1000 resultados para occult infection


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Hepatitis B virus (HBV) molecular profiles were determined for 44 patients who were infected with human immunodeficiency virus (HIV) type 1 and had antibodies to the hepatitis B core antigen (anti-HBc), with and without other HBV serological markers. In this population, 70% of the patients were under lamivudine treatment as a component of antiretroviral therapy. HBV DNA was detected in 14 (32%) patients. Eight out of 12 (67%) HBsAg positive samples, 3/10 (30%) anti-HBc only samples, and 3/22 (14%) anti-HBs positive samples were HBV DNA positive. HBV DNA loads, measured by real time polymerase chain reaction, were much higher in the HBsAg positive patients (mean, 2.5 × 10(9) copies/ml) than in the negative ones (HBV occult infection; mean, 2.7 × 10(5) copies/ml). Nine out of the 14 HBV DNA positive patients were under lamivudine treatment. Lamivudine resistant mutations in the polymerase gene were detected in only three patients, all of them belonging to the subgroup of five HBsAg positive, HBV DNA positive patients. A low mean HBV load (2.7 × 10(5) copies/ml) and an absence of lamivudine resistant mutations were observed among the cases of HBV occult infection.

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INTRODUCTION: Persistence of the hepatitis B virus (HBV) genome in individuals negative for the HBV surface antigen (HBsAg) reflects occult infection. The aim of this study was to identify occult HBV infection among hemodialysis patients at 5 clinics in Recife, State of Pernambuco, Brazil, between August 2006 and August 2007. METHODS: Serum samples underwent enzyme-linked immunosorbent assay to investigate total antibodies against HBcAg (anti-HBc), HBsAg, and antibodies against HBsAg (anti-HBs). Samples that were HBsAg-negative were tested for total anti-HBc, and those that were positive for total anti-HBc were tested for anti-HBs. HBV DNA was investigated with an in-house PCR technique to identify samples positive for total anti-HBc. Subsequently, the samples positive for HBV DNA were sequenced to identify the genotype and mutations. RESULTS: The study population (n = 752) had a mean age of 50 15.1 years and included both sexes. All samples analyzed were negative for HBsAg. The seroprevalence of total anti-HBc was 26.7% (201/752), while that of anti-HBs was 67.2% (135/201). Total anti-HBc alone was detected in 5.7% of the patients. Occult infection was found in 1.5%, comprising genotypes A (33.3%, 1/3) and D (66.7%, 2/3). No mutations were found. CONCLUSIONS: The study detected occult hepatitis B virus infection in hemodialysis patients. Molecular studies on HBV are of fundamental importance because they identify patients that had been considered virus-negative but who, in reality, host the virus and have the ability to transmit it to other patients and staff.

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The prevalence of occult hepatitis B virus (HBV) infection was investigated in 149 hepatitis B surface antigen (HBsAg) negative injecting drug users (IDUs) in the Central-West Region of Brazil. Of these individuals, 19 were positive for HBV DNA, resulting in an occult HBV infection prevalence of 12.7% (19/149); six of these 19 individuals had anti-HBV core and/or anti-HBV surface antibodies and 13 were negative for HBV markers. All IDUs with occult hepatitis B reported sexual and/or parenteral risk behaviours. All HBV DNA-positive samples were successfully genotyped. Genotype D was the most common (17/19), followed by genotype A (2/19). These findings reveal a high prevalence of occult HBV infection and the predominance of genotype D among IDUs in Brazil's Central-West Region.

