Epidemic history and evolutionary dynamics of hepatitis B virus infection in two remote communities in rural Nigeria

Intra-host diversity and evolution of hepatitis C virus endemic to Côte d'Ivoire

Hepatitis C virus (HCV) infection presents an important, but underappreciated public health problem in Africa. In Côte d'Ivoire, very little is known about the molecular dynamics of HCV infection. Plasma samples (n = 608) from pregnant women collected in 1995 from Côte d'Ivoire were analyzed in this study. Only 18 specimens (∼3%) were found to be HCV PCR-positive. Phylogenetic analysis of the HCV NS5b sequences showed that the HCV variants belong to genotype 1 (HCV1) (n = 12, 67%) and genotype 2 (HCV2) (n = 6, 33%), with a maximum genetic diversity among HCV variants in each genotype being 20.7% and 24.0%, respectively. Although all HCV2 variants were genetically distant from each other, six HCV1 variants formed two tight sub-clusters belonging to HCV1a and HCV1b. Analysis of molecular variance (AMOVA) showed that the genetic structure of HCV isolates from West Africa with Côte d'Ivoire included were significantly different from Central African strains (P = 0.0001). Examination of intra-host viral populations using next-generation sequencing of the HCV HVR1 showed a significant variation in intra-host genetic diversity among infected individuals, with some strains composed of sub-populations as distant from each other as viral populations from different hosts. Collectively, the results indicate a complex HCV evolution in Côte d'Ivoire, similar to the rest of West Africa, and suggest a unique HCV epidemic history in the country.

Molecular divergence and species delimitation of the cultivated oyster mushrooms: integration of IGS1 and ITS

Identification of edible mushrooms particularly Pleurotus genus has been restricted due to various obstacles. The present study attempted to use the combination of two variable regions of IGS1 and ITS for classifying the economically cultivated Pleurotus species. Integration of the two regions proved a high ability that not only could clearly distinguish the species but also served sufficient intraspecies variation. Phylogenetic tree (IGS1+ITS) showed seven distinct clades, each clade belonging to a separate species group. Moreover, the species differentiation was tested by AMOVA and the results were reconfirmed by presenting appropriate amounts of divergence (91.82% among and 8.18% within the species). In spite of achieving a proper classification of species by combination of IGS1 and ITS sequences, the phylogenetic tree showed the misclassification of the species of P. nebrodensis and P. eryngii var. ferulae with other strains of P. eryngii. However, the constructed median joining (MJ) network could not only differentiate between these species but also offer a profound perception of the species' evolutionary process. Eventually, due to the sufficient variation among and within species, distinct sequences, simple amplification, and location between ideal conserved ribosomal genes, the integration of IGS1 and ITS sequences is recommended as a desirable DNA barcode.

Bayesian inference of the evolution of HBV/E

Despite its wide spread and high prevalence in sub-Saharan Africa, hepatitis B virus genotype E (HBV/E) has a surprisingly low genetic diversity, indicating an only recent emergence of this genotype in the general African population. Here, we performed extensive phylogeographic analyses, including Bayesian MCMC modeling. Our results indicate a mutation rate of 1.9×10⁻⁴ substitutions per site and year (s/s/y) and confirm a recent emergence of HBV/E, most likely within the last 130 years, and only after the transatlantic slave-trade had come to an end. Our analyses suggest that HBV/E originated from the area of Nigeria, before rapidly spreading throughout sub-Saharan Africa. Interestingly, viral strains found in Haiti seem to be the result of multiple introductions only in the second half of the 20th century, corroborating an absence of a significant number of HBV/E strains in West Africa several centuries ago. Our results confirm that the hyperendemicity of HBV(E) in today's Africa is a recent phenomenon and likely the result of dramatic changes in the routes of viral transmission in a relatively recent past.

