Epidemiological serosurvey of hepatitis B virus among children aged 1-14 years in Guangdong Province, China.

OBJECTIVE: A cross-sectional community prevalence survey was conducted to investigate the sero-epidemiological features of hepatitis B virus (HBV) infection among children aged 1-14 years in Guangdong Province in 2013, and to provide baseline data for the evaluation of HBV disease burden and the impacts of HBV control. METHODS: A total of 2765 children aged 1-14 years from 16 villages/streets of eight cities in Guangdong Province were recruited as subjects. A blood sample was obtained from each subject. A chemiluminescence microparticle immunoassay (CMIA) was used to detect hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (HBsAb), and antibody to hepatitis B core antigen (HBcAb). RESULTS: The prevalence rates of HBsAg, HBsAb, and HBcAb among children aged 1-14 years were 1.16%, 61.63%, and 2.35%, respectively. The prevalence of HBsAg and HBcAb increased with increasing age, and the prevalence was lowest in the 1-4 years age group (0.97% for HBsAg and 1.45% for HBcAb). In contrast, the prevalence of HBsAb decreased with increasing age; however the prevalence was also highest in the 1-4 years age group (76.48%). Eastern Guangdong had the highest prevalence of HBsAg and HBcAb, and the lowest prevalence of HBsAb. The prevalence of HBsAg was under 1% in the Pearl River Delta and western Guangdong regions. Children who had received three or more doses of vaccine had a lower prevalence of HBsAg and HBcAb and a higher prevalence of HBsAb compared to those who had received fewer than three doses of vaccine. CONCLUSIONS: The prevalence of HBsAg among children aged 1-14 years in Guangdong in 2013 was 1.2%, showing a dramatic decrease compared to the 1992 provincial-level cross-sectional survey (19.9%). Children aged 1-4 years and children from the Pearl River Delta had the lowest prevalence of HBsAg positivity. High vaccination coverage among children and timely vaccination of newborns has played an important role in reducing the prevalence of HBsAg.

Isolation and functional analysis of the promoter of the amphioxus Hsp70a gene.

Amphioxus is a promising laboratorial model animal for studying the evolutionary and developmental mechanisms that appeared during the invertebrate-chordate to vertebrate transition. However, the main drawback for the use of amphioxus as a model organism is the lack of well-developed technical approaches. Conditional gene expression, as performed with thermal control, is a very useful strategy in gene function studies. To make this method possible in amphioxus studies, here we report the isolation and characterization of an amphioxus Hsp70 gene (Hsp70a) and its promoter in Chinese amphioxus (Branchiostoma belcheri). Hsp70a showed very low expression at normal temperatures but was robustly induced in animals upon heat shock. The basal cis-acting elements (CAAT and TATA), as well as four heat shock elements (HSEs), were found within the regulatory region (-1031 to -11 upstream from the start codon), but surprisingly most of the elements were located in the 5'UTR region (-252 to -10). Reporter constructs, including sequences from both the transcription start site (TSS) and ATG were tested for transient expression in EPC cells and microinjected zebrafish embryos. Results suggested that the 5'UTR region, which includes a TATA box at -92bp, a CAAT box at -152bp, and three HSE elements (-212 to -106), represents the core hsp promoter sequence of the B. belcheri Hsp70a gene. Therefore in this study we identified an effectively thermo-inducible promoter in amphioxus that could be used for the establishment of a conditional gene expression system in which the target gene can be regulated in a temporal- or tissue-specific way in amphioxus.