Transmission of swine influenza virus from pigs to humans is not common. When transmitted, it does not always cause human influenza and often, the only sign of infection is the presence of antibodies which are only detectable 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 20Century, when identification of influenza subtypes became possible.
The 2009 flu outbreak in humans that is widely known as "swine flu" is due to an apparently virulent new strain of influenza A virus subtype H1N1 that was produced by reassortment from one strain of human influenza virus, one strain of avian influenza virus, and two separate strains of swine influenza. The origin of this new strain is unknown, and the World Organization for Animal Health (OIE) reports that this strain has not been isolated in pigs. It passes with apparent ease from human to human, an ability attributed to an as-yet unidentified mutation. This 2009 H1N1 strain causes the normal symptoms of influenza, such as fever, coughing and headache.
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. 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. 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.
Transmission to humans usually does not result in influenza in humans. When it does result in influenza, usually the influenza is mild and the basic reproduction number of the virus in human hosts is low enough that an outbreak does not occur.
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this is the info from http://en.wikipedia.org/wiki/Swine_influenza
1 comment:
Swine flu become new public enemies no 1. but is it real a new kind of desease? some fact said that there's something wrong with how this new desease appear..
SWINE FLU : IS IT A CONSPIRACY?
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