Half of the victims have been hospitalised, a high rate that may indicate an especially virulent strain of E. coli.

半数受害者都已住院，如此高的住院率表明这可能是一种毒性特别强的大肠杆菌菌株。

youdao

The authors argue the version of the disease that caused the medieval plague is likely extinct, but suggest that further study could reveal how it may have evolved into a less virulent strain.

作者们称引起中世纪瘟疫的品种可能已经灭绝了，但是他们认为进一步的研究可以揭示它是如何进化到一种没那么致命的类型。

youdao

Before 1997 WNV was not considered pathogenic for birds, but at that time in Israel a more virulent strain caused the death of different bird species presenting signs of encephalitis and paralysis.

在1997年以前，西尼罗河病毒并未被认为对鸟类具有致病性，但就在那时，以色列出现了一种能够导致多种鸟类出现脑炎和麻痹症状继而死亡的毒力更强的毒株。

youdao

It's a virulent strain that occurs when a person with TB fails to complete the six to nine-month course of medication or catches TB from another person who is ill with a drug resistant-strain.

VOA: standard.2010.07.12

No target is too mighty, or too obscure, for this new and virulent strain of oratory.

FORBES: Attack of the Blogs

Half of the victims have been hospitalised, a high rate that may indicate an especially virulent strain of E. coli.

ECONOMIST: Those healthy green leaves cause a terrible scare

They then subdivided the groups and infected the resulting subgroups with either H3N1, a mild strain of influenza, or H1N1, a virulent strain.

ECONOMIST: A new way to protect against infection is undergoing tests