Prevalence of human (H1N1) influenza virus-antibody in japanese swine

A total of 571 swine sera collected at an abattoir in the city of Obihiro, Hokkaido during the period February-November 1984 were tested for antibody against human (H1N1) influenza virus strains. A high prevalence of antibody was observed for only 3 months from April to June in that year, in 81/180 sera (45.0%) to A/USSR/92/77 strain and in 50/180 sera (27.8%) to a current epidemic strain (A/Hokkaido/1/84). Some cross-reactions were observed...