Genetic relatedness among hepatitis A virus strains associated with food-borne outbreaks

The genetic characterization of hepatitis A virus (HAV) strains is commonly accomplished by sequencing subgenomic regions, such as the VP1/P2B junction. HAV genome is not extensively variable, thus presenting opportunity for sharing sequences of subgenomic regions among genetically unrelated isolates. The degree of misrepresentation of phylogenetic relationships by subgenomic regions is especially important for tracking transmissions. Here, we analyzed whole-genome (WG) sequences of 101 HAV strains identified from 4 major multi-state, food-borne outbreaks of hepatitis A in the Unites States and from 14 non-outbreak-related HAV strains that shared identical VP1/P2B sequences with the outbreak strains. Although HAV strains with an identical VP1/P2B sequence were specific to each outbreak, WG were different, with genetic diversity reaching 0.31% (mean 0.09%). Evaluation of different subgenomic regions did not identify any other section of the HAV genome that could accurately represent phylogenetic relationships observed using WG sequences. The identification of 2–3 dominant HAV strains in 3 out of 4 outbreaks indicates contamination of the implicated food items with a heterogeneous HAV population. However, analysis of intra-host HAV variants from eight patients involved in one outbreak showed that only a single sequence variant established infection in each patient. Four non-outbreak strains were found closely related to strains from 2 outbreaks, whereas ten were genetically different from the outbreak strains. Thus, accurate tracking of HAV strains can be accomplished using HAV WG sequences, while short subgenomic regions are useful for identification of transmissions only among cases with known epidemiological association.

Disparate distribution of hepatitis B virus genotypes in four sub-Saharan African countries

BACKGROUND

Hepatitis B virus (HBV) places a substantial health burden on Africa. Here, we investigated genetic diversity of HBV variants circulating in 4 countries of sub-Saharan Africa using archived samples. In total, 1492 plasma samples were tested from HIV-infected individuals and pregnant women, among which 143 (9.6%) were PCR-positive for HBV DNA (Côte d'Ivoire, 70/608 [11.5%]; Ghana, 13/444 [2.9%]; Cameroon, 33/303 [10.9%]; and Uganda, 27/137 [19.7%]).

STUDY DESIGN/RESULTS

Phylogenetic analysis of the S-gene sequences identified HBV genotypes E (HBV/E, n=96) and A (HBV/A, n=47) distributed as follows: 87% of HBV/E and 13% of HBV/A in Côte d'Ivoire; 100% of HBV/E in Ghana; 67% of HBV/E and 33% of HBV/A in Cameroon; and 100% of HBV/A in Uganda. The average and maximal nucleotide distances among HBV/E sequences were 1.9% and 6.4%, respectively, suggesting a greater genetic diversity for this genotype than previously reported (p<0.001). HBV/A strains were classified into subgenotypes HBV/A1, HBV/A2 and HBV/A3. In Uganda, 93% of HBV/A strains belonged to HBV/A1 whereas HBV/A3 was the only subgenotype of HBV/A found in Cameroon. In Côte d'Ivoire, HBV/A strains were classified as HBV/A1 (11.1%), HBV/A2 (33.3%) and HBV/A3 (55.6%). Phylogeographic analysis of the sequences available from Africa supported earlier suggestions on the origin of HBV/A1, HBV/A2 and HBV/A3 in East, South and West/Central Africa, respectively. Using predicted amino acid sequences, hepatitis B surface antigen (HBsAg) was classified into serotype ayw4 in 93% of HBV/E strains and adw2 in 68% of HBV/A strains. Also, 7.7% of the sequences carried substitutions in HBsAg associated with immune escape.

CONCLUSIONS

The observations of pan-African and global dissemination of HBV/A1 and HBV/A2, and the circulation of HBV/E and HBV/A3 almost exclusively in West and Central Africa suggest a more recent increase in prevalence in Africa of HBV/E and HBV/A3 compared to HBV/A1 and HBV/A2. The broad genetic heterogeneity of HBsAg detected here may impact the efficacy of prevention and control efforts in sub-Saharan Africa.

Molecular epidemiology and genetic diversity of hepatitis B virus in Mar del Plata city, Argentina

