[Quantitative detection of SARS-CoV RNA in excreta and oropharyngeal washing fluid from convalescence patients with severe acute respiratory syndrome].

OBJECTIVE: To detect the severe acute respiratory syndrome coronavirus (SARS-CoV) RNA in excreta and oropharyngeal washing fluid (OWF) from the convalescence SARS patients, and to determine whether convalescence patients carry the SARS-CoV, and whether having infectivity.

METHODS: Totally 531 samples (including urine, stool, and OWF) were collected from 177 convalescence patients with positive SARS antibody which were confirmed by ELISA method. Real-time quantitative PCR was performed to detect the RNA of the SARS-CoV, and results were analyzed by SPSS analysis software.

RESULTS: There were 49 (27.7%) cases of SARS-CoV RNA detection positive in 177 patients, including 31 (17.5%) cases with one sample positive, 14 (7.9%) cases with two samples positive, and 4 (2.3%) cases with three samples positive. The positive rates of urine, stool, and OWF were 14.7% (26/177), 11.9% (21/177), and 13.6% (24/177), respectively. The quantity of SARS-CoV RNA in samples was 100-47 000 copies/ml. No significant difference was found among urine, stool, and OWF on the difference grade quantity of SARS-CoV RNA quantity.

CONCLUSIONS: About 10% convalescence SARS patients might still carry the SARS-CoV in hospitalization. The detection of SARS-CoV RNA by real-time quantitative PCR may become a laboratory examination warranty for convalescence SARS patients to discharge hospital and relieve separation.