Gripe A (H1N1)
The 2009 flu pandemic is a global outbreak of a new strain of an influenza A virus subtype H1N1, referred to as the "novel H1N1" first identified in April 2009, and commonly called "swine flu." It is thought to be a reassortment of four known strains of influenza A virus.
The outbreak began in Mexico, with evidence that Mexico was already in the midst of an epidemic for months before the outbreak was recognized. Soon after, its government closed down most of Mexico City's public and private offices and facilities to help contain the spread. In early June, as the virus spread globally, the World Health Organization (WHO) declared the outbreak to be a pandemic, but also noted that most illnesses were of moderate severity.
In an attempt to slow the spread of the illness, a number of countries, especially in Asia, have quarantined airline passengers with flu symptoms, while some are also pre-screening passengers. WHO does not expect to have a full vaccine before the end of 2009, and vaccines available sooner may be limited and given first to healthcare workers, pregnant women, and other higher risk groups. Two or three injections will be required for maximum immunity from both the swine flu and seasonal flu. There is also concern if the new virus mutates further, it could become more virulent and less susceptible to any new vaccine.
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Credits: wikipedia