Hepatitis B virus infection in Haemodialysis Centres from Santa Catarina State, Southern Brazil. Predictive risk factors for infection and molecular epidemiology

Persistently high hepatitis C rates in haemodialysis patients in Brazil [a systematic review and meta-analysis]

We conducted a systematic review and meta-analysis of studies assessing HCV infection rates in haemodialysis patients in Brazil (Prospero CRD #42021275068). We included studies on patients under haemodialysis, comprising both convenience samples and exhaustive information from selected services. Patients underwent HCV serological testing with or without confirmation by HCV RNA PCR. Exclusion criteria were the following: absence of primary empirical information and studies without information on their respective settings, study year, accurate infection rates, or full specification of diagnostic tests. Studies with samples ≤ 30 and serial assessments with repeated information were also excluded. Reference databases included PubMed, LILACS, Scopus, and Web of Science for the period 1989–2019. A systematic review was carried out, followed by two independent meta-analyses: (i) studies with data on HCV prevalence and (ii) studies with a confirmatory PCR (i.e., active infection), respectively. A comprehensive set of different methods and procedures were used: forest plots and respective statistics, polynomial regression, meta-regression, subgroup influence, quality assessment, and trim-and-fill analysis. 29 studies and 11,290 individuals were assessed. The average time patients were in haemodialysis varied from 23.5 to 56.3 months. Prevalence of HCV infection was highly heterogeneous, with a pronounced decrease from 1992 to 2001, followed by a plateau and a slight decrease in recent years. The summary measure for HCV prevalence was 34% (95% CI 26–43%) for studies implemented before 2001. For studies implemented after 2001, the corresponding summary measure was 11% (95% CI 8–15%). Estimates for prevalence of active HCV infection were also highly heterogeneous. There was a marked decline from 1996 to 2001, followed by a plateau and a slight increase after 2010. The summary measure for active HCV infection was 19% (95% CI 15–25%) in studies carried out before 2001. For studies implemented after 2001, the corresponding summary measure was 9% (95% CI 6–13%). Heterogeneity was pervasive, but different analyses helped to identify its underlying sources. Besides the year each study was conducted, the findings differed markedly between geographic regions and were heavily influenced by the size of the studies and publication biases. Our systematic review and meta-analysis documented a substantial decline in HCV prevalence among Brazilian haemodialysis patients from 1992 to 2015. CKD should be targeted with specific interventions to prevent HCV infection, and if prevention fails, prompt diagnosis and treatment. Although the goal of HCV elimination by 2030 in Brazil remains elusive, it is necessary to adopt measures to achieve micro-elimination and to launch initiatives towards targeted interventions to curb the spread of HCV in people with CKD, among other high-risk groups. This is of particular concern in the context of a protracted COVID-19 pandemic and a major economic and political crisis.

Risk factors associated with nosocomial infections among end stage renal disease patients undergoing hemodialysis: A systematic review

Background

Profound healthcare challenges confront societies with an increase in prevalence of end-stage renal disease (ESRD), which is one of the leading causes of morbidity and mortality worldwide. Due to several facility and patient related factors, ESRD is significantly associated with increased morbidity and mortality attributed to infections.

Aims and objective

The aim of this study was to assess systematically the characteristics of patients and risk factors associated with nosocomial infections among ESRD patients undergoing hemodialysis.

Methods

A systematic literature search was performed to identify eligible studies published during the period from inception to December 2018 pertaining to risk factors associated with nosocomial infections among hemodialysis patients. The relevant studies were generated through a computerized search on five databases (PubMed, EBSCOhost, Google Scholar, ScienceDirect and Scopus) using the Mesh Words: nosocomial infections, hospital acquired infections, healthcare associated infections, end stage renal disease, end stage renal failure, hemodialysis, and risk factors. The complete protocol has been registered under PROSPERO (CRD42019124099).

Results

Initially, 1411 articles were retrieved. Out of these, 24 were duplicates and hence were removed. Out of 1387 remaining articles, 1337 were removed based on irrelevant titles and/or abstracts. Subsequently, the full texts of 50 articles were reviewed and 41 studies were excluded at this stage due to lack of relevant information. Finally, nine articles were selected for this review. Longer hospital stay, longer duration on hemodialysis, multiple catheter sites, longer catheterization, age group, lower white blood cell count, history of blood transfusion, and diabetes were identified as the major risk factors for nosocomial infections among hemodialysis patients.

Conclusion

The results of this review indicate an information gap and potential benefits of additional preventive measures to further reduce the risk of infections in hemodialysis population. Moreover, several patient-related and facility-related risk factors were consistently observed in the studies included in this review, which require optimal control measures.

The Heat Stability of Hepatitis B Virus: A Chronological Review From Human Volunteers and Chimpanzees to Cell Culture Model Systems

During the World War II jaundice and hepatitis in the US army were observed after vaccination with the yellow fever vaccine containing human plasma for stabilization. This led to first heat experiments with volunteers without knowledge of the causative agents. Finally, experiments of human serum with volunteers and chimpanzees led to the conclusion that the hepatitis B virus (HBV) which had been identified as the responsible agent of the contamination of the vaccine, could not be inactivated at 98°C after 1 min, whereas 2 min in two chimpanzees were enough. Meanwhile, a cell culture system became available showing that 2 min exposure time is not enough depending on the virus strain used whereas 5 min means complete inactivation of HBV. The great stability of the blood-borne HBV was also of interest in hospital hygiene due to the use of moist heat for disinfection of heat-stable medical devices in washer-disinfectants. The requirements for washer-disinfectors and the parameters describing disinfection with moist heat are defined in the EN ISO 15883. In this standard, the efficacy of this thermal disinfection is described by the A₀ value. For heat-resistant viruses a higher A₀ = 3,000 is often recommended including semi-critical instruments that undergo thermal disinfection and no final sterilization. All experiments including volunteers, chimpanzees and now cell culture were performed with greater A₀ values than 3,000. Therefore, an A₀ value of 3,000 e.g., being reached by 90°C and 5 min in washer-disinfectants, can easily elevated to 6,000 by prolongation of the exposure time to 10 min. In contrast to the different laboratory experiments with high virus titers it should be considered that in practice the necessary cleaning step upfront will help to reduce virus load and then protect the personnel in the medical area.

