What is 2009 H1N1 (swine flu)?

What is 2009 H1N1 (swine flu)?

2009 H1N1 (referred to as “swine flu” early on) is a new influenza virus causing illness in people. This new virus was first detected in people in the United States in April 2009. This virus is spreading from person-to-person worldwide, probably in much the same way that regular seasonal influenza viruses spread. On June 11, 2009, the World Health Organization(WHO) signaled that a pandemic of 2009 H1N1 flu was underway.
Why is 2009 H1N1 virus sometimes called “swine flu”?This virus was originally referred to as “swine flu” because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine) in North America. But further study has shown that this new virus is very different from what normally circulates in North American pigs. It has two genes from flu viruses that normally circulate in pigs in Europe and Asia and bird (avian) genes and human genes. Scientists call this a "quadruple reassortant" virus.

___________________

Bibliography; CDC

What is the new influenza A(H1N1)?

What is the new influenza A(H1N1)?
This is a new influenza A(H1N1) virus that has never before circulated among humans. This virus is not related to previous or current human seasonal influenza viruses.

How do people become infected with the virus?
The virus is spread from person-to-person. It is transmitted as easily as the normal seasonal flu and can be passed to other people by exposure to infected droplets expelled by coughing or sneezing that can be inhaled, or that can contaminate hands or surfaces.To prevent spread, people who are ill should cover their mouth and nose when coughing or sneezing, stay home when they are unwell, clean their hands regularly, and keep some distance from healthy people, as much as possible. There are no known instances of people getting infected by exposure to pigs or other animals. The place of origin of the virus is unknown.

What are the signs and symptoms of infection?
Signs of influenza A(H1N1) are flu-like, including fever, cough, headache, muscle and joint pain, sore throat and runny nose, and sometimes vomiting and diarrhoea.

Why are we so worried about this flu when hundreds of thousands die every year from seasonal epidemics?
Seasonal influenza occurs every year and the viruses change each year - but many people have some immunity to the circulating virus which helps limit infections. Some countries also use seasonal influenza vaccines to reduce illness and deaths. But influenza A(H1N1) is a new virus and one to which most people have no or little immunity and, therefore, this virus could cause more infections than are seen with seasonal flu. WHO is working closely with manufacturers to expedite the development of a safe and effective vaccine but it will be some months before it is available. The new influenza A(H1N1) appears to be as contagious as seasonal influenza, and is spreading fast particularly among young people (from ages 10 to 45). The severity of the disease ranges from very mild symptoms to severe illnesses that can result in death. The majority of people who contract the virus experience the milder disease and recover without antiviral treatment or medical care. Of the more serious cases, more than half of hospitalized people had underlying health conditions or weak immune systems.

Most people experience mild illness and recover at home. When should someone seek medical care?
A person should seek medical care if they experience shortness of breath or difficulty breathing, or if a fever continues more than three days. For parents with a young child who is ill, seek medical care if a child has fast or labored breathing, continuing fever or convulsions (seizures). Supportive care at home - resting, drinking plenty of fluids and using a pain reliever for aches - is adequate for recovery in most cases. (A non-aspirin pain reliever should be used by children and young adults because of the risk of Reye's syndrome.)

What is the difference between the new influenza A(H1N1)v and swine influenza?

¿What is the difference between the new influenza A(H1N1) and swine influenza?
The typical swine influenza (swine flu) is an acute viral infection of the respiratory tract in pigs, caused by type A influenza virus. The mortality rate is low in pigs and recovery usually occurs within 7–10 days. Swine-origin influenza infections also occur in wild birds, poultry, horses and humans, but transmission between species is considered a rare event. So far three influenza type A virus subtypes have been found in pigs: H1N1, H1N2 and H3N2.
Zoonotic human infections with swine influenza viruses have been detected occasionally since the late 1950s, usually in persons with direct exposure to pigs (e.g. people working on pig farms, etc.). In Europe, since 1958 a total of 17 cases have been reported. In the US in 1976, an outbreak of swine influenza virus infections in humans was detected among recruits in a military camp in Fort Dix, New Jersey. A link to pigs was presumed but never established. Instead there was limited human-to-human transmission, with over 200 infections resulting in 12 hospitalisations and one death. In contrast to the swine influenza virus, the new influenza A(H1N1)v virus is capable of human-to-human transmission.

______________

ECDC.Frequently asked questions oninfluenza A(H1N1)v virus

Un bueen Ejemplo de cómo caracterizar Epidemiológicamente la Influenza AH1N1

Les invito a leer el presente reporte contentivos de información de la Epidemia de Influenza AH1N1 en España. Resulta interesante por brindar valiosa informacion obtenida mediante el analisis epidemiologico.

Dr. Héctor Parra L

Eurosurveillance.Vol 14.Issue 19.April-May 2009

New Influenza A(H1N1) Virus infections in Spain.April-May 2009