Prevalence of antibody to hepatitis B virus in an urban population of northeast Brazil

A sample of 1,288 inhabitants of Salvador, Bahia, Brazil, were submitted to the determination of anti-HBs using radioimmunoassay procedure, and analysed according to age, sex and income. Overall prevalence of anti-HBs was 11,8%. ranging from 6,7% among children aged less than three years old to 26,1% among those aged 30 years and older. Males presented prevalence of anti-HBs similar to female individuals, and those with a higher income showed frequencies of anti-HBs greater than those with a lower income level. The following conclusions were drawn: The high prevalence of anti-HBs observed among children suggests early contact with hepatitis B virus, possibly due to vertical transmission and intrafamiliar dissemination of the disease; the frequency of anti-HBs increases with age; the lower prevalence of anti-HBs among those with low income suggests that this group may present higher prevalence of carriers of the hepatitis B virus surface antigen.

Relationship between the prevalence of antibodies to arbovirus and hepatitis B virus in the Vale do Ribeira region, Brazil

280 students, between 6 and 14 years old, residents in the Iguape county, southern coast of the State of São Paulo, were studied in order to identify the existence of a possible association between the prevalence of specific antibodies to the hepatitis B virus and the exposure to haematophagous mosquitoes, evaluated indirectly through the prevalence of antibodies to 17 arboviruses isolated in Brazil. The children were from 4 areas with different topographical characteristics: 89 of the children were from the urban zone of the town of Iguape, 89 were from the periurban zone, 30 were from the rural area with extensive banana plantations, and 72 were from the jungle zone. Previous studies had shown significantly higher prevalence of antibodies to different arboviruses in the cultivated zone and the jungle zone, when compared to the urban and periurban zones of Iguape. The detection of antibodies to the HBV surface antigen (HBs Ag) was done through the radioimmunoassay (Ausab, Abbott Laboratory). The cases considered positive were confirmed through the presence of anti-core HBV antibodies (anti-HBc-EIA Roche). A significantly higher prevalence of anti-HBV antibodies was observed in children from the jungle zone (26/72 = 36,1% ) when compared to those from the urban zone (5/89 = 5,6%), peri-urban (6/89 = 6,7%) or from the cultivated zone (0/30 = 0%). The result suggest the existence of a common factor in the dissemination of the arboviruses and the hepatitis B virus, supporting the hypothesis that mosquitoes may play an important role in the HBV transmission in tropical forested region.

Comparison of serum hepatitis B virus replication markers in patients with chronic hepatitis B: studies on HBeAg/Anti-HBe system, viral dna polymerase and HBV-DNA

The detection of HBV-DNA in serum by molecular hybridization is the most sensitive and specific marker of replication and infectivity of hepatitis B virus and currently is proposed as a routine diagnostic technique in the follow-up of HBV - related diseases. Comparing different techniques already described, we found that direct spotting of serum samples on nitrocellulose membranes under vacuum filtration, followed by denaturing and neutralizing washes is more practical, simple, sensible and reproducible. DNA polymerase assay using phosphonoformic acid as specific viral inhibitor has shown 86.8% of concordance with HBV-DNA detection, and so, it is an useful alternative in the follow-up of hepatitis B chronic patients. We found 19.2% HBeAg positive samples with no other markers of viral replication and no anti-HBe positive sample had detectable HBV-DNA. Discordance between the 2 systems have been extensively described, and we confirm this for the first time in our country. Molecular biological techniques are essential to determine the replication status of chronic hepatitis B patients.

Associantion between leprosy and hepatitis B infecion: a survey in Goiânia, Central Brazil

This investigation presents the results of Hepatitis B virus screening among leprosy patients conducted in Central Brazil as a preliminary information for a HBV vaccination programme. The main objectives were to assess the seroprevalence of HBV serum markers among lepromatous patients and to analyse institutionalization as risk factor for HBV infection in this population. Two groups of lepromatous patients were studied, 83 outpatients and 171 institutionalized ones. Screening for HBV serum markers included the detection of HBsAg, anti-HBc by radioimmune assay (RIA). The prevalence of carrier state (HBsAg) was 4.8% and 8.8% among outpatients and institutionalized, respectively, (p>0.05). Seroprevalence of exposure (all markers) was statistically significant different between outpatients (16.9%) and institutionalized ones (50.3%). Institutionalized patients had an almost four fold risk of HBV infection when compared to the outpatients, and the highest risks were among patients with more than 21 years of residence in the colony, after adjusting for age and sex.

