 
 <translate> To answer this question, we should know that: The 1918 flu pandemic (January 1918 -- December 1920) was an unusually deadly influenza pandemic, the first of the two pandemics involving H1N1 influenza virus. The answer is H1N1 influenza virus. <ibo> Iji zaa ajụjụ a, anyị kwesịrị ịma nke a: Ọrịa influenza nke 1918 (January 1918 - December 1920) bụ ọrịa influenza nke gburu ọtụtụ mmadụ n'ụzọ pụrụ iche, nke mbụ n'ime ọrịa abụọ ahụ metụtara nje influenza H1N1. Azịza ya bụ nje influenza H1N1. 