The aim of this work was to describe the current molecular epidemiology and genetic diversity of HBV in Mar del Plata, an important Argentinean touristic city. The phylogenetic analysis of 29 HBV DNA positive serum samples showed that F1b was the predominant subgenotype (sgt, 62.1%), followed by sgt A2 (13.8%) and sgt F4, gt D and gt G (6.9% each). Among anti-HBc IgM positive samples, 75.0% were sgt F1b, followed by sgt F4 (12.5%), sgt A2 (6.25%) and sgt D (6.25%). Three recombinant full length genomes were found: two G/F1b (some of the first gt G detected in Argentina) and one F4/D2. The circulation of clinical important mutations in the city was described. Mutations at the HBsAg were detected in 34.5% of the analyzed samples, associated with laboratory diagnosis and antiviral treatment failures, immune escape and hepatocellular carcinoma. Most of the samples presented wild type BCP/PC sequences. Coalescence analysis for the most prevalent sgt F1b estimated that the diversification mainly occured during mid '90s and the tMRCA was estimated in 1987. Finally, the high presence of the autochthonous sgt F1b, associated with the anti-HBc IgM positive infection and its present-day diversification process, shows the strong impact of internal human migratory movements into the current population of Mar del Plata.

Acute hepatitis B outbreaks in 2 skilled nursing facilities and possible sources of transmission: North Carolina, 2009-2010

OBJECTIVE

Acute hepatitis B virus (HBV) infections have been reported in long-term care facilities (LTCFs), primarily associated with infection control breaks during assisted blood glucose monitoring. We investigated HBV outbreaks that occurred in separate skilled nursing facilities (SNFs) to determine factors associated with transmission.

DESIGN

Outbreak investigation with case-control studies.

SETTING

Two SNFs (facilities A and B) in Durham, North Carolina, during 2009-2010.

PATIENTS

Residents with acute HBV infection and controls randomly selected from HBV-susceptible residents during the outbreak period.

METHODS

After initial cases were identified, screening was offered to all residents, with repeat testing 3 months later for HBV-susceptible residents. Molecular testing was performed to assess viral relatedness. Infection control practices were observed. Case-control studies were conducted to evaluate associations between exposures and acute HBV infection in each facility.

RESULTS

Six acute HBV cases were identified in each SNF. Viral phylogenetic analysis revealed a high degree of HBV relatedness within, but not between, facilities. No evaluated exposures were significantly associated with acute HBV infection in facility A; those associated with infection in facility B (all odds ratios >20) included injections, hospital or emergency room visits, and daily blood glucose monitoring. Observations revealed absence of trained infection control staff at facility A and suboptimal hand hygiene practices during blood glucose monitoring and insulin injections at facility B.

CONCLUSIONS

These outbreaks underscore the vulnerability of LTCF residents to acute HBV infection, the importance of surveillance and prompt investigation of incident cases, and the need for improved infection control education to prevent transmission.

Molecular epidemiology of hepatitis B in the Indigenous people of northern Australia

BACKGROUND AND AIM

The hepatitis B surface antigen was first described in the blood of an Indigenous Australian man, yet little is known about its molecular epidemiology in this population, in which it is endemic. The study aimed to determine the clinical and molecular epidemiology of hepatitis B virus (HBV) in Indigenous people from northern Australia.

METHODS

Following ethics approval and informed consent, blood specimens and clinical details from Indigenous adults known to be infected with HBV and who were born and raised in Indigenous communities in northern Australia were obtained. HBV genotypes were determined in isolates with sufficient HBV DNA by polymerase chain reaction by sequencing of the polymerase/surface gene.

RESULTS

Between June 2010 and June 2012, 65 patients were recruited from six different regions of northern Australia. Thirty-two patients (49%) were hepatitis B e-antigen-positive, and 48% were hepatitis B e-antibody-positive. No patients were found to be coinfected with hepatitis C virus or human immunodeficiency virus. Of the 49 samples with sufficient viral load for genotyping, 100% were infected with genotype C4, previously only reported from two Indigenous Australians. All isolates had wild-type polymerase gene sequences despite 14 currently or previously receiving antiviral treatment. The canonical sG145R vaccine-escape variant was detected in the surface antigen of virus from two patients.

CONCLUSIONS

The exclusive HBV genotype in this ancient population is genotype C4. Whole genome sequencing and clinical follow-up of this cohort are in progress, with the aim of exploring the clinical significance of these findings.

