Hepatitis C prevalence and risk factors in hemodialysis patients in Central Brazil: a survey by polymerase chain reaction and serological methods

An hemodialysis population in Central Brazil was screened by polymerase chain reaction (PCR) and serological methods to assess the prevalence of hepatitis C virus (HCV) infection and to investigate associated risk factors. All hemodialysis patients (n=428) were interviewed in eight dialysis units in Goiânia city. Blood samples were collected and serum samples screened for anti-HCV antibodies by an enzyme-linked immunosorbent assay (ELISA). Positive samples were retested for confirmation with a line immunoassay (LIA). All samples were also tested for HCV RNA by the PCR. An overall prevalence of 46.7% (CI 95%: 42-51.5) was found, ranging from 20.7% (CI 95%: 8.8-38.1) to 90.4% (CI 95%: 79.9-96.4) depending on the dialysis unit. Of the 428 patients, 185 were found to be seropositive by ELISA, and 167 were confirmed positive by LIA, resulting in an anti-HCV prevalence of 39%. A total of 131 patients were HCV RNA-positive. HCV viremia was present in 63.5% of the anti-HCV-positive patients and in 10.3% of the anti-HCV-negative patients. Univariate analysis of risk factors showed that the number of previous blood transfusions, transfusion of blood before mandatory screening for anti-HCV, length of time on hemodialysis, and treatment in multiple units were associated with HCV positivity. However, multivariate analysis revealed that blood transfusion before screening for anti-HCV and length of time on hemodialysis were significantly associated with HCV infection in this population. These data suggest that nosocomial transmission may play a role in the spread of HCV in the dialysis units studied. In addition to anti-HCV screening, HCV RNA detection is necessary for the diagnosis of HCV infection in hemodialysis patients.

Additives and Protein-DNA Combinations Modulate the Humoral Immune Response Elicited by a Hepatitis C Virus Core-encoding Plasmid in Mice

Humoral and cellular immune responses are currently induced against hepatitis C virus (HCV) core following vaccination with core-encoding plasmids. However, the anti-core antibody response is frequently weak or transient. In this paper, we evaluated the effect of different additives and DNA-protein combinations on the anti-core antibody response. BALB/c mice were intramuscularly injected with an expression plasmid (pIDKCo), encoding a C-terminal truncated variant of the HCV core protein, alone or combined with CaCl2, PEG 6000, Freund's adjuvant, sonicated calf thymus DNA and a recombinant core protein (Co.120). Mixture of pIDKCo with PEG 6000 and Freund's adjuvant accelerated the development of the anti-core Ab response. Combination with PEG 6000 also induced a bias to IgG2a subclass predominance among anti-core antibodies. The kinetics, IgG2a/IgG1 ratio and epitope specificity of the anti-core antibody response elicited by Co.120 alone or combined with pIDKCo was different regarding that induced by the pIDKCo alone. Our data indicate that the antibody response induced following DNA immunization can be modified by formulation strategies.

Relation between Hepatitis B Carrier Status and Antibody against Synthetic Plasmodium falciparum Erythrocyte Surface (pf155 - RESA) Antigen

A survey on Plasmodium infection was carried out in gold mine camps located in the Brazilian Amazon. Antibody against P. falciparum ring-infected erythrocyte surface antigen (RESA) was quantified by an enzyme-immunoassay in order to assess P. falciparum exposure. Hepatitis B, a common infection in this area, was also investigated by serologic markers. Among 520 sampled subjects, 517 (99.4%) admitted previous symptomatic malaria, 106 (20.4%) had positive thick smears for malaria, 82.9% had HBV markers, and 7.1% were HBsAg positive. Anti-RESA titers was significantly lower in HBV carriers than in people with resolved HBV infection suggesting that the anti-RESA immune response could be supressed by HBV carrier status. Moreover, immunedeficient responses to both infections may take place in some subjects causing concomitant lower anti-RESA response and incapacity to clear HBV.

