RESEARCH SARS TRANSMISSION Table 1. Timing of collection of clinical specimens from seven confirmed SARS case-patients, United States, 2003 No. of specimens (no. of case-patients) by no. of days after illness onset Specimen type 0–14 days 15–28 days >28 days Total no. of specimens Respiratory 11 (7) 12 (4) 18 (7) 41 Sputum 2 (2) 2 (1) 0 (0) 4 NP swab 5 (5) 4 (4) 9 (6) 18 OP swab 2 (2) 6 (4) 9 (7) 17 Nasal aspirate 1 (1) 0 (0) 0 (0) 1 Nasal wash 1 (1) 0 (0) 0 (0) 1 Stool 1 (1) 5 (2) 8 (6) 14 Urine 0 (0) 2 (2) 6 (5) 8 Serum/blood 18 (7) 15 (4) 15 (7) 48 aSARS, severe acute respiratory syndrome; NP, nasopharyngeal; OP, oropharyngeal. case-patients (1 from case-patient 5 and 3 from case- patient 7). SARS-CoV was detected by both RT-PCR and viral culture in the sputum sample of case-patient 5, which was collected at day 14 after illness onset (Figure). All other respiratory specimens, including seven nasopharyn- geal and oropharyngeal swab samples collected during the first 2 weeks of illness from five case-patients, tested neg- ative by RT-PCR. A total of 14 stool specimens were obtained from seven case-patients: two patients provided 4 samples each, one patient had 2 samples, and four had 1 sample each. SARS- CoV RNA was detected in five specimens, all of which came from two case-patients (one specimen from case- patient 6 and four specimens from case-patient 7) (Figure). The single positive stool specimen from case-patient 6 was obtained 19 days after onset; his subsequent stool specimens (collected at days 23, 32, and 44) tested negative for SARS- CoV by RT-PCR. The first stool specimen from case-patient 7 was collected on day 14 of illness; viral RNA was detect- ed in all four of his stools, including the last one, which was collected at day 26. SARS-CoV was not isolated by culture from any of the RT-PCR–positive stool specimens. The highest concentrations of SARS-CoV were detect- ed in sputum from case-patient 5 (43 million copies per gram of specimen) and in the day-14 stool from case- patient 7 (37 million copies per gram of specimen) (Table 2). After day 14 of illness, the concentration of virus in stool specimens from case-patient 7 dropped by 20-fold or more. Of note, this case-patient reported moderate diarrhea from days 2 to 12 of illness. Case-patient 6 had only mild diarrhea during the first 4 days of illness, and the amount of virus in his stool sample that was collected on day 19 (i.e., 2 weeks after the resolution of diarrhea) was approx- imately 800-fold lower than the amount in the day-14 stool sample of case-patient 7 and approximately 50-fold lower than that found in subsequent specimens from case-patient 7. No evidence was found that the virus mutated in case- patient 7 during the infection: genomic sequences of S and N genes of SARS-CoV from all positive stool specimens of this case-patient were identical. No viral RNA was detected by RT-PCR in any of the eight urine specimens collected from the seven case- patients. SARS-CoV antibody was first found as early as days 10 and 11 after illness onset in three of seven case- patients. Adequate specimens were not available to charac- terize the time of first detectable SARS-CoV antibody in the remaining four case-patients (Table 3). Figure. Detecting severe acute respiratory syndrome-associated coronavirus (SARS-CoV) RNA by reverse transcriptase-poly- merase chain reaction (RT-PCR) and SARS-CoV antibodies by enzyme-linked immunosorbent assay (ELISA) in clinical speci- mens from seven confirmed SARS case-patients, United States, 2003. Circle within circle: blood specimens (same symbol repre- sents both whole blood and serum when both specimens are col- lected and results are entirely concordant. s, serum; wb, whole blood (symbols are labeled s or wb if either blood or serum was collected). Blocked symbols denote SARS-CoV-positive speci- mens by ELISA. : respiratory specimens (include np, nasopha- ryngeal swab; nw, nasal wash; a, nasal aspirate; op, oropharyn- geal swab; sp, sputum). : stool. : urine. Blocked symbols denote SARS-CoV-positive specimens by RT-PCR. Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 10, No. 2, February 2004 227