Genetic diversity of hepatitis B virus genotypes B6, D and F among circumpolar indigenous individuals

Hepatitis B virus (HBV) infection is highly prevalent in circumpolar indigenous peoples. However, the clinical outcome is extremely variable, such that while hepatocellular carcinoma (HCC) is uncommon in Canadian Inuit, the incidence of HCC is slightly higher in Greenlanders than in Danes, and it is especially high in Alaskan Native people infected with HBV genotypes F (HBV/F) and C (HBV/C). These differences may be associated with the genomic variability of the predominant HBV genotype in each group. The purpose of this study was to determine the rate, nature and regional susceptibility of HBV genomic mutations among circumpolar indigenous individuals. Paired serum samples, separated by 5-6 years, were analysed from Canadian and Greenlandic Inuit infected with HBV genotype B6 (HBV/B6) and HBV/D, respectively, and from Alaskan Native people infected with HBV/F, each having subsequently developed HCC. Phylogenetic and mutational analyses were performed on full-genome sequences, and the dynamic evolution within the quasispecies population of each patient group was determined by clonal analysis of the non-overlapping core coding region. Mutations associated with severe outcomes predominated in HBV/F, mostly within the precore/core and PreS1 region. HBV/B6 genomes exhibited higher diversity compared to HBV/D and HBV/F, particularly within the core coding region. Thus, differing mutational profiles and genetic variability were observed among different HBV genotypes predominating in circumpolar indigenous patients. The unusual observation of persistently high genetic variability with HBV/B6 despite clinical inactivity could be due to the evolution of a host-pathogen balance, but other possible factors also need to be explored.

Hepatitis B virus transmissions associated with a portable dental clinic, West Virginia, 2009

BACKGROUND

Although hepatitis B virus (HBV) transmission in dental settings is rare, in 2009 a cluster of acute HBV infections was reported among attendees of a two-day portable dental clinic in West Virginia.

METHODS

The authors conducted a retrospective investigation by using treatment records and volunteer logs, interviews of patients and volunteers with acute HBV infection as well as of other clinic volunteers, and molecular sequencing of the virus from those acutely infected.

RESULTS

The clinic was held under the auspices of a charitable organization in a gymnasium staffed by 750 volunteers, including dental care providers who treated 1,137 adults. Five acute HBV infections-involving three patients and two volunteers-were identified by the local and state health departments. Of four viral isolates available for testing, all were genotype D. Three case patients underwent extractions; one received restorations and one a dental prophylaxis. None shared a treatment provider with any of the others. One case volunteer worked in maintenance; the other directed patients from triage to the treatment waiting area. Case patients reported no behavioral risk factors for HBV infection. The investigation revealed numerous infection control breaches.

CONCLUSIONS

Transmission of HBV to three patients and two volunteers is likely to have occurred at a portable dental clinic. Specific breaches in infection control could not be linked to these HBV transmissions.

PRACTICAL IMPLICATIONS

All dental settings should adhere to recommended infection control practices, including oversight; training in prevention of bloodborne pathogens transmission; receipt of HBV vaccination for staff who may come into contact with blood or body fluids; use of appropriate personal protective equipment, sterilization and disinfection procedures; and use of measures, such as high-volume suction, to minimize the spread of blood.

Outbreak of hepatitis B virus infections associated with assisted monitoring of blood glucose in an assisted living facility-Virginia, 2010

Introduction

In January 2010, the Virginia Department of Health received reports of 2 hepatitis B virus (HBV) infections (1 acute, 1 chronic) among residents of a single assisted living facility (ALF). Both infected residents had diabetes and received assisted monitoring of blood glucose (AMBG) at the facility. An investigation was initiated in response.

Objective

To determine the extent and mechanism of HBV transmission among ALF residents.

Design

Retrospective cohort study.

Setting

An ALF that primarily housed residents with neuropsychiatric disorders in 2 adjacent buildings in Virginia.

Participants

Residents of the facility as of March 2010.

Measurements

HBV serologic testing, relevant medical history, and HBV genome sequences. Risk ratios (RR) and 95% confidence intervals (CIs) were used to identify risk factors for HBV infection.

Results

HBV serologic status was determined for 126 (91%) of 139 residents. Among 88 susceptible residents, 14 became acutely infected (attack rate, 16%), and 74 remained uninfected. Acute HBV infection developed among 12 (92%) of 13 residents who received AMBG, compared with 2 (3%) of 75 residents who did not (RR  = 35; 95% CI, 8.7, 137). Identified infection control breaches during AMBG included shared use of fingerstick devices for multiple residents. HBV genome sequencing demonstrated 2 building-specific phylogenetic infection clusters, each having 99.8–100% sequence identity.