Hepatitis A Outbreak in a Public School in Rio de Janeiro, Brazil

From June 1 to July 1 1999, an outbreak involving 25 cases of hepatitis A occurred in a public school in Rio de Janeiro, Brazil. Since these cases were notified to the State Health Department, the National Reference Center for Hepatitis Viruses (CNRHV) was required to investigate the extent of hepatitis A virus (HAV) dissemination. Blood samples from all students were tested for IgM and total anti-HAV antibodies using a commercial enzyme-linked immunoassay (ELISA). At the same time, a questionnaire was completed in order to identify possible risk factors for HAV infection. The environmental investigation showed that there was no fecal contamination of the water supply. The epidemiological investigation demonstrated that almost 50% of this population was susceptible to HAV infection and probably person-to-person transmission was the principal mode of virus dissemination. In this situation, a massive vaccination campaign could control the HAV infection.

Lack of Correlation between Seminal and Plasma HIV-1 Viral Loads is Associated with CD4T Cell Depletion in Therapy-naïve HIV-1+ Patients

The present study was conducted to investigate a possible correlation between plasma (PVL) and seminal viral load (SVL) on treatment-naïve HIV-1-infected patients in Vitória, ES, Brazil. We also evaluated whether the progressive immunosuppression associated with HIV disease (as evidenced by declining CD4 T cell counts) has any impact on the correlation between PVL and SVL HIV-1. Viral load on paired blood and semen samples from 56 consecutive treatment-naïve patients were evaluated and compared to CD4 cell counts. Viral load and T cell counts (cells/µl) were determined by NASBA and by flow cytometry, respectively. Overall, a strong positive correlation between PVL and SVL (rho = 0.438, p = 0.001) was observed. However, when patients were grouped according to their CD4 counts, this correlation was only significant among patients with CD4 counts > 200 cells/µl. Results presented here demonstrate the existence of a strong correlation between PVL and SVL on patients with CD4 cell counts > 200 cells/µl, suggesting that this association may correlate with disease progression.

Prevalence of hepatitis C Virus infection among hemophiliacs in Central Brazil

In order to investigate the hepatitis C virus (HCV) infection prevalence and risk factors in hemophiliacs in Central Brazil, 90 patients were interviewed and serum samples tested for HCV RNA and anti-HCV antibodies. An overall prevalence of 63.3% (CI 95%: 53.0-72.7) was found. Multivariate analysis of risk factors showed that number of blood transfusions was significantly associated with this infection. Most hemophiliacs received locally produced cryoprecipitate. All infected patients were transfused before the screening of blood units for anti-HCV. However, hemophiliacs who received exclusively screened cryoprecipitate were HCV negative. It confirms the expected decline in transfusion-acquired hepatitis C.

Hepatitis C and hepatitis B virus infection in different hemodialysis units in Belo Horizonte, Minas Gerais, Brazil

The prevalence, virological and epidemilogical aspects of the hepatitis C virus (HCV) and the hepatitis B virus (HBV) infections vary among hemodialysis patients in different countries. Aiming at analyzing these aspects of HCV and HBV infections in hemodialysis patients in Belo Horizonte, MG, Brazil, we studied three hemodialysis units including 434 patients. Serology was used to detect anti-HCV and HBsAg. Reverse trancriptase nested polymerase chain reaction (RT-nested-PCR) of the 5'-noncoding region was used to detect circulating HCV RNA and restriction fragment length polymorphism analysis for genotyping. Seroprevalence varied from 26.5% to 11.1% for hepatitis C and from 5.9% to 0% for hepatitis B. Risk factors observed for HBV and/or HCV infections were the number of patients per dialysis unit, duration of treatment, number of clinics attended, number of blood units transfused, and lower level scholarity. Alanine aminotransferase levels were altered with a higher frequency in HBV or HCV seropositive patients. Half of ten patients, negative for anti-HCV, had detectable viremia by RT-nested-PCR, indicating that this technique should be used to confirm infections in this group of patients. The HCV genotype 1 was the most frequently observed, followed by the genotype 2, but no correlation was detected between genotype and clinical or epidemiological data.

