HIV and syphilis in young Chinese adults: implications for spread

Our objective was to explore the epidemiology of HIV and syphilis at population level in young Chinese adults. The study was carried out in six areas of three Chinese provinces: Zhejiang, Yunnan and Shaanxi. All couples attending the compulsory premarital examination were recruited. Routinely taken blood was collected onto filter paper. Tests for HIV and syphilis used modified particle agglutination techniques. In all, 17,226 individuals were tested. There were no HIV infections in Zhejiang or Shaanxi. In Yunnan, there were 28 positives: 0.75% (95% confidence interval: 0.5, 1.1), with 22 (78%) in men and 16 (57%) in known high-risk individuals. Syphilis prevalence ranged from 0.33% to 0.71% across study sites, with 58% in men. Although syphilis levels suggest that unsafe sexual activity is occurring in all areas, HIV is not yet affecting the general population of Zhejiang or Shaanxi. The epidemic in Yunnan is being driven by injecting drug users, but there may now be transmission in the general population.

Design and evaluation of a primer pair that detects both Norwalk- and Sapporo-like caliciviruses by RT-PCR

A primer pair (p289/290) based on the RNA polymerase sequence of 25 prototype and currently circulating strains of human caliciviruses (HuCVs) was designed for the detection of both Norwalk-like caliciviruses (NLVs) and Sapporo-like caliciviruses (SLVs) by reverse transcription-polymerase chain reaction (RT-PCR). This primer pair produces RT-PCR products of 319 bp for NLVs and 331 bp for SLVs. The usefulness of this primer pair was shown by its detection of prototype NLVs (Norwalk, Snow Mountain, Hawaii and Mexico viruses) and SLVs (Sapporo/82, Hou/86, Hou/90 and Lon/92) and currently circulating strains of NLVs and SLVs in children and adults. This primer pair also detected more viruses in either NLV or SLV genera than previously designed primers. This primer pair is useful for broad detection of HuCVs for clinical and epidemiologic studies as well as for environmental monitoring.

Phylogenetic analysis of the Caliciviruses

A phylogenetic portrait of the genus Calicivirus in the family Caliciviridae was developed based upon published sequences and newly characterized calicivirus (CV) strains, including additional Sapporo-like HuCV strains in pediatric diarrhea stool specimens from South Africa, the United Kingdom, and the United States. Distance and parsimony methods were applied to nucleotide and amino acid sequences of human and animal calicivirus 3D RNA-dependent RNA polymerase (approximately 470nt) and capsid hypervariable regions (approximately 1,200nt) to generate phylogenetic trees. Pairwise amino acid identity in the 3D region among the Sapporo-like strains ranged from 61% to 100%. Human and animal caliciviruses (HuCVs and AnCVs) separated into five genogroups: small round-structured viruses (SRSV), Sapporo-like, and hepatitis E virus (HEV)-like HuCVs and rabbit-, and vesicular exanthema of swine virus (VESV)-like AnCVs, each with a distinct genome organization. Each genogroup, including the Sapporo-like HuCVs, subdivided further into subgenogroups. The capsid region trees had higher levels of confidence than the 3D region trees and limited conclusions about genogroups could be drawn from the 3D region analyses. This analysis suggested that CVs include five potential virus subfamilies.