Limitations

Transfer of residents out of the facility prior to our investigation might have contributed to an underestimate of cases. Resident interviews provided insufficient information to fully assess behavioral risk factors for HBV infection.

Conclusions

Failure to adhere to safe practices during AMBG resulted in a large HBV outbreak. Protection of a growing and vulnerable ALF population requires improved training of staff and routine facility licensing inspections that scrutinize infection control practices.

Prevalence of hepatitis B e antigen in chronic HBV carriers in North-central Nigeria

Hepatitis B virus (HBV) is an important clinical problem due to its worldwide distribution and potential of adverse sequelae, including hepatocellular carcinoma (HCC). We studied the prevalence of hepatitis B virus e antigen (HBeAg) among individuals determined to be HBV surface antigen-positive (HBsAg+) and analyzed the gender/age category associated with more active HBV infection. A total of 572 HBsAg+ individuals, as determined by a double antibody sandwich ELISA method, participated in the study. They were tested for HbeAg, using a lateral flow chromatographic immunoassay. One hundred and ten individuals were found to be HBeAg-positive giving an overall prevalence of 19.2%. Of these 110 individuals, 20 (18.2%) were females, and 90 (81.8%) were males. Thus, the prevalence of HBeAg appears to be higher in males than in females (p < 0.05). Our data also revealed that the prevalence of HBeAg was higher in patients between the age-group of 0-10 years and 11-20 years and appeared to decrease with increase in age. Taken together, our data show that approximately 1/5 of HBV-infected individuals are HBeAg+, suggesting that the virus is actively replicating and infecting liver-cells thereby ensuring an HBV-transmission pool within the Nigerian population. We suggest strengthening of the childhood HBV vaccination programmes, massive intervention activities, and treatment programmes, especially among young people to reverse the possible devastating effect of HBV infection. The success of these efforts will depend on our resolution to make the elimination of HBV infection a top priority on the public-health agenda as we start the second decade of this new century.

Epidemiological pattern of hepatitis B and hepatitis C as etiological agents for hepatocellular carcinoma in iran and worldwide

CONTEXT

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections constitute a major global health problem. About 60,000 and 350,000 deaths occur as the results of HBV and HCV infections, respectively. Chronic hepatitis B and C infections are leading causes of cirrhosis and hepatocellular carcinoma (HCC) which are considered as the third cancer-associated cause of deaths worldwide. Iran suffers from the same problem but to a lesser extent as it is considered as a low endemic area for HBV and HCV infections and also as a low incidence area of HCC. This study was conducted to assess and provide a clear picture about epidemiology of HBV and HCV infections in Iran and worldwide, with the consequence on HCC distribution all over the world including Iran, and to analyze current literature regarding the modes of transmission and risk factors of HBV and HCV infections.

EVIDENCE ACQUISITION

In this review, we performed electronic and manual searches on available databases such as MEDLINE, PubMed, Ovid, Embase, and the Iranian databases such as IranMedex. We also performed a Google search to find related articles.

RESULTS

HBV and HCV infections are the most common risk factors of hepatocellular carcinoma. The epidemiology of HCC usually follows that of HBV and HCV infections. With the introduction of HBV national vaccine in Iran and worldwide, there is a noticeable effect on reduction in HBV prevalence in most countries, and we expect that HCV will replace HBV as a major risk factor of HCC in Iran and worldwide. Alcohol plays a minor role as a risk factor for cirrhosis and HCC in Iran, Asia, and Africa, despite its noticeable role in Europe and the USA.

CONCLUSIONS

Vaccination against HBV remains the most effective approach against HBV infection with consequence decrease in HBV-related HCC. There is a need to improve the awareness about epidemiology of HBV and HCV infections, modes of transmission, and their complications, specifically HCC among population.

Transmission of hepatitis B virus from an orthopedic surgeon with a high viral load

BACKGROUND

During the evaluation of a needle-stick injury, an orthopedic surgeon was found to be unknowingly infected with hepatitis B virus (HBV) (viral load >17.9 million IU/mL). He had previously completed two 3-dose series of hepatitis B vaccine without achieving a protective level of surface antibody. We investigated whether any surgical patients had acquired HBV infection while under his care.

