The head of the WHO is warning that a few cases of the novel coronavirus that have been spread by people who never traveled to China could bethe tip of the iceberg as officials reported the highest single-day death toll since . WHO Director-General said the "spread outside #China appears to be slow, but could accelerate."世衛秘書長：中國境外武漢肺炎確診例數可能是冰山一角 | 國際 | 中央社 CNA