ABSTRACT
<p><b>OBJECTIVE</b>To investigate the prevalence of newly identified single-chain DNA virus (SENV) infection in Shenzhen.</p><p><b>METHODS</b>Nested polymerase chain reaction (nPCR) was established using primers from ORF1 region of SENV genome. Six hundred and one sera samples from different populations were detected for SENV DNA (D and H subtype) by nPCR. Products of PCR were cloned into T-vector and sequenced.</p><p><b>RESULTS</b>The positive rates of SENV DNA in different populations were as followed: 27.8% in patients with hepatitis B, 22.2% in patients with hepatitis C, 26.9% in hemodialysis patients and 39.3% in IDUs. Among blood donors, the positive rates of SENV DNA were 28.1% in unqualified blood donors, 31.3% in blood donors with an elevated ALT levels and 15.1% in qualified blood donors. The infection rates of SENV in unqualified blood donors and blood donors with an elevated ALT levels were obviously higher than in qualified blood donors (chi(2) = 8.29, P < 0.01 and chi(2) = 6.03, P < 0.01). There was a 6.8% difference of nucleotide between SENV-D standard subtype and 6 isolates with 13.5% difference of nucleotide between SENV-H standard subtype and 4 isolates from Shenzhen.</p><p><b>CONCLUSION</b>Results suggested that SENV infection was common in high-risk groups in Shenzhen.</p>