Genetic Diversity of the Hepatitis B Virus Subgenotypes in Brazil

Hepatitis B virus (HBV) subgenotypes may be related to clinical outcomes and response to antiviral therapy. Most Brazilian studies on HBV subgenotypes are restricted to some regions and to specific population groups. Here, we provide an insight about genetic diversity of HBV subgenotypes in 321 serum samples from all five geographical regions, providing a representative overview of their circulation among chronic carriers. Overall, HBV/A1 was the most prevalent subgenotype, being found as the major one in all regions except in South Brazil. Among HBV/D samples, subgenotype D3 was the most prevalent, found in 51.5%, followed by D2 (27.3%) and D4 (21.2%). D2 and D3 were the most prevalent subgenotypes in South region, with high similarity with European strains. D4 was found in North and Northeast region and clustered with strains from Cape Verde and India. For HBV/F, the most frequent subgenotype was F2 (84.1%), followed by F4 (10.1%) and F1 (5.8%), closely related with strains from Venezuela, Argentina and Chile, respectively. Phylogeographic analyses were performed using an HBV full-length genome obtained from samples infected with genotypes rarely found in Brazil (B, C, and E). According to Bayesian inference, HBV/B2 and HBV/C2 were probably introduced in Brazil through China, and HBV/E from Guinea, all of them mostly linked to recent events of human migration. In conclusion, this study provided a comprehensive overview of the current circulation of HBV subgenotypes in Brazil. Our findings might contribute to a better understand of the dynamics of viral variants, to establish a permanent molecular surveillance on the introduction and dispersion patterns of new strains and, thus, to support public policies to control HBV dissemination in Brazil.

High rate of occult hepatitis B virus infection in hemodialysis units of KwaZulu-Natal, South Africa

Occult hepatitis B virus (HBV) infection (OBI) is defined as the presence of HBV DNA in the liver with or without detectable HBV DNA in the serum of individuals testing HBV surface antigen (HBsAg) negative using currently available assays. The prevalence of OBI among patients receiving hemodialysis (HD) treatment remains poorly characterized in South Africa despite the high prevalence of HBV. We sought to determine the prevalence of OBI in HD units in tertiary hospitals of KwaZulu-Natal and to characterize the HBV S gene mutations potentially responsible for OBI. A cross-sectional descriptive study of residual diagnostic plasma samples from 85 HBsAg-negative patients receiving HD treatment was included. The PreS/S gene was amplified with a nested HBV polymerase chain reaction for downstream next-generation sequencing, to determine the viral genotype and identify S gene mutations associated with OBI. Nine of the 85 samples had OBI, based on detectable HBV DNA. The point prevalence of OBI was 10.6% (95% control interval: 5.5%-19.1%). Phylogenetic analysis of the samples with OBI showed that all belonged to genotype A. Three (~33%) samples had mutations in the major hydrophilic region (MHR) within the S gene, three (~33%) had mutations within the S gene but outside the MHR, whilst the remaining three had no mutations observed. The prevalence of OBI in HBsAg-negative patients undergoing HD was 10.6%, suggesting that OBI is a clinically significant problem in patients with HD in this region. The screening methods for HBV infection need to be revised to include nucleic acid testing.

A case-control study of risk factors for hepatitis B infection: A regional report among Isfahanian adults

Background:

Hepatitis B is one of the major causes of mortality among viral diseases. To reduce morbidity rate and increase knowledge of people about potential risk factors, the aim of this study was to determine the prevalence of hepatitis B among the general population and the risk factors associated with hepatitis B virus (HBV) infection in Isfahan, Iran.

Materials and Methods:

In a case–control study, 314 HBV-infected patients and 557 healthy participants were recruited. Data on demographics, immunization history, medical history, family medical history, life history, therapeutic factors, and behavioral risk factors were collected through a standard checklist. Chi-square and logistic regression were used for univariate and multivariable analyses.

Results:

Our results showed that among sociodemographic variables, higher age, being male, lower economic status, and lower educational attainments increased the risk of affecting by HBV (odds ratio [OR] >1, P < 0.001); furthermore, Iranian and no immigrant people showed higher significant risk of being affected by HBV. Multivariable logistic regression showed among medical, blood, and behavioral risk factors, family history of hepatitis (OR: 10.56; 95% confidence interval [CI]: 4.56–24.86), dental treatment history (OR: 4.30; 95% CI: 1.41–13.10), and hospitalization (OR: 2.94; 95% CI: 1.72–5.00).

Conclusion:

Our results demonstrated that there are still several risk factors for hepatitis B surface antigen infection among the Iranian adult population. Immunization programs should continue and focus on high-risk adults, and interventions should be directed toward to reduce risk factors associated with hepatitis B.

High Prevalence of Hepatitis B Subgenotype D4 in Northeast Brazil: an Ancient Relic from African Continent?

INTRODUCTION

Hepatitis B virus (HBV) infection leads to a chronic liver disease that is distributed worldwide. The characterization of HBV into genotypes/subgenotypes is not only a mere procedure for distinguishing different HBV strains around the world because determining their geographic distribution is crucial to understanding their spread across the world.

MATERIAL AND METHODS

We characterized different HBV genotypes and subgenotypes in five municipalities located in northeastern Maranhão, in the Brazilian north Atlantic coast. 92 HBsAg-positive individuals were submitted to PCR (polymerase chain reaction). Fifty samples were sequenced using automated Sanger sequencing and classified by phylogenetic methods.

RESULTS

Subgenotypes D4 and A1 were found in 42 (84%) and eight (16%) samples, respectively. To our knowledge, this is the first study to describe a high frequency of subgenotype D4 in any population. Subgenotype A1 is frequently found across Brazil, but D4 has been rarely detected and only in a few Brazilian states. This study shows the characterization of HBV subgenotypes from a population based study in the state of Maranhão, particularly in populations that do not have frequent contact with populations from other regions of the world.

CONCLUSION

Our findings showed a HBV subgenotype profile that probably reflect the viruses that were brought with the slave trade from Africa to Maranhão. This study also reinforces the need to evaluate the status of HBV dispersion not only in large urban centers, but also in the hinterland, to enable the implementation of effective control and treatment measures.

Hepatitis B Virus Infection in the Dialysis Population: Current Perspectives

One of the major advances in the management of patients on regular dialysis has been the control of the spread of hepatitis B virus (HBV) infection in dialysis units. The rate of HBsAg positive patients on regular dialysis in the developed world is currently low, but outbreaks of HBV continue to occur. The diffusion of HBV in dialysis units in developing countries is higher, although available information is not abundant. There are limited data on the natural history of HBV in the dialysis population; they support a detrimental effect of HBV on survival in dialysis patients. The HBV viral load in HbsAg-positive dialysis patients appears low and stable over time and numerous mechanisms have been posited to explain it. Several assays for detecting HBV DNA in serum are available but they should not be used for purposes of routine screening within dialysis units. The epidemiology and clinical significance of occult HBV infection in the dialysis population needs to be addressed adequately - this remains an area of active research. Recent recommendations for the management of HBsAg chronic carriers on maintenance dialysis have been issued. No controlled trials for the treatment of hepatitis B with either interferon or lamivudine in dialysis patients are currently available.