Prevalence and genotypes of GB Virus C/Hepatitis G virus among blood donors in Central Brazil

A survey was conducted in a blood donor population of Central Brazil aiming to investigate the prevalence of GB virus C (GBV-C)/hepatitis G virus (HGV) infection and also to analyze the virus genotypes distribution. A total of 241 voluntary blood donors were interviewed at the State Blood Bank in Goiânia, State of Goiás, Brazil. Blood samples were collected and serum samples tested for GBV-C/HGV RNA by polymerase chain reaction. Genotypes were determined by restriction fragment length polymorphism (RFLP) analysis. Seventeen samples were GBV-C/HGV RNA-positive, resulting in a prevalence of 7.1% (95% CI: 4.2-11.1). A significant trend of GBV-C/HGV RNA positivity in relation to age was observed, with the highest prevalence in donors between 29-39 years old. Ten infected individuals were characterized by reporting parenteral (30%), sexual (18%), both (6%) and intrafamiliar (6%) transmission. However, 7 (40%) GBV-C/HGV RNA-positive donors did not mention any potential transmission route. RFLP analysis revealed the presence of genotypes 1 and 2 of GBV-C/HGV; more precisely, 10 (58.9%) samples were found belonging to the 2b subtype, 4 (23.5%) to the 2a subtype, and 3 (17.6%) to genotype 1. The present data indicate an intermediate endemicity of GBV-C/HGV infection among this blood donor population, and a predominant circulation of genotype 2 (subtype 2b) in Central Brazil.

Seroprevalence of Hepatitis B virus infection among an afro-descendant community in Brazil

Furnas dos Dionísios is an Afro-Brazilian black community whose descendants were mainly fugitive slaves that established themselves in the State of Mato Grosso do Sul (MS), Brazil. The population is comprised mainly of low socioeconomic individuals who are engaged in agricultural activities. The objective of this study was to investigate the prevalence of hepatitis B (HB) and its correlation with epidemiological data obtained from the community. The studied population totaled 260 individuals with ages varying from 1 to 79 years (median 20). One hundred thirty-three (51.2%) were females and 127 (48.8%) were males. A high prevalence for anti-HBc was observed (42.7%), with present infection detected in 9.2% of the subjects who were also HB surface antigens (HBs Ag) positive; 27.3% were anti-HBc and anti-HBs reactive, and 6.2% had anti-HBc as only marker. The prevalence for anti-HBc was proportional to age, reaching its highest peak in age categories greater than 50. No serological marker was detected in children under the age of 2 years, however anti-HBc was present in 12 subjects with ages between 2 and 14 years, of these 8 (7.4%) were HBsAg positive. Among individuals over the age of 15 years, 99 were anti-HBc reactive, of these 16 (10.5%) were also HBsAg positive, thus suggesting an increased prevalence of HBV carriers among children and adolescents. The risk factors observed in this community that were significantly associated with anti-HBc positivity were age (over 20 years) and having an anti-HBc positive mother. Both HBeAg and anti-HBe were detected in 44.4% of the samples tested. HBsAg subtypes found in the studied population were adw2 (77.7%) and ayw2 (23.3%). While intrafamilial transmission was most likely responsible for HBV infection among children, other routes such as sexual contact might be considered for individuals with ages over 15 years.

Hepatitis B and C in the hemodialysis unit of Tocantins, Brazil: serological and molecular profiles

A survey was conducted in the hemodialysis population of the state of Tocantins, Brazil, aiming to assess the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, to analyze associated risk factors, and also to investigate these viruses genotypes distribution. During January and March 2001, all patients (n = 100) were interviewed at the unique dialysis unit in Tocantins. Blood samples were collected and serum samples were screened for HBV serological markers. Hepatitis B surface antigen positive samples were tested for HBV DNA. All samples were also tested for anti-HCV antibodies and HCV RNA. An overall prevalence of 45% was found for HBV infection (4% were HBsAg/anti-HBc positive, 2% were anti-HBc only and 39% had anti-HBc/anti-HBs markers). Concerning HCV infection, anti-HCV and HCV RNA were detected in 13% and 14% of the subjects, respectively. Three patients were HCV RNA positive and anti-HCV negative, resulting in an overall HCV prevalence of 16%. Univariate analysis of risk factors showed that only shift and length of time on hemodialysis were associated with HBV and HCV positivity, respectively. Among the four HBsAg-positive samples, HBV DNA was detected in three of them, which were identified as genotype A by restriction fragment length polymorphism (RFLP) analysis. All 14 HCV RNA-positive samples were genotyped by INNO-LiPA. Genotypes 1a and 3a were found in 85% and 15%, respectively. The present data show low HBsAg and HCV prevalence rates. The risk factors associated with HBV and HCV positivity suggest that nosocomial transmission may influence in spreading these viruses in the dialysis unit studied.

