Swine Influenza is also called swine flu, hog flu, and pig flu.
Some authorities object to calling the flu outbreak “swine flu”. U.S. Agriculture Secretary Tom Vilsack expressed concerns that this would lead to the misconception that pork is unsafe for consumption. In the Netherlands, it was originally called “pig flu”, but is now called “Mexican flu” by the national health institute and in the media. South Korea and Israel briefly considered calling it the “Mexican virus”. Currently, the South Korean press uses “SI”, short for “swine influenza”. Taiwan suggested the names “H1N1 flu” or “new flu”, which most local media now use. The World Organization for Animal Health has proposed the name “North American influenza”. The European Commission uses the term “novel flu virus”.
The WHO announced they would refer to the new influenza virus as influenza A(H1N1) or “Influenza A (H1N1) virus, human” as opposed to “swine flu”, also to avoid suggestions that eating pork products carried a risk of infection.
The outbreak has also been called the “H1N1 influenza”,”2009 H1N1 flu”, or “swine-origin influenza”. However, Seth Borenstein, writing for the Associated Press quoted several experts who objected to any name change at all.
Transmission of swine influenza virus from pigs to humans is not common and properly cooked pork poses no risk of infection. When transmitted, the virus does not always cause human influenza and often the only sign of infection is the presence of antibodies in the blood, detectable only by laboratory tests. When transmission results in influenza in a human, it is called zoonotic swine flu.
People who work with pigs, especially people with intense exposures, are at risk of catching swine flu. However, only about fifty such transmissions have been recorded since the mid-20th century, when identification of influenza subtypes became possible.
The 2009 flu outbreak in humans, known as “swine flu”, is due to a new strain of influenza A virus subtype H1N1 that contained genes most closely related to swine influenza. The origin of this new strain is unknown. However, the World Organization for Animal Health (OIE) reports that this strain has not been isolated in pigs.This strain can be transmitted from human to human, and causes the normal symptoms of influenza.
Annual influenza epidemics are estimated to affect 5-15% of the world population, resulting in severe illness in 3-5 million patients, and causing 250,000-500,000 deaths worldwide. Severe illness and deaths, especially in industrialized countries, mainly occur in high-risk populations of elderly and chronically ill patients.
Above and beyond the 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 the Influenza A virus that had undergone major genetic changes.
The new strain has spread widely beyond Mexico and the U.S., with confirmed cases in eighteen countries and suspected cases in forty-two. Many countries have advised their inhabitants not to travel to infected areas. Areas including Australia, Hong Kong, Iceland, India, Indonesia, Malaysia, Philippines, Singapore, South Korea and Thailand are monitoring visitors returning from flu-affected areas to identify people with fever and respiratory symptoms. Many countries have also issued warnings to visitors of flu-affected areas to contact a doctor immediately if they had flu-like symptoms.
Mexico’s schools, universities, and all public events were closed from April 24 to May 6, 2009. By May 3, 2009, more than 400 school closures in the U.S., which included entire school districts in Texas, affected 250,000 students due to confirmed or probable cases in students or staff.
Although the current trivalent influenza vaccine is unlikely to provide protection against the new 2009 H1N1 strain, vaccines against the new strain are being developed and could be ready as early as June 2009.
1. What is swine influenza?
Swine influenza (Swine Flu), is a highly contagious acute respiratory disease of pigs, caused by influenza .A virus that regularly causes diseases and outbreaks of influenza in pigs. Swine Flu viruses causes high level of illness (high morbidity) and low death rates (low mortality) at about 1-4 % in pigs. The mode of spreads of this virus among pigs is by aerosols and direct and indirect contact, and asymptomatic carrier pigs exist. Outbreaks in pigs occur throughout the year, with an increased incidence in the fall and winter in temperate zones similar to outbreaks in humans.