The Management of Viral Hepatitis in CKD Patients: An Unresolved Problem

Chronic kidney disease (CKD) patients in dialysis (HD) show peculiar, atypical features of clinical presentation and diseases (cardiovascular, metabolic, hematologic). This is also true for viral hepatitis infections, for which CKD patients represent an important risk group. In the past, hepatitis B virus (HBV) was the major cause of viral hepatitis in end-stage renal disease (ESRD). However, the introduction of a rigorous infection-control strategy, routine screening of patients and staff for hepatitis B serologic markers, vaccination of susceptible patients and staff, use of separate rooms and dedicated machines for HD of HbsAg-positive patients have all led to a decline in the spread of HBV infection in dialysis. Despite the prevalence of the antibody-hepatitis C virus (HCV), there has been a marked decrease in HD patients; after the introduction of routine screening for HCV and the use of erythropoietin, its occurrence ranges from 5% to 25% in the United States, with a prevalence of 6.8% in Europe. In CKD and in HD patients, the presence of HBV and HCV is an independent and significant risk factor for death and this risk may be at least partially attributed to chronic liver disease with its attendant complications. Liver disease can progress with modest hepatic inflammation and prominent fibrosis; the natural history of viral hepatitis in these patients is dependent on the immune dysfunction typical of kidney disease. Despite recent advances in antiviral therapy, there are still many uncertainties in regards to the efficacy and long-term outcomes of treatment with antiviral agents.

Cross-Sectional Study to Determine the Prevalence of Hepatitis B and C Virus Infection in High Risk Groups in the Northeast Region of Brazil

Background: HBV (Hepatitis B Virus) and HCV (Hepatitis C Virus) infections are more prevalent in vulnerable populations than the general population. The objective of this study was to investigate the prevalence of HBV and HCV infection in HIV-positive patients (GI), chronic renal failure (CRF) patients (GII) and coagulation disorder individuals (GIII). Methods: A cross-sectional study was conducted from June 2014 to March 2015. Serum samples were tested for markers of hepatitis B and C by enzyme-linked immunosorbent assay (ELISA). Sociodemographic, epidemiological, clinical and laboratory data and accompanying statistical analyses were performed using Epi Info™ 7. Results: A total of 348 individuals were recruited, i.e., 154 HIV-positive, 143 CRF and 51 coagulopathy patients. Among them, more than 66% were men, and the predominant age group was 26–35 years in GI and 56–65 years in GIII. Most patients had more than 8 years of education (66.2% in GI, 60.6% in GIII and 46.1% in GII), with a family income between 100–400 dollars in more than 48% of patients. The prevalence of the HBsAg marker was 3.9%, 7% and 3.9%, total anti-HBc was 28.6%, 55.9% and 31.4%, and anti-HCV was 1.3%, 12.6% and 47% for GI, GII and GIII, respectively. However, the prevalence of anti-HBs was greater than 70% in all groups. Conclusions: This study shows a high prevalence of HBV and HCV among specific groups compared to the general population. Factors such as age, income, number of sexual partners, sexually transmitted disease burden, blood transfusion history or blood products and blood transfusions before 1994 were associated with a higher prevalence for these infections.

Hepatitis B status in hemodialysis patients

ABSTRACT BACKGROUND: Patients on chronic dialysis present a high prevalence of hepatitis B virus infection. Despite infection-control practices, surveillance of serological markers, and hepatitis B vaccination, there are still outbreaks of the disease in dialysis centers. OBJECTIVE: This study aims to assess the serologic and vaccination status for hepatitis B in hemodialysis patients. METHODS: This cross-sectional study assessed serologic markers and hepatitis B vaccination status of chronic kidney disease patients on regular dialysis program in São Carlos, SP, Brazil. Patients without information about hepatitis B status (anti-HBc, HBsAg and anti-HBs) were referred for testing. Individuals with uncertain or incomplete immunization status and without serological conversion (anti-HBs <10mIU/mL) were referred to vaccination, with adverse effects monitored. RESULTS: The study included 130 from a total of 181 dialysis patients. The majority were male (63.8%), mean age 53.9 years. All patients were already screened and negative for HBsAg, and 73.8% were vaccinated against hepatitis B (59.2% complete and 14.6% incomplete schedule), with a seroconversion rate of 75.3%. Only 11 (8.5%) patients had prior dosage of anti-HBc (negative). Among the 47 patients referred for anti-HBc testing, four were anti-HBc positive and one indeterminate. Of the total of patients referred to immunization, 34 have actually received HBV vaccine; among them five had mild adverse effects. CONCLUSION: Despite the benefit of dosing of anti-HBc and anti-HBs before admission to dialysis, economic constraints have reduced the screening to only HBsAg. Since occult HBV infection has already been demonstrated in hemodialysis patients, the measure of anti-HBc should be encouraged.

Nationwide overview of the distribution of hepatitis B virus genotypes in Brazil: a 1000-sample multicentre study

The influence of hepatitis B virus (HBV) genotypes in the natural history of the disease and its response to antiviral treatment have been addressed in many studies. In Brazil, studies on HBV genotype circulation have been restricted to specific population groups and states. Here, we have conducted a nationwide multicentre study with an unprecedented sample size representing all Brazilian regions in an effort to better understand the viral variants of HBV circulating among chronic carriers. Seven HBV genotypes were found circulating in Brazil. Overall, HBV/A was the most prevalent, identified in 589 (58.7 %) samples, followed by HBV/D (23.4 %) and HBV/F (11.3 %). Genotypes E, G, C and B were found in a minor proportion. The distribution of the genotypes differed markedly from the north to the south of the country. While HBV/A was the most prevalent in the North (71.6 %) and Northeast (65.0 %) regions, HBV/D was found in 78.9 % of the specimens analysed in the South region. HBV/F was the second most prevalent genotype in the Northeast region (23.5 %). It was detected in low proportions (7 to 10 %) in the North, Central-West and Southeast regions, and in only one sample in the South region. HBV/E was detected in all regions except in the South, while monoinfection with HBV/G was found countrywide, with the exception of Central-West states. Our sampling covered 24 of the 26 Brazilian states and the Federal District and is the first report of genotype distribution in seven states. This nationwide study provides the most complete overview of HBV genotype distribution in Brazil to date and reflects the origin and plurality of the Brazilian population.

An in-house real-time polymerase chain reaction: standardisation and comparison with the Cobas Amplicor HBV monitor and Cobas AmpliPrep/Cobas TaqMan HBV tests for the quantification of hepatitis B virus DNA

This study aimed to standardise an in-house real-time polymerase chain reaction (rtPCR) to allow quantification of hepatitis B virus (HBV) DNA in serum or plasma samples, and to compare this method with two commercial assays, the Cobas Amplicor HBV monitor and the Cobas AmpliPrep/Cobas TaqMan HBV test. Samples from 397 patients from the state of São Paulo were analysed by all three methods. Fifty-two samples were from patients who were human immunodeficiency virus and hepatitis C virus positive, but HBV negative. Genotypes were characterised, and the viral load was measure in each sample. The in-house rtPCR showed an excellent success rate compared with commercial tests; inter-assay and intra-assay coefficients correlated with commercial tests (r = 0.96 and r = 0.913, p < 0.001) and the in-house test showed no genotype-dependent differences in detection and quantification rates. The in-house assay tested in this study could be used for screening and quantifying HBV DNA in order to monitor patients during therapy.