Respiratory syncytial virus infections during an epidemic period in Salvador, Brazil: viral antigenic group analysis and description of clinical and epidemiological aspects

Acute respiratory infections (ARI) caused by respiratory syncytial virus (RSV) were studied in 482 children from Salvador, BA, Brazil, over a period of 12 months. The epidemic period of RSV infections in Salvador occurred from February (summer) to August (winter), with peaks in May, June, and July. The grouping characteristics of 84 RSV present in nasopharyngeal secretions of children seen at a reference university hospital were analyzed. RSV represented 17.4% of all cases and 54.5% of the positive samples. Sixty-four RSV strains were assigned to group A and 14 to group B. Both groups circulated in the five months of the epidemic period studied. Infections by both groups of RSV were more frequent in children up to one year of age. The incidence of RSV ARI was slightly more frequent in males, although group B had more infected females.

Cytotoxicity and potential antiviral evaluation of violacein produced by Chromobacterium violaceum

Natural products are an inexhaustible source of compounds with promising pharmacological activities including antiviral action. Violacein, the major pigment produced by Chromobacterium violaceum, has been shown to have antibiotic, antitumoral and anti-Trypanosoma cruzi activities. The goal of the present work was to evaluate the cytotoxicity of violacein and also its potential antiviral properties.The cytotoxicity of violacein was investigated by three methods: cell morphology evaluation by inverted light microscopy and cell viability tests using the Trypan blue dye exclusion method and the MTT assay. The cytotoxic concentration values which cause destruction in 50% of the monolayer cells (CC50) were different depending on the sensitivity of the method. CC50 values were > 2.07 ± 0.08 µM for FRhK-4 cells: > 2.23 ± 0.11 µM for Vero cells; > 2.54 ± 0.18 µM for MA104 cells; and > 2.70 ± 0.20 µM for HEp-2 cells. Violacein showed no cytopathic inhibition of the following viruses: herpes simplex virus type 1 (HSV-1) strain 29-R/acyclovir resistant, hepatitis A virus (strains HM175 and HAF-203) and adenovirus type 5 nor did it show any antiviral activity in the MTT assay. However violacein did show a weak inhibition of viral replication: 1.42 ± 0.68%, 14.48 ± 5.06% and 21.47 ± 3.74% for HSV-1 (strain KOS); 5.96 ± 2.51%, 8.75 ± 3.08% and 17.75 ± 5.19% for HSV-1 (strain ATCC/VR-733); 5.13 ± 2.38 %, 8.18 ± 1.11% and 8.51 ± 1.94% for poliovirus type 2; 8.30 ± 4.24%; 13.33 ± 4.66% and 24.27 ± 2.18% for simian rotavirus SA11, at 0.312, 0.625 and 1.250 mM, respectively, when measured by the MTT assay.

Risk of hepatitis C among brazilian ex-soccer players

In order to evaluate the significance of injecting vitamins complexes and stimulants minutes before soccer games and its role in spread of hepatitis C virus (HCV) we interviewed and tested 40 ex-soccer players, who played professionally in Mato Grosso, Brazil, between 1970 and 1989. Five players were found anti-HCV positive with enzyme-immunoassay. When re-tested by imunoblot (RIBA), three of these five were confirmed to be positive reacting. The anti-HCV positivity (7.5%) was higher than usually found among blood donors (0.9%) in this region (p < 0.01). None of the players had had prior history of any risk factor that might indicate HCV exposure. We suggest that the common practice of soccer players in the inner part of Brazil in the 70's and 80's, to receive fortifying injections, often with shared syringes, may place ex-soccer players in a potencial risk group for HCV infection and warrants further investigation and attention by public health workers.

