Tree shrews (Tupaia belangeri chinenesis) can be experimentally infected with human hepatitis B virus (HBV) by inoculation with human serum positive for HBV, the experimental infection rate being 55.21%. Successive infections have been passed through five generations among the tree shrews inoculated with HBV-positive sera from the infected animals, the average infection rate being 94.0%. The experimental infection of tree shrews with HBV may be prevented by immunization with hepatitis B vaccine, the protection rate being 88.89%. Standard serum containing HBV at 10(8) CID (chimpanzee infection dose)/ml, was diluted 10(-6), 10(-7), 10(-8), 10(-9), and 10(-10) and produced infection rates of 80.0%, 88.8%, 66.7%, 55.6% and 42.9% respectively. Thus the CID50 in tree shrews may reach a dilution of 10(-9), which shows that tree shrews are sensitive to HBV infection. These results successfully establish tree shrews as a reliable and useful animal model for research on HBV infection and its relation to hepatocarcinogenesis.

BackgroundThe reported coverage of the measles–rubella (MR) or measles–mumps–rubella (MMR) vaccine is greater than 99.0% in Zhejiang province. However, the incidence of measles, mumps, and rubella remains high. In this study, we assessed MMR seropositivity and disease distribution by age on the basis of the current vaccination program, wherein the first dose of MR is administered at 8 months and the second dose of MMR is administered at 18–24 months.MethodsCross-sectional serological surveys of MMR antibodies were conducted by collecting epidemiological data in Zhejiang province, China in 2011. In total, 1015 participants were randomly selected from two surveillance sites. Serum MMR-specific immunoglobulin G levels were tested by enzyme-linked immunosorbent assay. The geometric mean titers and seroprevalence with 95% confidence intervals (CIs) were calculated by age and gender. Proportions of different dose of vaccine by age by vaccine were also identified. Statistically significant differences between categories were assessed by the Chi-square test.ResultsOver 95% seroprevalence rates of measles were seen in all age groups except <7 months infants. Children aged 5–9 years were shown lower seropositivity rates of mumps while elder adolescences and young adults were presented lower rubella seroprevalence. Especially, rubella seropositivity was significantly lower in female adults than in male. Nine measles cases were unvaccinated or unknown vaccination history. Among them, 66.67% (6/9) patients were aged 20–29 years while 33.33% (3/9) were infants aged 8–12 months. In addition, 57.75% (648/1122) patients with mumps were children aged 5–9 years, and 50.54% (94/186) rubella cases were aged 15–39 years.ConclusionsA timely two-dose MMR vaccination schedule is recommended, with the first dose at 8 months and the second dose at 18–24 months. An MR vaccination speed-up campaign may be necessary for elder adolescents and young adults, particularly young females.

ObjectivesTo investigate the associations between body mass index (BMI), waist-to-hip ratio (WHR) and cognitive function among Chinese elderly.DesignCross-sectional study.SettingCommunity.ParticipantsData were obtained from the baseline survey of a community-based cohort in Zhejiang Province, and 9326 persons aged 60 years and older were enrolled.Primary outcome measuresWe investigated the association between BMI and cognition, and then explored the association between WHR and cognition across different quartiles of BMI.ResultsA sample of 9087 persons was used in this study, including 4375 men and 4712 women. Higher WHR increased cognitive impairment risk in those with BMI >25.3 kg/m2 (OR (per 0.1 increase) 1.39; 95% CI 1.13 to 1.70). No statistically significant association was found in other BMI categories.ConclusionsHigher WHR could increase the risk of cognitive impairment among elderly with BMI >25.3 kg/m2. Our results suggest that it could be of benefit to the elderly with high BMI to control WHR.