Hepatitis B Virus Genotype D Isolates Circulating in Chapecó, Southern Brazil, Originate from Italy

Hepatitis B virus genotype A1 (HBV/A1), of African origin, is the most prevalent genotype in Brazil, while HBV/F predominates in the other South American countries. However, HBV/D is the most common in the three states of southern Brazil, where ‘islands’ of elevated prevalence, as Chapecó and other cities, have been described. In this study, 202 HBV chronic carriers attending in 2013 the viral hepatitis ambulatory of Chapecó, were investigated. In comparison with previous studies performed in the same ambulatory, a rapid aging of the HBV infected population was observed (mean age of the newly diagnosed patients increasing from 29.9 ± 10.3 years in 1996 to 44.4 ± 13.3 years in 2013), probably due to a singular vaccination schedule at Chapecó that included not only children but also adolescents. Phylogenetic and BLAST analyses (S region) classified 91 HBV isolates into genotypes A (n = 3) and D (n = 88). The majority of HBV/D isolates were closely related to D3 sequences. To understand the reasons for the absence or near absence of genotypes A and F, and how HBV/D was introduced in the south of Brazil, HBV/D infected patients were inquired about their genealogical and geographical origins. Forty-three (52%) patients have their four grandparents of Italian origin, vs. seven (8%) who have their four grandparents of Brazilian origin. At all, 65 out of 83 (78%) patients had at least one grandparent originating from Italy. Taking into consideration the fact that Italy is one of the few countries where subgenotype D3 is predominant, the results strongly suggested that HBV/D was introduced in Brazil through Italian immigration which culminated between 1870 and 1920.

Hepatitis B virus genotypes and mutations in the basal core promoter and pre-core/core in chronically infected patients in southern Brazil: a cross-sectional study of HBV genotypes and mutations in chronic carriers

INTRODUCTION

In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil.

METHODS

Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed.

RESULTS

Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher prevalence of the G1862T mutation and the presence of a cytosine at position 1858.

CONCLUSIONS

HBV genotype D (D3) is predominant in HBV chronic carriers from southern Brazil. The presence of mutations in the BCP and precore/core region was correlated with the HBV genotype and HBeAg negative status.

Viral hepatitis in hemodialysis: An update

Hepatitis outbreaks in hemodialysis (HD) patients and staff were reported in the late 1960s, and a number of hepatotropic viruses transmitted by blood and other body fluids have been identified. Hepatitis B virus (HBV) was the first significant hepatotropic virus to be identified in HD centers. HBV infection has been effectively controlled by active vaccination, screening of blood donors, the use of erythropoietin and segregation of HBV carriers. Hepatitis delta virus is a defective virus that can only infect HBV-positive individuals. Hepatitis C virus (HCV) is the most significant cause of non-A, non-B hepatitis and is mainly transmitted by blood transfusion. The introduction in 1990 of routine screening of blood donors for HCV contributed significantly to the control of HCV transmission. An effective HCV vaccine remains an unsolved challenge; however, pegylation of interferon-alfa has made it possible to treat HCV-positive dialysis patients. Unexplained sporadic outbreaks of hepatitis by the mid-1990s prompted the discovery of hepatitis G virus, hepatitis GB virus C and the TT virus. The vigilant observation of guidelines on universal precaution and regular virologic testing are the cornerstones of the effective control of chronic hepatitis in the setting of HD. Major recent advances in the viral diagnosis technology and the development of new oral, direct-acting antiviral agents allow early diagnosis and better therapeutic response. The current update will review the recent developments, controversies and new treatment of viral hepatitis in HD patients.

Identification of hepatitis B virus genotypes in the state of São Paulo

Objective: the aim of this study was to identify HBV genotypes in serum samples from patients from the state of São Paulo, received by the viral hepatitis laboratory, at the Virology Centre of Instituto Adolfo Lutz, from various municipalities. Methods: a total of 94 serum samples were randomly analyzed. Genotyping was performed using nested PCR for amplification of S and Pol regions from viral genome. Genotypes were identified comparing the sequences obtained with the sequences deposited in GenBank. Results: we were able to determine the genotype of 91 (97%) samples, as follows: genotype A (55.3%), D (32%), F (5.3%), C (3.2%) and G (1%). There are few data on the epidemiology of genotype G. This genotype has been detected in restricted areas around the world. Frequently, the genotype G infection occurs in HIV-positive male patients. In our case, the sample identified as G was also positive for HIV but in a female patient, which is an uncommon finding in the scientific literature. Conclusion: in this work, we identified the most frequent genotypes in São Paulo as well as the genotype G, rare among the genotypes found in our environment.

Prevalence of occult HBV among hemodialysis patients in two districts in the northern part of the West Bank, Palestine

Occult hepatitis B infection is the case with undetectable HBsAg, but positive for HBV DNA in liver tissue and/or serum. Occult hepatitis B infection among hemodialysis patients in Palestine has been understudied. In this study, 148 hemodialysis patients from 2 northern districts in Palestine, Jenin (89) and Tulkarem (59), were investigated for occult hepatitis B, HBV, HCV infections with related risk factors. ELISA and PCR were used for the detection of anti-HBc and viral DNA, respectively. The overall prevalence of occult hepatitis B infection among the study group was 12.5% (16/128). Occult hepatitis B infection is more prevalent among males with most cases (15/16) from Jenin District. About one-third (42/132) of the hemodialysis patients were anti-HBc positive. Approximately 27% of the hemodialysis patients were infected with HCV. Around 20% (28/140) were positive for HBV DNA, but only 8.2% (12/146) of the hemodialysis patients were positive for HBsAg. The comparison between hemodialysis patients with occult hepatitis B infection and those without occult hepatitis B infection for selected risk factors and parameters as liver Enzyme, age, sex, HCV infection, blood transfusion, kidney transplant, anti-HBc, and vaccination showed no statistical significance between both categories. Duration of hemodialysis significantly affected the rate of HCV infection. HCV is significantly higher in hemodialysis patients with both Diabetes mellitus and hypertension. The prevalence of occult hepatitis B infection among hemodialysis patients is high; requiring stringent control policies. HBsAg assay is insufficient test for accurate diagnosis of HBV infection among hemodialysis patients.

Melting curve analysis for the screening of hepatitis B virus genotypes A, D and F in patients from a general hospital in southern Brazil

CONTEXT

Hepatitis B virus (HBV) can cause fulminant hepatitis, cirrhosis and hepatocellular carcinoma, and is one of the most common causes of acute and chronic liver failure. The genetic variants of HBV can be decisive for the evolution of these diseases as well as for the election of therapy.

OBJECTIVES

The aim of this study was to evaluate and standardize an in house methodology based on the analysis of the melting curve polymerase chain reaction (PCR) of real-time (qPCR) to screen for genotypes A, D and F of HBV in patients from a hospital in Rio Grande do Sul, Brazil.

METHODS

We evaluated 104 patients presumably with HBV chronic infection. Viral DNA was extracted from plasma and viral genotypes and different mutations were determined using PCR-based protocols.

RESULTS

A PCR-based methodology was standardized for the analysis of genotypes A, D and F of HBV. The technique was based in a nested PCR with the final step consisting of a multiplex real-time PCR, using the melting curve as a tool for the differentiation of fragments. A higher frequency of genotype D (44.4%), followed by genotype A (22.2%) and genotype F (3.7%) was observed.