2. How many Swine Flu viruses are there?
Swine Flu viruses change constantly as other influenza viruses. Four main influenza A virus subtypes been isolated in pigs. Those viruses are most commonly of the H1N1 subtype, but other subtypes are also circulating in pigs (e.g., H1N2, H3N1, H3N2). Pigs can also be infected with avian influenza viruses and human seasonal influenza viruses as well as swine influenza viruses. The H3N2 swine virus was thought to have been originally introduced into pigs by humans. Sometimes pigs can be infected with more than one virus type at a time, which can allow the genes from these viruses to mix resulting in an influenza virus containing genes from a number of sources. , called a “reassortant” virus. Although swine influenza viruses are normally specific species and only infect pigs, they do sometimes cross the species barrier to cause disease in humans. Most of the recently isolated influenza viruses from pigs have been H1N1 viruses.
3. Where have human cases occurred?
Since the implementation of IHR (2005)1 in 2007, WHO (World Health Organization) has been notified of swine influenza cases from the United States and Spain. As of 24 April 2009, there were 854 cases of severe atypical pneumonia with 59 deaths in Mexico. From 50 samples that have been tested, 17 cases were positive for atypical strain of Swine Flu virus A (H1N1). In the United States, there were 8 cases reported positive for H1N1 but no death so far.
4. What are the signs and symptoms of Swine Flu in people?
The symptoms of Swine Flu in people are similar to the symptoms of regular Human Flu and include chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. Some people have reported diarrhoea and vomiting associated with Swine Flu. In the past, severe illness (pneumonia and respiratory failure) and deaths have been reported with Swine Flu infection in people. Like Seasonal Flu, swine flu may cause a worsening of underlying chronic medical conditions.
5. Is it safe to eat pork and pork products?
Yes. There is no evidence that Swine Flu can be transmitted through eating properly handled and prepared pork (pig meat) or other products derived from pigs. However, it is essential to cook pig meat properly. The swine influenza virus is killed by cooking temperatures of 160°F/70°C, corresponding to the general guidance for the preparation of pork and other meat.
6. How do people become infected?
Swine Flu does not normally infect humans, although sporadic cases do occur. People usually get swine influenza through contact with infected pigs, or environment contaminated with Swine Flu viruses. However, some human cases lack contact history with pigs or environment where pigs have been located. Human-to-human transmission has been documented in some instances but was limited to close contacts and closed groups of people.
7. Is there a human vaccine to protect from swine influenza?
No. Current seasonal influenza vaccine produced based on WHO recommendation does not contain swine influenza virus. It is unknown whether the seasonal vaccines can provide any cross protection to ongoing swine influenza virus infection in the United States and Mexico.
What drugs are available for treatment?
Most of the previously reported swine influenza cases recovered fully from the disease without requiring medical attention and without antiviral medicines.
8. How long can an infected person spread Swine Flu to others?
People with swine influenza virus infection should be considered potentially contagious as long as they are symptomatic and possible for up to 7 days following illness onset. Children, especially younger children, might potentially be contagious for longer periods.
9. What can I do to protect myself from getting sick?
There is no vaccine available right now to protect against Swine Flu. There are certain actions that can help prevent the spread of germs that cause respiratory illnesses like influenza such as:
» Cover your nose and mouth with a disposable tissue or handkerchief when you cough or sneeze. Throw the tissue in the waste basket after you use it.
» Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.
» Try to avoid close contact with sick people.
» If you get sick with influenza, stay at home and limit contact with others to keep from infecting them. Avoid touching your eyes, nose or mouth.
» Consult your nearest health care facilities
On April 29, the Emergency Committee had their third meeting, and decided to raise the pandemic alert level to five, the second-highest level, indicating that a pandemic is “imminent,” and that human-to-human transmission cases have been recorded in multiple countries. In Catalonia, officials confirmed the first European case of an infection in a person who had not (recently) traveled to Mexico, in a person whose girlfriend had done so, the second WHO region to experience intergenerational transmission of this strain of H1N1.
