<prompt> H1N1 strain of influenza is responsible for-Avian influenzaBird fluSwine fluNone of the above  <response>: Ans. is c i.e., Swine flu Swine flu, also called swine influenza, or pig influenza, is caused by influenza virus. Incubation period is about 1-3 days and the symptoms of swine flu in humans are similar to most influenza infections, e.g. fever, cough, rhinorrhea, fatigue and headache. Swine flu is most commonly caused by HJNI inflenza A. Other influenza virus causing swine flu, occasionally, are H1N2, H2N1, H3N2 and H2N3. 