The success of the program to eradicate smallpox has stimulated experts to pursue something they had not previously considered possible-better control, if not eradication, of such infections as measles and yaws. 消灭天花过程的成功促使专家追捕一些他们过去从来没有考虑的传染病比如M和Y。是这个意思吗,中间的better control,if not eradication是用来说明什么的了