Intradermal vaccination of adults with three low doses (2 µg) of recombinant hepatitis B vaccine. I. Seroconversion rate and adverse effects

A total of 250 dentists (53.6% men and 46.4% women), with a mean age of 35.1 ± 9.8 years, were submitted to serological tests for the diagnosis of hepatitis B (HB) - HBsAg, anti-HBs, anti-HBc, HBeAg, and anti-HBe - using a radioimmunoassay. One or more of these markers were detected in 78 individuals (31.2%) who were excluded from the group to be vaccinated. Of the 172 HB-susceptible individuals, 135 (78.5%) responded to the call and were intradermally injected with three 2 µg doses of the Belgian HB recombinant vaccine, applied at an interval of one month between the 1st and 2nd dose and of five months between the 2nd and 3rd dose. A new determination of HB markers carried out 50 days after the 3rd dose showed that 110 (81.5%) individuals had become anti-HBs positive (65.5% good responders and 34.5% poor responders). Mean serum anti-HBs titer of these 110 dentists was 42.4 U S/N, similar in both sexes. The adverse effects analyzed in 106 dentists were: (a) local: pain (12.3%), burning sensation (14.1%), pruritus (25.5%), erythema (28.3%), local heat (18.9%), and a hypochromic spot (32.1%); (b) systemic (4.7%): discomfort in two patients, and fever, anorexia, and asthenia in one patient each. Intradermal administration of a fourth 2 µg vaccine dose to 39 dentists (poor or non-responders) increased the total number of anti-HBs-positive individuals from 110 (81.5%) to 114 (84.4%), with the number of good responders increasing from 72 (65.5%) to 85 (74.6%). We conclude that the Belgian recombinant vaccine applied in the scheme used here induces a high rate of seroconversion and causes only mild and transitory adverse effects.

Intradermal vaccination of adults with three low doses (2 µg) of recombinant hepatitis B vaccine. II. Persistence of immunity and induction of immunologic memory

Of the 110 dentists who had presented seroconversion 50 days after the intradermal application of three 2 µg doses of the Belgian recombinant vaccine against hepatitis B (HB), administered eight years before at an interval of one month between the 1st and 2nd doses and of five months between the 2nd and 3rd doses, 51 were included for the assessment of the persistence of immunity. None of the dentists had hepatitis or had received HB vaccine during this period. All subjects were submitted to serological tests for the detection of the following markers of hepatitis B virus (HBV) infection: HBsAg, anti-HBc, HBeAg, anti-HBe, and anti-HBs, with no HBsAg, anti-HBc, HBeAg or anti-HBe being detected. A microparticle enzyme immunoassay (MEIA) revealed the presence of anti-HBs at protective titers (> 10 mIU/ml) in 42 dentists (82.4%), with the anti-HBs titer being higher than 100 mIU/ml in 36 of them (70.6%) (good responders), between 10 and 100 mIU/ml in 6 (11.8%) (poor responders), and lower than 10 mIU/ml in 9 (17.6%) (non-responders). According to clinical data and serological tests, none of the dentists had presented disease or latent HBV infection during the eight years following the first vaccination. A 2 µg booster dose was administered intradermally to eight dentists with anti-HBs titers lower than 10 mIU/ml (non-responders) and to six dentists with titers ranging from 10 to 100 mIU/ml (poor responders); the determination of anti-HBs one month later demonstrated the occurrence of seroconversion in the eight non-responders and an increase in anti-HBs titer in the six poor responders. In summary, the present results demonstrated the prolonged persistence of protection against HBV infection and the development of immunologic memory provided by vaccination against HB - with intra-dermal application of three 2 µg doses of the Belgian recombinant vaccine at 0, 1, and 6 months - carried out eight years before in 51 dentists.