2009 because they were changing too quickly to report. Sources say that as many as 1600 Australians may have actually died as a result of this virus. On 23 May 2009 the federal government classified the outbreak as CONTAIN phase except in Victoria where it was escalated to the SUSTAIN phase on 3 June 2009. This gave government authorities permission to close schools in order to slow the spread of the disease. On 17 June 2009 the Department of Health and Ageing introduced a new phase called PROTECT. This modified the response to focus on people with high risk of complications from the disease. Testing at airports was discontinued. The national stockpile of antiviral drugs were no longer made available to people with the flu unless there were more than mild symptoms or a high risk of dying.
This article deals with the status and efforts regarding the 2009 swine flu pandemic by country and continent/region.
In reaction to the 2009 flu pandemic, governments around the world have responded with sometimes extreme reactions against pigs, which has included the official extermination of all domestic pigs in Egypt and the culling of three wild boars at the Baghdad Zoo in Iraq. Many of these slaughters occurred in Muslim countries, and religious restrictions on the consumption of pork have been cited as influencing the decision to take such action. Many other countries have banned international trade in pigs and pork products.
The pandemic H1N1/09 virus is a swine origin influenza A virus subtype H1N1 strain that was responsible for the 2009 swine flu pandemic. This strain is often called swine flu by the public media. For other names, see the Nomenclature section below.
The 2009 flu pandemic in South America was part of a global epidemic in 2009 of a new strain of influenza A virus subtype H1N1, causing what has been commonly called swine flu. As of 9 June 2009, the virus had affected at least 2,000 people in South America, with at least 4 confirmed deaths. On 3 May 2009, the first case of the flu in South America was confirmed in a Colombian man who recently travelled from Mexico – since then, it has spread throughout the continent. By far, the most affected country has been Chile, with more than 12,000 confirmed cases, 104 deaths, and the highest per capita incidence in the world.
The 2009 flu pandemic in Asia, part of an epidemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu, afflicted at least 394,133 people in Asia with 2,137 confirmed deaths: there were 1,035 deaths confirmed in India, 737 deaths in China, 415 deaths in Turkey, 192 deaths in Thailand, and 170 deaths in South Korea. Among the Asian countries, South Korea had the most confirmed cases, followed by China, Hong Kong, and Thailand.
The 2009 swine flu pandemic in North America, part of a pandemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu, began in the United States or Mexico.
The 2009 flu pandemic in Oceania, part of an epidemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu, has afflicted at over 22,000 people in Oceania, with 56 confirmed deaths. Almost all of the cases in Oceania have been in Australia, where the majority of cases have resulted from internal community spread of the virus. In addition, the government of New Zealand, where most of the remainder of cases in Oceania have occurred, is on high alert for any people travelling into the country with flu-like symptoms.
The 2009 flu pandemic in Europe was part of a pandemic involving a new strain of influenza, subtype H1N1. H1N1 is commonly called swine flu. The pandemic infected at least 125,550 people in Europe. There were 458 confirmed deaths in Turkey, 438 confirmed deaths in Russia, and 457 confirmed deaths in the United Kingdom.
The United States experienced the beginnings of a pandemic of a novel strain of the influenza A/H1N1 virus, commonly referred to as "swine flu", in the spring of 2009. The earliest reported cases in the US began appearing in late March 2009 in California, then spreading to infect people in Texas, New York, and other states by mid-April. Early cases were associated with recent travel to Mexico; many were students who had traveled to Mexico for Spring Break. This spread continued across the country's population and by the end of May there were approximately 0 confirmed cases throughout all 50 states.
The 2009 swine flu pandemic in New Zealand was caused by a novel strain of the A/H1N1 influenza virus. A total of 3,175 cases and 19 deaths were recorded, although a seroprevalence study estimated that around 800,000 individuals may have been infected during the initial wave of the pandemic.
2009 flu pandemic in India was the outbreak of swine flu in various parts of India. Soon after the outbreak of H1N1 virus in the United States and Mexico in March, the Government of India started screening people coming from the affected countries at airports for swine flu symptoms. The first case of the flu in India was found on the Hyderabad airport on 13 May, when a man traveling from US to India was found H1N1 positive. Subsequently, more confirmed cases were reported and as the rate of transmission of the flu increased in the beginning of August, with the first death due to swine flu in India in Pune, panic began to spread. As of 24 May 2010, 10193 cases of swine flu have been confirmed with 1035 deaths.
The 2009 flu pandemic was a global outbreak of a new strain of influenza A virus subtype H1N1, first identified in April 2009, termed Pandemic H1N1/09 virus by the World Health Organization (WHO) and colloquially called swine flu. The outbreak was first observed in Mexico, and quickly spread globally. On 11 June 2009, WHO declared the outbreak to be a pandemic. The overwhelming majority of patients experience mild symptoms", but some persons are in higher risk groups, such as those with asthma, diabetes, obesity, heart disease, or who are pregnant or have a weakened immune system. In the rare severe cases, around 3–5 days after symptoms manifest, the person's condition declines quickly, often to the point respiratory failure.
