MEMS biosensor for detection of Hepatitis A and C viruses in serum.

Resonant microcantilever arrays are developed for the purpose of label-free and real-time analyte monitoring and biomolecule detection. MEMS cantilevers made of electroplated nickel are functionalized with Hepatitis antibodies. Hepatitis A and C antigens at different concentrations are introduced in undiluted bovine serum. All preparation and measurement steps are carried out in the liquid within a specifically designed flowcell without ever drying the cantilevers throughout the experiment. Both actuation and sensing are done remotely and therefore the MEMS cantilevers have no electrical connections, allowing for easily disposable sensor chips. Actuation is achieved using an electromagnet and the interferometric optical sensing is achieved using laser illumination and embedded diffraction gratings at the tip of each cantilever. Resonant frequency of the cantilevers in dynamic motion is monitored using a self-sustaining closed-loop control circuit and a frequency counter. Specificity is demonstrated by detecting both Hepatitis A and Hepatitis C antigens and their negative controls. This is the first report of Hepatitis antigen detection by resonant cantilevers exposed to undiluted serum. A dynamic range in excess of 1000 and with a minimum detectable concentration limit of 0.1ng/ml (1.66pM) is achieved for both Hepatitis A and C. This result is comparable to labeled detection methods such as ELISA.

The role of injection versus socioeconomic factors in hepatitis A virus infection among young heroin users: Implications for vaccination policies.

The aim of this study was to determine whether heroin users have a higher prevalence of HAV infection than the general population in Spain, and whether injection is an independent risk factor. A cross-sectional cohort study was conducted between April 2001 and December 2003 in Spain that included 953 current heroin users aged 18-30 years. Dried blood spot samples were tested for HAV by ELISA. The prevalence of HAV infection (35.5%) was higher than in the general population of the same age. The logistic regression analysis did not show association between HAV infection and injection. HAV infection was associated with low educational level (OR=4.8; 95% CI=2.1-10.9) and other low-income variables. Injection is not an independent risk factor for HAV infection; rather, the principal determinants are socioeconomic factors. Consequently, HAV vaccination should be recommended not only in IDUs but also in non-IDUs depending on their socioeconomic characteristics.

Hepatitis A, B, and C infection in a community of sub-Saharan immigrants living in Verona (Italy).

BACKGROUND: In Italy, about 5% of the population is represented by immigrants. The epidemiology of hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection in Africa is very different from Europe; the present study aimed to assess the seroprevalence of viral hepatitis infections in sub-Saharan African immigrants living in Verona. METHODS: A total of 182 illegal immigrants were interviewed concerning sociodemographic characteristics and epidemiological information. Their serum was tested for anti-HAV [immunoglobulin (Ig) G and IgM], HBV (HBsAg, anti-HBs, anti-HBc, HBeAg, and anti-HBe), and HCV (anti-HCV) markers. RESULTS: The immigrants (age: 3 mo-60 y) were mostly single and males, with a higher education; only 50% of them declared having a regular job. Anti-IgG HAV+ prevalence was 99.5% (100% HAV positivity in the younger age bracket). As for HBV, 67.6% (123) of the immigrants were naturally infected and 9.3% had chronic infection; 4.4% were anti-HBs+ isolated (vaccinated). For HBV infection (any HBV marker), a significant difference was only found for increasing age ( p < 0.01) and married people ( p < 0.001). A statistically significant prevalence of HBsAg was found among the unemployed ( p < 0.001) and those with a lower education ( p < 0.05). Five cases (2.7%) resulted in HCV+ with no reported specific risk factors and with no significantly different sociodemographic features; these people tended to report a low level of education and unemployment. CONCLUSIONS: HAV and HBV positivity is higher than in the autochthonous population. While HAV positivity merely represents past infection, the high prevalence of HBsAg in immigrants and the presence of HBsAg/HBeAg in the same group may represent a risk for HBV transmission. The HCV positivity rate resulted similar to the prevalence of the Italian population.

Clinical and virological improvement of hepatitis B virus-related or hepatitis C virus-related chronic hepatitis with concomitant hepatitis A virus infection.

BACKGROUND: We evaluated the clinical and virological characteristics of hepatitis A virus infection in persons concomitantly infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). METHODS: We enrolled 21 patients with acute hepatitis A and chronic hepatitis with no sign of liver cirrhosis, 13 patients who were positive for hepatitis B surface antigen (case B group), 8 patients who were anti-HCV positive (case C group), and 21 patients with acute hepatitis A without a preexisting liver disease (control A group). Two control groups of patients with chronic hepatitis B (control B group) or C (control C group) were also chosen. All control groups were pair-matched by age and sex with the corresponding case group. RESULTS: Fulminant hepatitis A was never observed, and hepatitis A had a severe course in 1 patient in the case B group and in 1 patient in the control A group. Both patients recovered. On admission, HBV DNA was detected in 1 patient in the case B group (7.7%) and in 13 patients (50%) in the control B group; HCV RNA was found in no patient in the case C group and in 16 patients (81.2%) in the control C group. Of 9 patients in the case B group who were followed up for 6 months, 3 became negative for hepatitis B surface antigen and positive for hepatitis B surface antibody, 2 remained positive for hepatitis B surface antigen and negative for HBV DNA, and 4 became positive for HBV DNA with a low viral load [corrected] Of 6 patients in the case C group who were followed up for 6 months, 3 remained negative for HCV RNA, and 3 had persistently low viral loads. CONCLUSION: Concomitant hepatitis A was always self-limited, associated with a marked inhibition of HBV and HCV genomes, and possibly had a good prognosis for the underlying chronic hepatitis.

Seroepidemiological markers of enterically transmitted viral hepatitis A and E in individuals living in a community located in the North Area of Rio de Janeiro, RJ, Brazil.

We investigated the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) infection in subjects living in the community of Manguinhos, Rio de Janeiro, Brazil, and assisted at the Health Unit of Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz. After formal consent, individuals were submitted to an interview using a standardized questionnaire. Anti-HAV and anti-HEV antibodies were detected by ELISA. Statistical analysis was carried out using the Epi-Info 6.04b software, to investigate possible associations between serological markers and risk factors. Results were regarded as significant when p value < 0.05. Although a high prevalence of anti-HAV was observed (87%), almost 50% of subjects under the age of 10 were susceptible to HAV infection, an unexpected rate in endemic areas. This fact could be attributed to improvements in environmental sanitation, occurring in this area in the last years. The increasing proportion of susceptible people may result in outbreaks of HAV infection, since the virus still circulates in this area, as verified by the detection of anti-HAV IgM in some individuals. No statistical association was met between HAV infection and the risk factors here assessed. The anti-HEV IgG prevalence found in this population was 2.4%, consistent with the one found in non-endemic areas.