<prompt> At present following types of influenza viruses are circulating in the world, except-H1N1H3N2H5N1B virus  <response>: At present three types of influenza viruses are circulating in the world : A H1N1, A H3N2 and B virus. WHO global surveillance activities have identified human infection with a new influenza viruse called A H5N1 in Hong Kong in mid 1997. However, the possibility that the outbreak heralded a global influenza pandemics did not materialize. Ref: PARK;S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE , 23rd edition , Page :153 