2009 Swine flu is due to:

Option 1: The 2009 flu pandemic or swine flu was an influenza pandemic caused by H1N1 and the second of the two pandemics involving H1N1 influenza virus (the first was the 1918 for pandemic.) H1N1 2009 Flu: Staed in April 2009. Pandemic - affected the whole world including India. It is made by reassoment of 4 strains (1 Human + 2 Swine + 1 An Strain) in pigs. Human to human transmission seen - hence more infectious. H1N1 was less virulent (as it lacks PB1F2 protein gene) compared to H5N1 therefore it had more morbidity but less moality. Diagnosis - by PCR detecting Hemagglutinin and Neuraminidase genes. Option 2: H5N1 : An influenza or bird flu. Option 3: H2N2: 1957 pandemic ("Asian Flu"). Option 4: H3N2: 1968 pandemic