H1N1 2009 in Karachi: A situational analysis

The novel H1N1 influenza A, also known as Swine Flu, first emerged in Mexico in March 2009, when the Government of Mexico reported increasing cases of Influenza-Like Illness (ILI). By April, more than 854 cases of pneumonia with 59 deaths were recorded. On the 24th of April 2009, the United States Government reported seven human cases of what was thought to be Swine Influenza in California. Twelve of the 18 laboratory confirmed Mexican cases were found to be genetically identical to this virus, which emerged as a consequence of a series of viral coinfections in pigs leading to gene reassortment between human, avian and two strains of swine influenza A viruses. As opposed to the seasonal H1N1, this novel influenza virus was unique not only in the continent of origin (North America, not Asia), the season of origin (spring, not late fall), but also the cohort at risk for infection and death (children and young adults, not infants and the elderly).