No one knows what triggered the vomiting syndrome, but stress is often a causative factor - so even that might have been linked to the disorders Darwin gained during the voyage.

没有人知道是什么导致了呕吐综合症，但压力通常是一个诱因-甚至也可能与达尔文在航海旅行中患上的失调症有关联。

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Older children and adults who have whooping cough often appear to have a bad cold or persistent cough that can be so severe that it causes vomiting.

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