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Anti-HBc positivity is a frequent cause of donation rejection at blood banks. Hepatitis B virus (HBV) infection may also occur in HBsAg-negative patients, a situation denoted occult infection. Similarly, very low levels of HBV-DNA have also been found in the sera of patients with chronic hepatitis C virus (HCV) infection, even in the absence of serum HBsAg. Initially we searched for HBV-DNA in serum of 100 blood donors and 50 HCV-infected patients who were HBsAg negative/anti-HBc positive by nested-PCR and by an HBV monitor commercial test for HBV-DNA. Anti-HBs seroconversion rates were measured in 100 blood donors and in 22 patients with chronic HCV infection after HBV vaccination to determine if the HBV vaccination could eliminate an occult HBV infection in these individuals. Occult HBV infection was detected in proportionally fewer blood donors (6/100 = 6%) than chronic hepatitis C patients (12/50 = 24%) (P < 0.05). We noted seroconversion in 6/6 (100%) HBV-DNA(+) and in 84/94 (89.4%) HBV-DNA(-) blood donors (P > 0.05). All subjects who were HBV-DNA(+) before the first dose of HBV vaccine (D1), became HBV-DNA(-) after D1, D2, and D3. Among 22 HCV-positive patients, 10 HBV-DNA(+) and 12 HBV-DNA(-), seroconversion was observed in 9/10 (90%) HBV-DNA(+) and in 9/12 (75%) HBV-DNA(-) subjects (P > 0.05). The disappearance of HBV-DNA in the majority of vaccinated patients suggests that residual HBV can be eliminated in patients with occult infection.

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INTRODUCTION: Occult hepatitis B infection (OBI) is considered to be one of the major risks for patients suffering from end-stage renal disease (ESRD) on regular hemodialysis (HD) and patients with chronic hepatitis C virus (HCV) infection. This study compared the prevalence of OBI among these two high-risk groups in the Suez Canal region, Northeastern Egypt, to obtain a better national overview of the magnitude of OBI in this region. METHODS: Serum samples were collected from 165 HD patients and 210 chronic HCV-infected patients. Anti-HCV antibody, hepatitis B surface antigen (HBsAg), total hepatitis B core (anti-HBc) antibody, and hepatitis B surface antibody (anti-HBs) were detected by enzyme-linked immunosorbent assay (ELISA). HCV RNA was detected using a quantitative real-time RT-PCR assay, and HBV was detected using a nested PCR. RESULTS: All patients were negative for HBsAg. A total of 49.1% and 25.2% of the patients in the HD and HCV groups, respectively, were anti-HBc-positive. In addition, more anti-HBs-positive patients were detected in the HD group compared to the HCV group (52.1% and 11.4%, respectively). Three cases were positive for HBV DNA in the HD group, while eighteen positive cases were detected in the HCV group. Both study groups showed significant differences in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level as well as anti-HBc, anti-HBs and HBV-DNA positivity. CONCLUSIONS: OBI was more prevalent among chronic HCV patients than HD patients in the Suez Canal region, Egypt, with rates of 8.5% and 1.8%, respectively. However, more precise assessment of this infection requires regular patient follow-up using HBV DNA detection methods.

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In this cross-sectional study, 207 hepatitis B surface antigen (HBsAg)-negative kidney transplant recipients were evaluated based on demographic and epidemiological data and on the levels of serological markers of hepatitis B virus (HBV) and hepatitis C virus infection and liver enzymes. Patients with HBV or human immunodeficiency virus infection were excluded. Sera were analysed for the presence of HBV-DNA. HBV-DNA was detected in two patients (1%), indicating occult hepatitis B (OHB) infection (the HBV-DNA loads were 3.1 and 3.5 IU/mL in these patients). The results of the liver function tests were normal and no serological markers indicative of HBV infection were detected. The prevalence of OHB infection was low among kidney transplant recipients, most likely due to the low HBsAg endemicity in the general population of the study area.

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Studies on the prevalence of infection with hepatitis B virus (HBV) among children are scarce in Latin American countries, especially in Mexico. This study was aimed to investigate the prevalence of HBV infection, occult hepatitis B infection (OBI) and HBV genotypes among children with clinical hepatitis. In total, 215 children with clinical hepatitis were evaluated for HBV infection. HBV serological markers and HBV DNA were analysed. OBI diagnosis and HBV genotyping was performed. HBV infection was found in 11.2% of children with clinical hepatitis. Among these HBV DNA positive-infected children, OBI was identified in 87.5% (n = 21/24) of the cases and 12.5% (n = 3/24) were positive for both HBV DNA and hepatitis B surface antigen. OBI was more frequent among children who had not been vaccinated against hepatitis B (p < 0.05) than in those who had been vaccinated. HBV genotype H was prevalent in 71% of the children followed by genotype G (8%) and genotype A (4%). In conclusion, OBI is common among Mexican children with clinical hepatitis and is associated with HBV genotype H. The results show the importance of the molecular diagnosis of HBV infection in Mexican paediatric patients with clinical hepatitis and emphasise the necessity of reinforcing hepatitis B vaccination in children.