CONCLUSION

The standardized assay, a nested PCR-multiplex qPCR using specific primers, provides a rapid and accurate method for the differentiation of HBV genotypes that are more frequent in Southern Brazil - A, D and F. This method can be applied in the clinical practice.

Is hepatitis B-virucidal validation of biocides possible with the use of surrogates?

The hepatitis B virus (HBV) is considered to be a major public health problem worldwide, and a significant number of reports on nosocomial outbreaks of HBV infections have been reported. Prevention of indirect HBV transmission by contaminated objects is only possible through the use of infection-control principles, including the use of chemical biocides, which are proven to render the virus non-infectious. The virucidal activity of biocides against HBV cannot be predicted; therefore, validation of the virucidal action of disinfectants against HBV is essential. However, feasible HBV infectivity assays have not yet been established. Thus, surrogate models have been proposed for testing the efficacy of biocides against HBV. Most of these assays do not correlate with HBV infectivity. Currently, the most promising and feasible assay is the use of the taxonomically related duck hepatitis B virus (DHBV), which belongs to the same Hepadnaviridae virus family. This paper reviews the application of DHBV, which can be propagated in vitro in primary duck embryonic hepatocytes, for the testing of biocides and describes why this model can be used as reliable method to evaluate disinfectants for efficacy against HBV. The susceptibility levels of important biocides, which are often used as ingredients for commercially available disinfectants, are also described.

Intrafamilial spread of hepatitis B virus in Guilan Province-North of Iran

The aim of the present study was to determine the intrafamilial spread of HBV in the family members of patients with Hepatitis B in Guilan Province, North of Iran. In a descriptive-comparative study, 156 patients with Hepatitis B, 415 family members of the index cases and 599 age and gender matched people as a control group were enrolled. Blood samples were taken from the participants and were checked for HBs Ag, HBC Ab, HBs Ab, and HBV DNA. Totally 44 (10.6%) of family members and only 1 (0.2%) of control group were HBs Ag positive (P=0.0001, OR=70.92). The overall prevalence in members of the original family was 5.3% (1.2% of the mothers, 2.2% of the brothers, 1.9% of the sisters), in sexual partners it was 1.4%, in offsprings it was 2.4% and in other households it was 1.4%. The mean age of HBs Ag positive family members was 35.3 ± 12.9 years old. Among them 27 (61.4%) were female. Only 8 (18.2%) of all HBsAg-positive reported previous HBV vaccination but just one person had the vaccine titer checked. The present survey indicates that there is a significant difference in the prevalence of Hepatitis B in the general population and family members of Hepatitis B patients and this is an evidence for horizontal transmission of HBV in household contacts.

Hepatitis B virus in the State of Alagoas, Brazil: genotypes characterization and mutations of the precore and basal core promoter regions

The aims of this study were to investigate the genotypes of hepatitis B virus and to identify the precore G1896A and basal core promoter A1762T/G1764A mutations in HBsAg and anti-HBc-positive patients. Eighty-three asymptomatic individuals, three with acute hepatitis B and 33 with chronic hepatitis B referred to viral hepatitis centers in the State of Alagoas, Brazil were analyzed according to their viral load, HBeAg/anti-HBe profile and alanine aminotransferase serum level. The genotypes identified were: A (92.5%), C (5%), D (1.25%) and F (1.25%). The precore mutation was detected in 3.8% of sequences and basal core promoter mutation in 52.4%. These were identified in 45.45% of the asymptomatic individuals and 54.55% of the patients with chronic hepatitis, irrespective of viral load and alanine aminotransferase serum level. In genotype C, only the basal core promoter mutation was identified and no mutations were identified in genotypes D and F.

Phylogenetic analysis and subgenotypic distribution of the hepatitis B virus in Recife, Brazil

The analysis of the genomes of the hepatitis B virus in human hosts identifies phylogenetic variants called viral genotypes. Indeed, clinical and epidemiological observations suggest that differences in viral genotypes lead to distinct biological and clinical behaviors. The aim of this study was to evaluate the subgenotypic distribution and to conduct a phylogenetic analysis by Bayesian method of the hepatitis B virus (HBV) in patients from Recife, Brazil. From July 2009 to December 2010, 60 HBV infected patients were examined, 39 (65%) were males, whose mean age was 50years old. 33 (55%) were genotyped by obtaining and amplifying a 1306bp fragment comprising part of the DNA polymerase and the surface antigen of the HBV. The sequencing was performed on an ABI 3500 Automatic Sequencer and the consensus sequences were obtained by aligning both the sequenced strands (clockwise and anti-clockwise) using SEQUENCHER software. Phylogenetic analysis was conducted using the Markov Chain Monte Carlo simulation implemented by Bayesian evolutionary method by sampling trees. The following subgenotypic distribution was observed: A1 (79%), F2a (12%), A2 (6%) and F4 (3%) as was that those identified as subgenotype A1 were in the same cluster in the phylogenetic tree. In this study, the majority of patients presented the A1 subgenotype from the same viral strain. As per the distribution in the phylogenetic tree by Bayesian method, possibly this subgenotype was in the genetic make-up of Africans brought in centuries past to Brazil as slaves.

Occult hepatitis B virus infection in hemodialysis patients in Recife, State of Pernambuco, Brazil

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.

Molecular characterization of the hepatitis B virus in autochthonous and endogenous populations in the Western Brazilian Amazon

INTRODUCTION

Hepatitis B virus (HBV) infection is a serious public health issue worldwide. Hepatitis B virus is classified into eight genotypes, varying from A to H, with distinct geographical distributions. In Brazil, the most frequent genotypes are A, D, and F.

METHODS

This study aimed to characterize the HBV genotypes in cases of hepatitis B virus and hepatitis D virus (HDV) co-infections in an endemic area in the Western Brazilian Amazon. We analyzed 86 serum samples reactive for HBsAg from indigenous and non-indigenous populations obtained from previous serological surveys.

RESULTS

Of the 86 reactive serum samples, 39 were found to be HBV-DNA-positive by semi-nested PCR. The genotypes were established by sequencing the amplified S gene region. We obtained 20 sequences classified into three genotypes: A, D, and F. Genotype A was the most frequent (60%), followed by D (35%) and F (5%).

CONCLUSIONS

The distribution of the HBV genotypes reflected the pattern of historical occupation of the region.

Improving hepatitis B vaccine efficacy in end-stage renal diseases patients and role of adjuvants

Hepatitis B virus (HBV) infection is a serious global health problem.The prevalence of viral hepatitis is higher in dialysis patients than in the general population because of the opportunity for exposure during the dialysis procedure. Immunization is the most effective way to prevent transmission of hepatitis B virus (HBV) and hence the development of acute or chronic hepatitis B. It is well established that patients with end-stage renal disease including dialysis-dependent patients, have an impaired immune response to hepatitis B vaccine. End stage renal diseases (ESRD) patients have lower seroconversion rates compared with the subjects with intact renal function. Moreover, even after the completion of vaccination schedule anti-hepatitis B (anti-HBs) titers of responder dialysis, patients are low and decline logarithmically with time. The impaired efficacy of HBV vaccine in patients with ESRD has been attributed to numerous factors such as immune compromise because of uremia and some other factors. One approach to improve the immunogenicity of existing HBV vaccines is adjuvantation, and it's very important to find more effective adjutants for improving HBV vaccine efficacy. In this paper we have a brief review on recently known new ways for improving HBV vaccine efficacy.