Detection of hepatitis B virus DNA by the polymerase chain reaction in anti-HBE positive chronic hepatitis B patients

Detection of HBV-DNA by PCR was compared with other serological markers (HBsAg, HBeAg and anti-HBe) in a series of49 Chronic Hepatitis B patients, including 12 with a spontaneous clearance of HBsAg. None of these HBsAg negative cases were PCR positive, but 33/37 (89.2%) HBsAg positive cases were PCR positive (p < 0.0001). Among HBsAg positive samples, nine cases were HBeAg positive and anti-HBe negative, all of them PCR positive. Other 3 patients were HBeAg and anti-HBe positive and these cases were also found PCR positive. A third group included 21 patients anti-HBe positive and HBeAg negative: 19 of them were PCR positive and 2 were PCR negative. The last 4 cases were HBeAg and anti-HBe negative, two of them were PCR positive. The detection of anti-HBe viremic cases in the present series suggest that preC variants could occur in our country. In conclusion, the integrated phase o f chronic hepatitis B seems to be less frequent than it was assumed, when only HBeAg or dot blot hybridization techniques were used. The new term "low replication phase" might favorably replace the former "integrated phase".

Seasonal variation of hepatitis A virus infection in the city of Rio de Janeiro, Brazil

Hepatitis A virus (HAV) infection constitutes a major public health problem in Brazil. The transmission of HAV is primarily by fecal-oral route so the water is an important vehicle of HAV dissemination. There is a great incidence of acute cases of hepatitis A in some areas of Brazil however the seasonal variation of these cases was not documented. The aim of this study was to determine the seasonality of HAV infection in Rio de Janeiro. From January 1999 to December 2001, 1731 blood samples were collected at the National Reference Center for Hepatitis Viruses in Brazil (NRCHV). These samples were tested by a commercial enzyme-immunoassay to detect anti-HAV IgM antibodies. Yearly positive rates were 33.74% in 1999, 32.19% in 2000, and 30.63% in 2001. A seasonal variation was recognized with the highest incidence in spring and summer. Furthermore a seasonal increase in incidence of HAV infection was found during the rainy season (December to March) because the index of rains is very high. It is concluded that HAV infections occur all year round with a peak during hot seasons with great number of rains.

Immunogenicity of three recombinant hepatitis B vaccines administered to students in three doses containing half the antigen amount routinely used for adult vaccination

We evaluated the immunogenicity of three recombinant hepatitis B vaccines, one Brazilian (Butang, Instituto Butantan) and two Korean vaccines (Euvax-B, LG Chemical Ltd. and Hepavax-Gene, Greencross Vaccine Corp.), administered intramuscularly to students aged 17 to 19 years in three 10-µg doses (corresponding to half the amount of antigen routinely used for adult vaccination) at intervals of one month between the first and second dose, and of four months between the second and third dose. A total of 316 students non-reactive for any serological marker of hepatitis B virus infection were vaccinated: 77 (24.4%) with the Butang vaccine, 71 (22.5%) with Euvax-B, 85 (26.9%) with Hepavax-Gene and, for comparison, 83 (26.2%) with Engerix-B (GlaxoSmithKline), whose efficacy in young adults at the dose used here has been confirmed in previous studies. Similar seroconversion rates (anti-HBs > 10 mIU/mL about one month after application of the third dose) were obtained for the Butang, Euvax-B, Hepavax-Gene and Engerix-B vaccines (96.2%, 98.6%, 96.5% and 97.6%, respectively). The frequency of good responders (anti-HBs > 100 mIU/mL) was also similar among students receiving the four vaccines (85.8%, 91.6%, 89.4% and 89.2%, respectively). The geometric mean titers (GMT) of anti-HBs about one month after the third dose obtained with these vaccines were 727.78 ± 6.46 mIU/mL, 2009.09 ± 7.16 mIU/mL, 1729.82 ± 8.85 mIU/mL and 2070.14 ± 11.69 mIU/mL, respectively. The GMT of anti-HBs induced by the Euvax-B and Engerix-B vaccines were higher than those obtained with the Butang vaccine (p < 0.05); this difference was not significant when comparing the other vaccines two-by-two. No spontaneous adverse effects attributable to the application of any dose of the four vaccines were reported.

