H5N1 is a strain of:

Ans. is 'a' i.e., Avian flu (Ref: Park, 22nd/e, p. 145)* At present three types of influenza viruses are circulating in the world: A(H1 N1 ),A(H3 N2 ), and B viruses.* WHO global surveillance activities have identified human infection with a new influenza virus called A(H5 N1 ),in Hong Kong in mid 1997. However, the possibility that the outbreak heralded a global influenza pandemic did not materialize and it is transmitted to man only from birds, requires close respiratory contact.