But a number of experts have doubted this assertion。 They said it is likely that infections happened mostly before the imposition of the quarantine。 

　　正如專家指出，工作人員也可能是病毒深度滲透的原因之一，因為他們接觸到大量可能感染病毒的乘客，一旦工作人員感染了病毒，他們很容易成為病毒的傳播者。

　　世界衛(wèi)生組織前西太平洋地區(qū)主任尾身茂指出，船上工作人員沒有像乘客一樣接受隔離，他們“同吃同住，這是隔離開始后一些人感染病毒的原因”。

　　就“鉆石公主”號上病毒傳播速度快，世界衛(wèi)生組織衛(wèi)生緊急項目主管邁克爾·瑞安解釋，“有時候疾病在一些環(huán)境中就是能更快速傳播，比如郵輪。”

　　他表示，相信日本政府以及接回本國公民的其他國家政府“有能力以恰當(dāng)方式繼續(xù)跟進這些人”的健康狀況。

　　尾身茂說，病毒傳播早期，隔離是有效抑制傳播的措施。他建議，隨著病毒逐步進入日本社區(qū)，日本政府應(yīng)當(dāng)把重點從邊境管控轉(zhuǎn)移至阻止病毒在社區(qū)內(nèi)傳播。

　　As experts endeavor to find an alternative explanation to account for the failure of virus prevention， they turn the focus onto quarantine measures。 

　　While the Japanese government has repeatedly defended the effectiveness of the quarantine， some suggest it may have been less than rigorous。 Three Japanese health officials who helped conduct the quarantine checks on the ship were also infected， indicating a possible sign of lax protocols。 

　　“There are sometimes environments in which disease can spread in a more efficient way，” said Dr。 Michael Ryan， executive director of the World Health Organization‘s health emergency program。 Ryan said cruise ships， in particular， were known to occasionally accelerate spread。