They were not caused by the hepatitis viruses that typically cause the illness.

它们不是由通常导致这种疾病的肝炎病毒引起的。

A PCR test begins by collecting a sample: this can be blood for hepatitis viruses, feces for poliovirus, and samples from the nose or throat for coronaviruses.

PCR 测试从采集样本开始： 这可以是肝炎病毒的血液、脊髓灰质炎病毒的粪便以及冠状病毒的鼻子或喉咙样本。