Hepatitis B virus genotypes from European origin explains the high endemicity found in some areas from southern Brazil

Southern Brazil is considered an area of low Hepatitis B endemicity, but some areas of higher endemicity have been described in the Southwest of Paraná and Santa Catarina states. The aim of this study was to evaluate viral genotypes circulating throughout Paraná state. PCR amplification and partial sequencing of the S gene was carried out in 228 samples from HBsAg positive candidate blood donors. Samples have been collected in seven different counties (Cascavel, Curitiba, Foz do Iguaçu, Francisco Beltrão, Maringá, Londrina and Paranaguá). The most common HBV genotype in Paraná state was D (82.9%; 189/228), followed by A (14.1%; 32/228). Genotypes F (1.3%; 3/228), C (1.3%; 3/228) and H (0.4%; 1/228) were also found. Distribution of genotypes was different in the studied counties, but genotype D was the most frequent in all of them. In Francisco Beltrão, all studied samples belonged to genotype D. The high prevalence of HBV genotype D in South of Brazil is explained by the intense migration of settlers from Europeans countries. Subgenotypes A1 and A2 were identified circulating in all cities where HBV/A was found. As observed in other areas of Brazil, HBV/A1 is more frequent than the HBV/A2 in Paraná state and its presence was significantly larger in black and mulatto individuals. Genotype C was found only in individuals with Asian ancestry from Londrina and Maringá. Most HBV/F sequences identified in this study were classified as subgenotype F2a that was previously described in Brazil. The sole case of subgenotype F4 was from Foz do Iguaçu city, near to Northern Argentina, where F4 is highly prevalent. The single genotype H sample was from Curitiba. This is the first case of this genotype described in Brazil. Further studies should be carried out to determine if more genotype H samples can be found in other populations from Brazil.

Prevalence of hepatitis B in haemodialysis nursing staff in Athens

BACKGROUND

Healthcare workers are at high risk of acquiring hepatitis B and particularly haemodialysis staff. The aim of the study was to examine the prevalence of hepatitis B markers in haemodialysis nurses and to explore the determinants of the infection.

PATIENTS AND METHODS

Two hundred and sixteen haemodialysis nurses from 20 haemodialysis units in Athens completed an anonymous questionnaire, their blood samples were taken and tested for hepatitis B virus (HBV) markers.

RESULTS

The prevalence of positive HBsAg among nurses was 0.5%. Anti-HBc positivity due to past exposure to HBV was 12.5%. A total of 87.5% of the participants had immunity to HBV. Multivariate analysis demonstrated that previous exposure to HBV was related positively with the age of the haemodialysis nursing staff [odd ratios (OR): 1.115, 95% CI: 1.014-1.226, P = 0.025].

CONCLUSION

The prevalence of HBV in the haemodialysis nursing staff in Athens is low, the vaccination coverage and the immunity to HBV are high in comparison to previous reports.

Comparing immune response of intradermal low dose versus intramuscular high dose of hepatitis B vaccination in hemodialysis patients

BACKGROUND

Hepatitis B is the most important cause of cirrhosis in developing countries. Hemodialysis patients are susceptible to infection due to repeated contact with dialysis machines and blood products. The aim of this study was to compare the efficacy of intradermal low dose with intramuscular high dose hepatitis B vaccination in hemodialysis patients.

METHODS

In a cross-sectional study on 24 hemodialysis patients that not responded to conventional method of vaccination in this center (double dose in 0, 1 and 6 months) and have antibody titer less than 10 mu/ml were enrolled to intramuscular or intradermal group, randomly. In intradermal (ID) group 10 μg (0.5 ml) recombinant vaccine, every 2 weeks to 6 months and in intramuscular (IM) group 40 μg (2 ml) at 0, 1, 2, and 6 months were prescribed and antibody titer were checked after 1 and 3 months of the end of vaccination.

RESULTS

Mean HBS antibody titer in patients was 4.4 ± 3.1 mu/ml at the beginning of study (minimum: 1.1 mu/ml and maximum: 9.2 mu/ml) and after 1 month and 3 months, mean HBS antibody were 190.4 ± 59 and 223.3 ± 83.9, respectively (p < 0.001). After one month, in intradermal and intramuscular groups, mean HBS antibody was 198.8 ± 75.6 mu/ml and 181.2 ± 61.8 mu/ml, respectively (p = 0.5) and after 3 months it was 230 ± 76 mu/ml and 216.2 ± 94.3 mu/ml, respectively (p = 0.83).

CONCLUSIONS

Antibody titer was high (> 50 mu/ml) in two groups after 1 and 3 months of vaccination and no significant difference was found between the 2 groups. Therefore, two methods of vaccination (high dose IM and low dose SC) are equally effective and the selection of vaccination method is based on health policy.

Characterization of hepatitis B virus (HBV) genotypes in patients from Rondônia, Brazil

BACKGROUND

Hepatitis B virus (HBV) can be classified into nine genotypes (A-I) defined by sequence divergence of more than 8% based on the complete genome. This study aims to identify the genotypic distribution of HBV in 40 HBsAg-positive patients from Rondônia, Brazil. A fragment of 1306 bp partially comprising surface and polymerase overlapping genes was amplified by PCR. Amplified DNA was purified and sequenced. Amplified DNA was purified and sequenced on an ABI PRISM® 377 Automatic Sequencer (Applied Biosystems, Foster City, CA, USA). The obtained sequences were aligned with reference sequences obtained from the GenBank using Clustal X software and then edited with Se-Al software. Phylogenetic analyses were conducted by the Markov Chain Monte Carlo (MCMC) approach using BEAST v.1.5.3.

RESULTS

The subgenotypes distribution was A1 (37.1%), D3 (22.8%), F2a (20.0%), D4 (17.1%) and D2 (2.8%).

CONCLUSIONS

These results for the first HBV genotypic characterization in Rondônia state are consistent with other studies in Brazil, showing the presence of several HBV genotypes that reflects the mixed origin of the population, involving descendants from Native Americans, Europeans, and Africans.

Review article: Hepatitis B and dialysis

The incidence of hepatitis B virus (HBV) infection in dialysis populations has declined over recent decades, largely because of improvements in infection control and widespread implementation of HBV vaccination. Regardless, outbreaks of infection continue to occur in dialysis units, and prevalence rates remain unacceptably high. For a variety of reasons, dialysis patients are at increased risk of acquiring HBV. They also demonstrate different disease manifestations compared with healthy individuals and are more likely to progress to chronic carriage. This paper will review the epidemiology, modes of transmission and diagnosis of HBV in this population. Prevention and treatment will be discussed, with a specific focus on strategies to improve vaccination response, new therapeutic options and selection of patients for therapy.

