“…This study included sequencing and antigenic analysis of virus isolates from Europe, the USA, South America, Africa and Hong Kong. Equine influenza virus also circulates in mainland China where large epizootics have been reported (Guo et al, 1991(Guo et al, , 1992, but isolates were not available for the present study. Australia and New Zealand also have large horse populations but have so far been free from the disease.…”