（请教）血清转化是什么意思？
丁香园论坛
1944
原文
Although some asymptomatic and mild infections have been documented, they seem to be uncommon and do not appear to contribute to the extension of the chain of infection among humans. For example, a recent mild infection with SARS-CoV acquired in the laboratory was not transmitted to any contacts of the affected person. Despite numerous attempts, there has been no documented isolation of the virus from persons with asymptomatic infections, and in recent serologic and epidemiologic studies, transmission from persons with asymptomatic cases to contacts could not be detected.SARS-CoV RNA was detected in four asymptomatic, quarantined persons in Hong Kong, with seroconversion in one, but no virus could be isolated.
译文
尽管有一些无症状或轻度感染者记录在案，这些病例并不常见，也并不造成人类感染链的扩散。比如在实验室内近期轻度SARS-CoV感染后，接触易感人群并不造成任何传播。尽管大量努力尝试过，但仍然没有从无症状感染者分离出的病毒的记载。最近的血清学和流行病学研究没有发现无症状感染者传播疾病给接触者。香港的四名无症状的接受隔离的人士中检测出SARS-CoV RNA，其中一人有血清转化现象，但是每例都没有分离出病毒。
因为翻译的需要，我想知道血清转化的准确、全面定义。
谢谢。
Although some asymptomatic and mild infections have been documented, they seem to be uncommon and do not appear to contribute to the extension of the chain of infection among humans. For example, a recent mild infection with SARS-CoV acquired in the laboratory was not transmitted to any contacts of the affected person. Despite numerous attempts, there has been no documented isolation of the virus from persons with asymptomatic infections, and in recent serologic and epidemiologic studies, transmission from persons with asymptomatic cases to contacts could not be detected.SARS-CoV RNA was detected in four asymptomatic, quarantined persons in Hong Kong, with seroconversion in one, but no virus could be isolated.
译文
尽管有一些无症状或轻度感染者记录在案，这些病例并不常见，也并不造成人类感染链的扩散。比如在实验室内近期轻度SARS-CoV感染后，接触易感人群并不造成任何传播。尽管大量努力尝试过，但仍然没有从无症状感染者分离出的病毒的记载。最近的血清学和流行病学研究没有发现无症状感染者传播疾病给接触者。香港的四名无症状的接受隔离的人士中检测出SARS-CoV RNA，其中一人有血清转化现象，但是每例都没有分离出病毒。
因为翻译的需要，我想知道血清转化的准确、全面定义。
谢谢。