Hepatitis C infection in hemodialysis patients in Iran: a systematic review

Hemodialysis (HD) patients are recognized as one of the high-risk groups for hepatitis C virus (HCV) infection. The prevalence of HCV infection varies widely between 5.5% and 24% among different Iranian populations. Preventive programs for reducing HCV infection prevalence in these patients require accurate information. In the present study, we estimated HCV infection prevalence in Iranian HD patients. In this systematic review, we collected all published and unpublished documents related to HCV infection prevalence in Iranian HD patients from April 2001 to March 2008. We selected descriptive/analytic cross-sectional studies/surveys that have sufficiently declared objectives, a proper sampling method with identical and valid measurement instruments for all study subjects, and proper analysis methods regarding sampling design and demographic adjustments. We used a meta-analysis method to calculate nationwide prevalence estimation. Eighteen studies from 12 provinces (consisting 49.02% of the Iranian total population) reported the prevalence of HCV infection in Iranian HD patients. The HCV infection prevalence in Iranian HD patients is 7.61% (95% confidence interval: 6.06-9.16%) with the recombinant immunoblot assay method. Iran is among countries with low HCV infection prevalence in HD patients.

Phylogenetic analysis of hepatitis B virus full-length genomes reveals evidence for a large nosocomial outbreak in Belgium

BACKGROUND

Hepatitis B virus (HBV) is primarily transmitted from mother to child, by sexual contact, intravenous drug abuse, or unsafe health care-related injection practices. Despite increased safety efforts, nosocomial acquired hepatitis B infection remains problematic.

OBJECTIVES

A large HBV outbreak was investigated comprising 36 patients with acute HBV infection in a primary care physician's practice.

STUDY DESIGN

In a retrospective study (2003-2008), 36 serum samples from patients with acute HBV infection were collected. They had received several injections by the same physician at least 3 months before the onset of clinical symptoms. As a control group, sera were collected from HBV patients from other physicians from the same province. Full-length HBV genomes were amplified and were phylogenetically analysed.

RESULTS

HBV complete genomes of 32 patients were successfully amplified and sequenced, and clustered together with the reference genotype A, subgenotype A2 strains. We also analysed 26 control HBV genotype A samples. All 32 HBV strains from the patient group clustered in a monophyletic branch with a bootstrap value of 100, whereas the control samples branched separately in another clade. The genetic distance value showed small differences within the patients group, whereas the rate within the control group was seven times higher. These observations confirm that the source of transmission was clearly different in both groups.

CONCLUSION

Maximum likelihood analysis and genetic distance calculations based on the full-length genomes of HBV strains isolated from patients and controls provided strong evidence for a common nosocomial source of infection for all 32 patient cases.

Determinant roles of environmental contamination and noncompliance with standard precautions in the risk of hepatitis C virus transmission in a hemodialysis unit

BACKGROUND

Nosocomial transmission is the second most frequent cause of hepatitis C virus (HCV) infection. A prospective observational study was conducted to assess the roles of environmental contamination and noncompliance with standard precautions in HCV cross-transmission in a hemodialysis unit.

METHODS

Patients undergoing chronic hemodialysis in a French university hospital unit were systematically screened, revealing 2 sporadic cases of HCV transmission. An investigation was launched to determine whether the patients were infected in the hemodialysis unit and the possible roles of environmental contamination and noncompliance with standard precautions. We examined possible relationships among new cases of HCV infection, environmental contamination by blood and HCV RNA, and compliance with guidelines on hand hygiene and glove use.

RESULTS

Two patients experienced seroconversion to HCV during the study period. Phylogenetic analyses showed that 1 of these patients was infected with the same strain as that affecting a chronically infected patient also treated in the unit. Of 740 environmental surface samples, 82 (11%) contained hemoglobin; 6 (7%) of those contained HCV RNA. The rate of compliance with hand hygiene was 37% (95% confidence interval, 35%-39%), and gloves were immediately removed after patient care in 33% (95% confidence interval, 29%-37%) of cases. A low ratio of nurses to patients and poor hand hygiene were independent predictors of the presence of hemoglobin on environmental surfaces.

CONCLUSION

Blood-contaminated surfaces may be a source of HCV cross-transmission in a hemodialysis unit. Strict compliance with hand hygiene and glove use and strict organization of care procedures are needed to reduce the risk of HCV cross-transmission among patients undergoing hemodialysis.

Hepatitis B virus infection and the dialysis patient

Prevention of nosocomial transmission of hepatitis B virus (HBV) has been a signal achievement in the management of chronic kidney disease. The rate of serum hepatitis B surface antigen (HBsAg) seropositivity in patients on maintenance hemodialysis in the developed world is currently low (0-10%) but outbreaks of acute HBV infection continue to occur in this setting. The prevalence of HBV infection within dialysis units in developing countries appears higher (2-20%) based on relatively few reports. Although data are limited, HBV infection in dialysis population diminishes survival; HBV viral load in HBsAg-positive dialysis patients is reportedly low and stable over time. Updated recommendations for the management of HBsAg chronic carriers on maintenance dialysis have been issued. No rigorously controlled treatment trials for treatment of hepatitis B with either interferon or lamivudine therapy in dialysis patients are currently available.

[Chronic viral hepatitis and kidney failure]

Chronic viral hepatitis remains a major problem among patients with chronic renal failure. Hepatitis B and C viruses are frequent among dialysis patients and after renal transplantation and may significantly diminish the survival of both the patient and the graft. Hepatitis B and C viral infection in these patients is often characterized by normal transaminase levels despite viremia and progressive liver lesions. Liver biopsy remains essential for assessing the extent of liver disease. Cirrhosis is a contraindication to transplantation of only a kidney, because of elevated morbidity and mortality. A combined as liver-kidney transplantation may be considered. The best treatment of hepatitis infections is preventive: vaccination against the hepatitis B virus and attentive hygiene, especially to prevent nosocomial transmission. Among patients not awaiting transplant, antiviral treatment should be reserved for patients with active or even fibrotic liver disease. For hemodialysis patients awaiting kidney transplant: Alpha interferon is ineffective and poorly tolerated by dialysis patients. Lamivudine is effective and well tolerated, but its long-term efficacy and its optimal effective dose in dialysis patients remain unknown.

Hepatitis B virus genotypes circulating in Brazil: molecular characterization of genotype F isolates

Background

Hepatitis B virus (HBV) isolates have been classified in eight genotypes, A to H, which exhibit distinct geographical distributions. Genotypes A, D and F are predominant in Brazil, a country formed by a miscegenated population, where the proportion of individuals from Caucasian, Amerindian and African origins varies by region. Genotype F, which is the most divergent, is considered indigenous to the Americas. A systematic molecular characterization of HBV isolates from different parts of the world would be invaluable in establishing HBV evolutionary origins and dispersion patterns. A large-scale study is needed to map the region-by-region distribution of the HBV genotypes in Brazil.