METHODS

A retrospective cohort study of all patients who underwent surgery by the surgeon was conducted. Patients were notified of their potential exposure and need for testing, and samples with positive HBV loads underwent DNA sequencing. Characteristics of the surgical procedures for the cohort were evaluated.

RESULTS

A total of 232 (70.7%) of potentially exposed patients consented to testing; 2 were found to have acute infection and 6 had possible transmission (evidence of past exposure without risk factors). Genome sequence analysis of HBV DNA from the infected surgeon and patients with acute infection revealed genetically related virus (>99.9% nucleotide identity). Only age was found to be statistically different between those with confirmed or possible HBV transmission and those who remained susceptible to HBV.

CONCLUSIONS

We documented HBV transmission during orthopedic surgery to 2 patients from a surgeon with HBV. This investigation highlights the importance of evaluating individuals who do not respond to 2 series of HBV vaccination, the increased risk of HBV transmission from providers with high viral loads, and the need to evaluate the clinical practice of providers with HBV and implement appropriate procedure-based practice restrictions.

Transmission of hepatitis B virus associated with assisted monitoring of blood glucose at an assisted living facility in New York State

BACKGROUND

Hepatitis B virus (HBV) transmission has been reported after patient-to-patient blood exposure during assisted monitoring of blood glucose (AMBG). Three assisted-living facility (ALF) residents who underwent AMBG developed acute HBV infection (HBVI) within 10 days. We investigated HBV transmission and implemented preventive measures.

METHODS

A retrospective cohort study was conducted. Infection control practices were assessed. HBVI screening was conducted for all staff and epidemiologically linked residents. Viral DNA sequences were compared for a subset of isolates.

RESULTS

Lancing devices and glucometers were shared among residents without proper sanitization. Serologic testing of all 34 residents with diabetes and 12 epidemiologically linked residents present during the exposure period detected 6 residents with diabetes with current HBVI and 4 residents with diabetes and 1 epidemiologically linked resident with previous HBVI. A cohort study of 32 individuals with diabetes identified AMBG as a significant risk factor for HBVI (relative risk, 6.7; 95% confidence interval, 1.7-26.3). Viral DNA sequences for 5 AMBG-exposed residents' isolates were identical, suggesting a common source.

CONCLUSIONS

AMBG was significantly associated with HBVI in ALF residents with diabetes. Despite clear preventive recommendations, bloodborne pathogen transmission continues to occur in the setting of AMBG. Strengthening direct care provider, infection preventionist, and health department partnerships with ALFs is crucial to ensure safe AMBG practices and prevent HBV transmission.

TP53 R249S mutation, genetic variations in HBX and risk of hepatocellular carcinoma in The Gambia

In regions with high prevalence of chronic hepatitis B virus (HBV) infection and dietary aflatoxin B(1) (AFB(1)) exposure, hepatocellular carcinomas (HCCs) often contain TP53 mutation at codon 249 (R249S). Furthermore, a C-terminal truncated HBx protein expressed from hepatocyte integrated HBV is associated with HCC development. This study evaluates the association between R249S and HBX status in relation to HCC in West African population. HBX (complete or 3'-truncated) and HBS genes were assessed by PCR in cell-free DNA (CFDNA) from plasma of subjects recruited in a hospital-based case-control study (325 controls, 78 cirrhotic patients and 198 HCC cases) conducted in The Gambia. These samples had been previously analyzed for R249S and HBV serological status. Complete HBX sequence was frequently detected in CFDNA of HCC-R249S positive (77%, 43/56) compared with HCC-R249S-negative cases (44%, 22/50). Conversely, the proportion of 3'-truncated HBX gene was significantly higher in HCC-R249S negative than positive cases (34%, 17/50, compared with 12%, 7/56) (χ(2) = 12.12; P = 0.002; distribution of R249S negative and positive according to HBX status). Occult HBV infection (detected by PCR) was present in 24% of HCC previously considered as negative by HBV serology. Moreover, HBV mutation analysis revealed that double mutation at nucleotides 1762(T)/1764(A) was associated with diagnosis of cirrhosis or HCC {cirrhosis: odds ratio (OR): 9.50 [95% confidence interval (CI) 1.50-60.11]; HCC: OR: 11.29 [95% CI 2.07-61.47]}. These findings suggest that in HCC from The Gambia, complete HBX sequences are often associated with the presence of TP53 R249S mutation.

