Important facts about swine flu

What is swine flu?regular exposure to pigs are at increased risk of
Swine influenza (also called H1N1 flu, swine flu, hog flu,swine flu infection. People who work with poultry and
and pig flu) is an infection by any one of severalswine, especially people with intense exposures, are
types of swine influenza virus. Swine influenza virus isat increased risk of zoonotic infection with influenza
common throughout pig populations worldwide. Swinevirus endemic in these animals, and constitute a
influenza virus (SIV) is any strain of the influenzapopulation of human hosts in which zoonosis and
family of viruses.reassortment can co-occur. Vaccination of these
How many types of flu viruses are there?workers against influenza and surveillance for new
          Of the three genera of influenzainfluenza strains among this population may therefore
viruses that cause human flu, two also causebe an important public health measure. Other
influenza in pigs, with influenza A being common inprofessions at particular risk of infection are
pigs and influenza C being rare. Influenza B has notveterinarians and meat processing workers, although
been reported in pigs. Swine influenza is known to bethe risk of infection for both of these groups is
caused by influenza A subtypes H1N1, H1N2, H3N1,lower than that of farm workers
H3N2 and H2N3. In pigs, three influenza A virus 
subtypes (H1N1, H3N2, and H1N2) are the mostSigns & Symptoms
common strains worldwideSymptoms of zoonotic swine flu in humans are similar
 to those of influenza and of influenza-like illness in
HISTORYgeneral, namely chills, fever, sore throat, muscle
Swine influenza was first proposed to be a diseasepains, severe headache, coughing, weakness and
related to human influenza during the 1918 flugeneral discomfort. The strains of swine flu rarely
pandemic, when pigs became sick at the same timepass from human to human. The 2009 H1N1 virus is
as humans. The first identification of an influenza virusnot zoonotic swine flu, as it is not transmitted from
as a cause of disease in pigs occurred about tenpigs to humans, but from person to person.
years later, in 1930.           The most common cause of death
 is respiratory failure, other causes of death are
1918 pandemic in humanspneumonia (leading to sepsis); high fever (leading to
The 1918 flu pandemic in humans was associatedneurological problems), dehydration (from excessive
with H1N1 and influenza appearing in pigs; this mayvomiting and diarrhea) and electrolyte imbalance.
reflect a zoonosis either from swine to humans, orFatalities are more likely in young children and the
from humans to swine. Although it is not certain inelderly.
which direction the virus was transferred, somePrevention of human to human transmission
evidence suggests that, in this case, pigs caught theInfluenza spreads between humans through coughing
disease from humans.or sneezing and people touching something with the
1976 U.S. outbreakvirus on it and then touching their own nose or
This new strain appeared to be closely related to themouth Swine flu cannot be spread by pork products,
strain involved in the 1918 flu pandemic. Moreover,since the virus is not transmitted through food. The
the ensuing increased surveillance uncovered anotherswine flu in humans is most contagious during the
strain in circulation in the U.S.: A/Victoria/75 (H3N2)first five days of the illness although some people,
spread simultaneously, also caused illness, andmost commonly children, can remain contagious for
persisted until March. On October 1, 1976, theup to ten days
immunization program began and by October 11,       Recommendations to prevent spread of
approximately 40 million people, or about 24% of thethe virus among humans include using standard
population, had received swine flu immunizations.infection control against influenza. This includes
 frequent washing of hands with soap and water or
1988 zoonosiswith alcohol-based hand sanitizers, especially after
In September 1988, a swine flu virus killed onebeing out in public. Chance of transmission is also
woman and infected others. Influenza-like illness (ILI)reduced by disinfecting household surfaces, which can
was reportedly widespread among the pigs However,be done effectively with a diluted chlorine bleach
there was no community outbreak.solution
1998 US outbreak in swineSocial distancing is another tactic. It means staying
In 1998, swine flu was found in pigs in four U.S.away from other people who might be infected and
states. Within a year, it had spread through pigcan include avoiding large gatherings
populations across the United States. Scientists foundVaccines are available for different kinds of Swine Flu.
that this virus had originated in pigs as a recombinantThe blue surgical masks you've seen being passed
form of flu strains from birds and humans.out to Mexican pedestrians are better than nothing
2007 Philippine outbreak in swinebut probably only marginally useful, said Andrew
On August 20, 2007 Department of AgriculturePekosz, associate professor of microbiology and
officers investigated the outbreak of swine flu inimmunology at the Johns Hopkins Bloomberg School
Philippines. The mortality rate is less than 10% forof Public Health in Baltimore, Maryland.
swine flu, unless there are complications like hogWhile such masks block the relatively large,
cholera.virus-carrying droplets sneezed out by infected
2009 outbreak in humanspeople, the viruses themselves are much smaller and
The H1N1 viral strain implicated in the 2009 flucould easily pass through. Specialty masks, designated
pandemic among humans often is called "swine flu"N-95 or N-99, are better filters but still not perfect.
because initial testing showed many of the genes inFor better protection, Pekosz recommends combining
the virus were similar to influenza viruses. But furthera mask with regular hand washing and keeping 3 to 4
research has shown that the outbreak is due to afeet (90 to 120 centimeters) away from other
new strain of H1N1 not previously reported in pigs.people
 The WHO's pandemic alert level has been raised a
Transmissionnotch to level 4. Level 5 is considered a pandemic -
          Transmission of the virus from pigs towith "sustained community-level transmission" in at
humans is not common and does not always lead toleast two countries - and level 6 a full-scale global
human influenza. If transmission does cause humanpandemic affecting more than one region in the
influenza, it is called zoonotic swine flu. People withworld.