Health experts are worried that a new, more virulent strain may be to blame.

卫生专家担心这一现象归咎于一种毒力更强的新菌种。

youdao

It remains to be seen whether the virus will mutate into a more virulent strain.

该病毒是否会产生变异，成为毒性更强的病毒株，仍有等观察。

youdao

Conclusion The infection of virulent strain of mouse poxvirus exists in experimental mice.

结论实验用昆明小鼠中存在鼠痘病毒强毒株感染。

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