Serological, epidemiological and molecular aspects of hepatitis C virus infection in a population from Londrina, PR, Brazil, 2001-2002

Serological, epidemiological and molecular aspects of hepatitis C virus (HCV) infection were evaluated in 183 subjects from Londrina, Paraná, Brazil, and adjacent areas. Serum samples which tested anti-HCV positive by microparticle enzyme immunoassay (MEIA) obtained from eight patients with chronic hepatitis C, 48 blood donors, and 127 patients infected with the human immunodeficiency virus (HIV) were submitted to another enzyme immunoassay (ELISA) and to the polymerase chain reaction (PCR). About 78.7% of samples were also reactive by ELISA, with the greater proportion (70.8%) of discordant results verified among blood donors. A similar finding was observed for HCV-RNA detection by PCR, with 111/165 (67.3%) positive samples, with higher rates among HIV-positive subjects and patients with chronic hepatitis than among blood donors. Sixty-one PCR-positive samples were submitted to HCV genotyping, with 77.1, 21.3 and 1.6% of the samples identified as types 1, 3 and 2, respectively. Finally, analysis of some risk factors associated with HCV infection showed that intravenous drug use was the most common risk factor among HIV/HCV co-infected patients, while blood transfusion was the most important risk factor in the group without HIV infection. The present study contributed to the knowledge regarding risk factors associated with HCV infection and the distribution of HCV genotypes in the population evaluated.

Characterization of a Hepatitis B virus strain in southwestern Paraná, Brazil, presenting mutations previously associated with anti-HBs Resistance

The present study investigated if hepatitis B virus (HBV) mutants circulate in the southwestern region of the State of Paraná, Brazil, by analyzing samples from children who received immunoprophylaxis but were born to HBV carrier mothers. Samples from 25 children were screened for HBV serum markers and for HBV DNA by PCR. Only one sample was positive for HBsAg, anti-HBs and HBV DNA, although the child had been vaccinated. Analysis of the S gene sequence of this sample showed the presence of a proline at position 105, a serine at position 114, three threonines at positions 115, 116 and 140, and a glutamine at position 129. The presence of these amino acids, except for serine at position 114, has been related to monoclonal or polyclonal therapy with anti-HBs after liver transplantation, whereas the presence of threonine at position 116 has been described in immunized children from Singapore. This finding demonstrates the possible circulation of HBV strains resistant to hepatitis B immunoprophylaxis in southwestern Paraná, Brazil. The genotype of the sample was identified as genotype D, which is frequently found in the region studied. Since 36% of the children had received incomplete or no immunoprophylaxis, more extensive follow-up of children born to HBsAg-positive mothers is needed.

Hepatitis C virus infection in hemodialysis patients in Maracaibo, Venezuela

Over a two year period, the incidence of hepatitis C virus (HCV) infection was evaluated in 29 hemodialysis patients, aged between 15 and 75 years (mean ± SD: 45 ± 39.5 years), from the University Hospital Hemodyalisis Unit, Maracaibo, Zulia State, Venezuela. Anti-HCV antibodies were determined using a fourth generation ELISA (Innotest HCV Ab IV) kit and positive blood samples were tested using a recombinant assay kit (Inno-LIA HCV Ab III), both kits from Innogenetics N.V., Belgium. The findings indicate a lack of HCV seroconversion in the hemodialysis patients over the study period, confirmed by the recombinant assay. Risk factors for HCV infection were 0.3270 (95% confidence interval: 0.01323-8.080) in patients undergoing hemodialysis. The findings suggest a lack of significant sources for HCV infection due to the preventive measures to avoid its transmission in the hemodialysis unit.