The disease spreads widely and quickly.

这种疾病传播广并且速度快。

Experts say foot - and - mouth disease spreads quickly unless it is discovered early and stopped immediately.

专家们说,除非病毒很早被发现并且马上制止,否则口蹄疫传播极快.

One question the researchers will try to answer is how the disease spreads from one part of the brain to another.

另一个研究者试图去回答的问题就是此病如何在大脑中传播。

A pandemic can only be declared when the disease spreads easily, /it affects many different age groups, /and there is no concrete cure at the time of spreading.

大流行疾病只有当这种病很容易传播，/它影响许多不同的年龄组，/而且在传播时还没有具体的治疗方法时会被宣告。