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Occult hepatitis B virus (HBV) infection has been reported among patients with hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC). Our aim was to evaluate the presence of occult HBV infection in patients with HCV-related liver cirrhosis (LC) with or without HCC in São Paulo, Brazil. Serum and liver tissue samples from 50 hepatitis B surface antigen-negative patients with HCV-related LC who underwent liver transplantation at the University of São Paulo School of Medicine Hospital from 1993 to 2004 were divided into groups with LC only (N = 33) and with LC plus HCC (N = 17). HBV DNA was assayed for serum and paraffin-embedded liver tissue (tumoral and non-tumoral) using real time PCR and only 1 case with HCC had HBV DNA-positive serum. All liver samples were negative. HCV genotype 3 was detected in 17/39 (43.7%) cases. In conclusion, using a sensitive real time PCR directed to detect HBV variants circulating in Brazil, occult hepatitis B infection was not found among HCV-positive cirrhotic patients and was rarely found among HCV-positive HCC patients. These results are probably related to the low prevalence of HBV infection in our population. Furthermore, we have also shown that HCV genotype 3 is frequently found in Brazilian cirrhotic patients, particularly when they also have HCC. More studies involving a large number of cases should be carried out to confirm these data and to further characterize Brazilian HCV genotype isolates to elucidate genetic features that might be related to its carcinogenic potential.

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Estimates of occult hepatitis B virus (HBV) infection prevalence varies among different studies depending on the prevalence of HBV infection in the study population and on the sensitivity of the assay used to detect HBV DNA. We investigated the prevalence of occult HBV infection in cirrhotic patients undergoing liver transplantation in a Brazilian referral center. Frozen liver samples from 68 adults were analyzed using a nested polymerase chain reaction assay for HBV DNA. The specificity of the amplified HBV sequences was confirmed by direct sequencing of the amplicons. The patient population comprised 49 (72.1%) males and 19 (27.9%) females with a median age of 53 years (range=18-67 years). Occult HBV infection was diagnosed in three (4.4%) patients. The etiologies of the underlying chronic liver disease in these cases were alcohol abuse, HBV infection, and cryptogenic cirrhosis. Two of the patients with cryptic HBV infection also presented hepatocellular carcinoma. Markers of previous HBV infection were available in two patients with occult HBV infection and were negative in both. In conclusion, using a sensitive nested polymerase chain reaction assay to detect HBV DNA in frozen liver tissue, we found a low prevalence of occult HBV infection in cirrhotic patients undergoing liver transplant, probably due to the low prevalence of HBV infection in our population.

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INTRODUCTION: This study aimed to estimate the prevalence of HBV infection and associated factors among prison inmates in Campo Grande, MS. METHODS: A total of 408 individuals were interviewed regarding sociodemographic characteristics, associated factors and HBV vaccination using a standardized questionnaire. Blood samples were collected from all participants and serological markers for HBV were detected by enzyme-linked immunosorbent assay. Hepatitis B surface antigen (HBsAg) and/or antibodies against hepatitis B core antigen (anti-HBc) positive samples were tested for HBV-DNA by polymerase chain reaction. RESULTS: The overall prevalence of HBV infection was 17.9% (95%CI: 14.4-22.0). The HBsAg carrier rate was 0.5%; 56 (13.7%) individuals had been infected and developed natural immunity and 15 (3.7%) were positive for anti-HBc only. Ninety eight (24%) prisoners had only anti-HBs, suggesting that they had low vaccine coverage. An occult HBV infection rate of 0% was verified among anti-HBc-positive individuals. Multivariate analysis of associated factors showed that age > 35 years-old, low schooling level and illicit drug use are significantly associated with HBV infection. CONCLUSIONS: Analysis of the data showed HBV infection prevalence similar or slightly lower than that reported in other of Brazilian prisons. Independent predictors of HBV infection in this population include older age, low schooling level and illicit drug use.

