On our conjecture, Gene 3A, a highly conserved sequence, may be the determinant of the virulence of FMDV. Changes in 3A have been associated with altered host range.

• 我们根据已有资料推测，3A基因可能是口蹄疫病毒的毒力决定簇，它具有高度保守性，其变异和部分缺失对病毒在牛体内的致弱和宿主嗜性发生改变起重要作用。