Results

Genotyping by PCR-RFLP of 303 HBV isolates from HBsAg-positive blood donors showed that at least two of the three genotypes, A, D, and F, co-circulate in each of the five geographic regions of Brazil. No other genotypes were identified. Overall, genotype A was most prevalent (48.5%), and most of these isolates were classified as subgenotype A1 (138/153; 90.2%). Genotype D was the most common genotype in the South (84.2%) and Central (47.6%) regions. The prevalence of genotype F was low (13%) countrywide. Nucleotide sequencing of the S gene and a phylogenetic analysis of 32 HBV genotype F isolates showed that a great majority (28/32; 87.5%) belonged to subgenotype F2, cluster II. The deduced serotype of 31 of 32 F isolates was adw4. The remaining isolate showed a leucine-to-isoleucine substitution at position 127.

Conclusion

The presence of genotypes A, D and F, and the absence of other genotypes in a large cohort of HBV infected individuals may reflect the ethnic origins of the Brazilian population. The high prevalence of isolates from subgenotype A1 (of African origin) indicates that the African influx during the colonial slavery period had a major impact on the circulation of HBV genotype A currently found in Brazil. Although most genotype F isolates belonged to cluster II, the presence of some isolates belonging to clusters I (subgroup Ib) and IV suggests the existence of two or more founder viral populations of genotype F in Brazil.

Hepatitis B virus infection profile in hemodialysis patients in Central Brazil: prevalence, risk factors, and genotypes

Hemodialysis patients are at high risk for hepatitis B virus (HBV) infection. A survey was conducted in the hemodialysis population of the state of Goiás, Central Brazil, aiming to assess the prevalence of HBV infection, to analyse associated risk factors, and also to investigate HBV genotypes distribution. A total of 1095 patients were interviewed in 15 dialysis units. Serum samples were screened for HBV serological markers by enzyme-linked immunosorbent assay. Hepatitis B surface antigen (HBsAg) positive samples were tested for HBV DNA by polymerase chain reaction and genotyped by restriction fragment length polymorphism. Global HBV infection prevalence was 29.8% (95% CI: 27.1-32.5). Multivariate analysis of risk factors showed that male gender, length of time on hemodialysis, and blood transfusion before 1993 were associated with HBV positivity. HBV DNA was detected in 65.4% (17/26) of the HBsAg-positive samples. Thirteen of 17 HBV DNA positive samples were genotyped. Genotype D (61.5%) was predominant, followed by A (30.8%), while genotype F was detected in only one (7.7%) sample.

Chronic hepatitis B: current epidemiology in the Americas and implications for management

Hepatitis B virus (HBV) remains a serious health threat in many parts of the world. Although its prevalence is lower in the Americas than in Asia, Africa and the Middle East, it is responsible for significant morbidity and mortality in North, Central and South America. There is a nonuniform pattern of distribution throughout this region, with HBV prevalence related to geographical, social and cultural factors that predispose certain individuals to infection. This report details the incidence, modes of viral transmission of hepatitis B in the Americas and clinical course of disease in different regions of the Americas. Additionally, the implications for management focusing on issues predominant in high-risk populations are presented.

Prevalence of hepatitis C virus (HCV) infection and HCV genotypes of hemodialysis patients in Salvador, Northeastern Brazil

Hepatitis C virus (HCV) infection has been identified as the major cause of chronic liver disease among patients on chronic hemodialysis (HD), despite the important reduction in risks obtained by testing candidate blood donors for anti-HCV antibodies and the use of recombinant erythropoietin to treat anemia. A cross-sectional study was performed to estimate the prevalence of HCV infection and genotypes among HD patients in Salvador, Northeastern Brazil. Anti-HCV seroprevalence was determined by ELISA in 1243 HD patients from all ten different dialysis centers of the city. HCV infection was confirmed by RT-PCR and genotyping was performed by restriction fragment length polymorphism. Anti-HCV seroprevalence among HD patients was 10.5% (95% CI: 8.8-12.3) (Murex anti-HCV, Abbott Murex, Chicago, IL, USA). Blood samples for qualitative HCV detection and genotyping were collected from 125/130 seropositive HD patients (96.2%). HCV-RNA was detected in 92/125 (73.6%) of the anti-HCV-positive patients. HCV genotype 1 (77.9%) was the most prevalent, followed by genotype 3 (10.5%) and genotype 2 (4.6%). Mixed infections of genotypes 1 and 3 were found in 7.0% of the total number of patients. The present results indicate a significant decrease in anti-HCV prevalence from 23.8% detected in a study carried out in 1994 to 10.5% in the present study. The HCV genotype distribution was closely similar to that observed in other hemodialysis populations in Brazil, in local candidate blood donors and in other groups at risk of transfusion-transmitted infection.

Alternative methods for validation of cell culture infection with duck hepatitis B virus

Hepatitis B virus (HBV) is an important virus used in disinfection procedures for blood spillage. However, validation of HBV inactivation is difficult, since there are no feasible infectivity assays. In some countries, the duck HBV (DHBV) is recognized as a suitable model for testing antiviral activity of chemical biocides against HBV. Currently, DHBV-infected ducks are required for preparation of the test virus as well as eggs from DHBV-free flocks for testing DHBV infectivity. To improve the practicality of the system, we suggested to use commercially available embryonated duck eggs for preparation of DHBV-susceptible hepatocyte cultures and to exclude infected hepatocytes by pre-screening with qualitative detection of DHBV DNA using polymerase chain reaction (PCR). A standardized DHBV test virus was prepared from the DHBV DNA-transfected hepatoma cell line D2, which contained 10(11)DHBV DNA molecules per mL detected by light cycler real-time PCR. Infection of cell cultures was most efficient 4 days after plating. The best identification of infected cultures was possible 6 days after infection with immunofluorescence using an antiserum against DHBV surface antigen.

Hepatitis B virus infection in dialysis patients

Hepatitis B virus (HBV) infection remains a major issue among dialysis patients. It is associated with a high risk of hepatic complication. The liver disease runs a unique clinical course in dialysis patients, as it can progress with modest hepatic inflammation and prominent fibrosis. The conventional cut-off level of serum alanine aminotransferase (ALT) for commencing antiviral therapy may prove too high and inappropriate for dialysis patients, and liver biopsy appears to be the only definitive means to establish the activity of liver disease in dialysis patients. Liver biopsy should be considered in patients with a serum ALT level that is persistently greater than 30 IU/L, or 0.75-fold the upper limit of the normal level, and/or other clinical and laboratory findings that suggest active liver disease. For antiviral treatment, preliminary reports have shown that lamivudine is effective and well tolerated in dialysis patients. However, the long-term efficacy of lamivudine and its optimal effective dose in dialysis patients remain unknown. The prevention of nosocomial transmission among dialysis patients is also important. Universal precaution measures should be strictly observed and the segregation of hepatitis B surface antigen-positive hemodialysis patients should be considered. For HBV non-immune patients, the importance of HBV vaccination should not be overemphasized. Until a new generation of highly immunogenic vaccines that are proven to be safe and effective in patients with end-stage renal disease becomes available, early vaccination before the development of end-stage renal failure remains the best way to secure immunological protection against HBV infection in dialysis patients.