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Introduction: The collection of recyclable waste materials is a widespread activity among the urban poor. Today, this occupation attracts an increasingly large number of individuals. Despite its economic and environmental importance, this activity is associated with unsafe and unhealthy working conditions. The aim of this study was to investigate the seroepidemiological profile of hepatitis B virus (HBV) infection in a population of recyclable waste collectors in central Brazil. Methods: Recyclable waste collectors from all 15 recycling cooperatives in Goiânia City were invited to participate in the study. The participants (n = 431) were interviewed and screened for hepatitis B surface antigen (HBsAg) and antibodies against HBsAg (anti-HBs) and hepatitis B core antigen (anti-HBc) by enzyme-linked immunosorbent assay (ELISA). HBsAg- and anti-HBc-positive samples were tested for HBV DNA and genotyped. Results: The overall prevalence of HBV infection (HBsAg- and/or anti-HBc-positive) was 12.8%. An age over 40 years and illicit drug use were associated with HBV infection. HBV DNA was detected in 2/3 HBsAg-positive samples and in 1/52 anti-HBc-positive/HBsAg-negative samples (an occult HBV infection rate of 1.9%), in which the genotypes/subgenotypes A/A1, D/D3 and F/F2 were identified. Only 12.3% of the recyclable waste collectors had serological evidence of previous HBV vaccination. Conclusions: These findings highlight the vulnerability of recyclable waste collectors to HBV infection and reinforce the importance of public health policies that address the health and safety of this socially vulnerable population.

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A high prevalence of occult hepatitis B (OHB) genotype H infections has been observed in the native Mexican Nahua population. In addition, a low incidence of hepatitis B virus (HBV)-associated hepatocellular carcinoma has been described in Mexico. The immune response to infection among OHB-infected patients has been poorly evaluated in vivo. Therefore, we assessed the expression profiles of 23 cytokines in OHB genotype H-infected Nahua patients. A total of 41 sera samples from natives of the Nahua community were retrospectively analysed. Based on their HBV antibody profiles, patients were stratified into two groups: OHB patients (n = 21) and patients that had recovered from HBV infection (n = 20). Herein, we report distinctive cytokines profiles in OHB-infected individuals. Compared to healthy controls (n = 20) and patients who resolved HBV infection, OHB-infected patients displayed an increase in interleukin (IL)-2 secretion in addition to a characteristic inflammation profile (decrease in IL-8 and tumour necrosis factor-alpha levels and increased levels of tumour growth factor-beta). IL-15 and interferon-gamma levels were reduced in OHB-infected individuals when compared to those patients who resolved HBV infection. In contrast, OHB patients showed an increase in monocyte chemoattractant protein (MCP)-1 and MCP-2 compared to healthy controls and patients who resolved HBV infection. These findings suggest that cytokine expression can influence the severity of OHB disease and could lead to new investigation into the treatment of liver and other infectious diseases.

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Little is known about the long-term survivors of acute arsenic intoxication. We present here a clinical case report of a man with chronic hepatitis B virus (HBV) infection who developed hepatocellular carcinoma four years after acute arsenic poisoning. HBsAg was detected in serum in 1990 when he voluntarily donated blood. In 1991, the patient suffered from severe psychological depression that led him to attempt suicide by massive ingestion of an arsenic-containing rodenticide. He survived with polyneuropathy and paralysis of the lower limbs, and has been wheelchair-bound since then. During participation in a follow-up study conducted among HBV carriers, abdominal ultrasound detected a two-centimeter liver mass consistent with hepatocellular carcinoma. The tumor was confirmed by computed tomography (CT) and magnetic resonance image (MRI). Because of his significant comorbidity, the patient received palliative treatment with transarterial lipiodol chemoembolization (TACE) on three occasions (1996, 1997 and 1999). At his most recent visit in May 2005, the patient was asymptomatic, liver enzymes were normal and the tumor was in remission on ultrasound.

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The increase in solid organ transplantations may soon create a rise in the occurrence of endemic fungal diseases, such as paracoccidioidomycosis, due to the lack of rigorous screening of donors from endemic areas. Here we present the first case of an immunocompetent and asymptomatic kidney donor who had Paracoccidioides brasiliensis infected-adrenal tissue but no glandular dysfunction.