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

卫生专家考虑这归咎于一种毒力更强的新菌种.

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Objective To analyse HP and its condition of virulent strain infection in recruited flying students.

目的分析应招飞行学员幽门螺杆菌(HP) 及其有毒株感染状况.

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