On the basis of the successful establishment of an animal model in tree shrews experimentally infected with human hepatitis B virus (HBV), a study on the hepatocarcinogenic effects of HBV and/or aflatoxin B1 (AFB1) was conducted. The results showed that the incidence of hepatocellular carcinoma (HCC) was significantly higher in the animals both infected with HBV and exposed to AFB1 (52.94%) than in those solely infected with HBV (11.11%) or exposed to AFB1 (12.50%). No HCC of precancerous lesions were found in the controls that were neither HBV-infected nor AFB-1 exposed. Precancerous lesions, including liver cell dysplasia and enzyme-altered hyperplastic hepatocyte foci, were observed before the occurrence of HCC, and the frequency of their appearance correlated well with the incidence of HCC. HBV DNA and the protein it encodes were detected in the cancer cells and/or the surrounding hepatocytes. Integration of HBV DNA into the host liver genome was found during hepatocarcinogenesis among the animals infected by HBV. These results suggest that exposure to HBV and AFB1 may play a synergistic role in the development of HCC, and support the viewpoint of an aetiological relationship between HBV and HCC.

Objective Cancer survivors (CSs) often face the dual physical burden of cancer and other comorbid chronic disease (CCD) and have a great deal of psychological distress, such as anxiety and depression. However, the association between CCD and psychological problems remain less clear in CS. This study was performed to investigate the prevalence of anxiety and depression in Chinese CS, and whether CCD have impact on CSs' anxiety and depression. Methods A cross‐sectional study was conducted among 1546 CSs in Shanghai, China. All participants were asked to complete a questionnaire containing Zung self‐rating anxiety scale (SAS), Zung self‐rating depression scale (SDS), and questions on sociodemographic characteristics and CCD. Associations between CCDs, and anxiety and depression, were evaluated by using logistic regression, adjusted for confounding factors. Results The prevalence of anxiety and depression in CSs were 28.2 % and 48.2%, respectively. 74.9% CSs had one or more comorbidities. Almost all CCDs examined showed associations with anxiety, except for CSs with diabetes. CSs with hyperlipidemia, diabetes, heart and cardiovascular diseases, and musculoskeletal diseases had significantly greater depression scores. When compared with those without CCD, CSs with one to two CCDs and greater than or equal to three CCDs had higher risks of anxiety and depression. Conclusions Anxiety and depression were more prevalent among CSs who also had CCDs. CCD have significantly negative association with CSs' anxiety and depression. Further cohort research will help deduce the causal relationships between CCDs, and anxiety and depression.

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ObjectivesThis investigation was undertaken in response to an outbreak of suspected shellfish poisoning in Zhejiang Province, China. The objectives of this project were to confirm the outbreak and to identify the aetiology, source and mode of transmission.MethodsA probable case was defined as an individual with diarrhea (≥3 times/day) plus at least one of the following symptoms: fever (≥37.5°C), vomiting, or abdominal pain after consuming seafood between May 23rd and May 28th, 2011. Using a case-control study design, we compared exposures to suspected seafood items and cooking methods between 61 probable cases and 61 controls.ResultsOver 220 suspected or probable cases of diarrhetic shellfish poisoning (DSP) were identified (incidence of 18 cases per 100,000). The case control study revealed that 100% of cases and 18% of controls had eaten mussels during the exposure period (OR = ∞, χ2 = 84.72,P = 0.000). The number of mussels consumed was related to DSP risk (P = 0.004, χ2 test for trend). Consumption of other seafood items was not associated with disease. The frequency of diarrhea and vomiting were positively correlated with the number of mussels consumed (r = 0.424 and r = 0.562, respectively). The frequency of vomiting and the incubation period were significantly correlated with the total time the mussels were boiled (r = 0.594 and r = −0.336, respectively). Mussels from 3 food markets and one family contained Okadaic acid (OA) and Dinophysistoxin-1 (DTX-1).ConclusionsThis outbreak was attributed to the consumption of mussels contaminated by DSP-toxins (OA and DTX-1) which are produced by different species of dinoflagellates (toxic microalgae) from the genus Dinophysis or Prorocentrum. Suspension of mussel sales and early public announcements were highly effective in controlling the outbreak, although oversight of seafood quality should be a priority to prevent future contamination and outbreaks.