There is no difference in the illness caused by the two serogroups.

两种血清性引起的疾病症状没有区别。

There are many serogroups of V. cholerae, but only two – O1 and O139 – cause outbreaks.

霍乱弧菌有许多血清型，但只有O1和O139两种血清型会引起霍乱暴发。

The Centers for Disease Control and Prevention (CDC) issued a warning on March 28 about the increase in one kind of invasive " meningococcal disease" called serogroup Y.

美国疾病控制和预防中心(CDC)于3月28日发布警告，称一种名为Y群的侵袭性“脑膜炎球菌病”数量有所增加。