广播电视英语短句 第 272 课：罗得西亚热-2

And experts say it now threatens ten million more animals in new areas including southern Sudan. 专家们说，他现在正在威胁包括苏丹南部的一些新地区的一千多万头动物。

Researchers first developed an experimental vaccine against East Coast fever thirty years ago. 研究院们与30年前第一次开发一种针对罗得西亚热的实验性疫苗。

The vaccine works by a process called "infection and treatment." 这种疫苗由一种叫“感染和治疗”的过程来实施作用。

The animals are infected with whole parasites and treated with antibiotics at the same time. 动物们感染了全部的寄生虫，同时用抗生素进行治疗。

This keeps the disease from developing. 这样能阻止疾病继续发展。