Investigation of hepatitis B virus and human immunodeficiency virus transmission among severely mentally ill residents at a long term care facility

Background

A high prevalence of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) infections have been reported among persons with severe mental illness. In October, 2009, the Cook County Department of Public Health (CCDPH) initiated an investigation following notification of a cluster of HBV infections among mentally ill residents at a long term care facility (LTCF).

Methods

LTCF staff were interviewed and resident medical records were reviewed. Residents were offered testing for HBV, HCV, and HIV. Serum specimens from residents diagnosed with HBV or HIV infection were sent to the Centers for Disease Control and Prevention (CDC) for analysis.

Results

Eleven newly diagnosed HBV infections were identified among mentally ill residents at the LTCF. Of these 11 infections, 4 serum specimens were available for complete HBV genome sequencing; all 4 genomes were found to be closely related. Four newly diagnosed HIV infections were identified within this same population. Upon molecular analysis, 2 of 4 HIV sequences from these new infections were found to be nearly identical and formed a tight phylogenetic cluster.

Conclusions

HBV and HIV transmission was identified among mentally ill residents of this LTCF. Continued efforts are needed to prevent bloodborne pathogen transmission among mentally ill residents in LTCFs.

TP53 R249S mutation, genetic variations in HBX and risk of hepatocellular carcinoma in The Gambia

In regions with high prevalence of chronic hepatitis B virus (HBV) infection and dietary aflatoxin B(1) (AFB(1)) exposure, hepatocellular carcinomas (HCCs) often contain TP53 mutation at codon 249 (R249S). Furthermore, a C-terminal truncated HBx protein expressed from hepatocyte integrated HBV is associated with HCC development. This study evaluates the association between R249S and HBX status in relation to HCC in West African population. HBX (complete or 3'-truncated) and HBS genes were assessed by PCR in cell-free DNA (CFDNA) from plasma of subjects recruited in a hospital-based case-control study (325 controls, 78 cirrhotic patients and 198 HCC cases) conducted in The Gambia. These samples had been previously analyzed for R249S and HBV serological status. Complete HBX sequence was frequently detected in CFDNA of HCC-R249S positive (77%, 43/56) compared with HCC-R249S-negative cases (44%, 22/50). Conversely, the proportion of 3'-truncated HBX gene was significantly higher in HCC-R249S negative than positive cases (34%, 17/50, compared with 12%, 7/56) (χ(2) = 12.12; P = 0.002; distribution of R249S negative and positive according to HBX status). Occult HBV infection (detected by PCR) was present in 24% of HCC previously considered as negative by HBV serology. Moreover, HBV mutation analysis revealed that double mutation at nucleotides 1762(T)/1764(A) was associated with diagnosis of cirrhosis or HCC {cirrhosis: odds ratio (OR): 9.50 [95% confidence interval (CI) 1.50-60.11]; HCC: OR: 11.29 [95% CI 2.07-61.47]}. These findings suggest that in HCC from The Gambia, complete HBX sequences are often associated with the presence of TP53 R249S mutation.

Convergence and coevolution of hepatitis B virus drug resistance

Treatment with lamivudine of patients infected with hepatitis B virus (HBV) results in a high rate of drug resistance, which is primarily associated with the rtM204I/V substitution in the HBV reverse transcriptase domain. Here we show that the rtM204I/V substitution, although essential, is insufficient for establishing resistance against lamivudine. The analysis of 639 HBV whole-genome sequences obtained from 11 patients shows that rtM204I/V is independently acquired by more than one intra-host HBV variant, indicating the convergent nature of lamivudine resistance. The differential capacity of HBV variants to develop drug resistance suggests that fitness effects of drug-resistance mutations depend on the genetic structure of the HBV genome. An analysis of Bayesian networks that connect rtM204I/V to many sites of HBV proteins confirms that lamivudine resistance is a complex trait encoded by the entire HBV genome rather than by a single mutation. These findings have implications for public health and offer a more general framework for understanding drug resistance.

Epidemic history of hepatitis C virus infection in two remote communities in Nigeria, West Africa

We investigated the molecular epidemiology and population dynamics of HCV infection among indigenes of two semi-isolated communities in North-Central Nigeria. Despite remoteness and isolation, ~15% of the population had serological or molecular markers of hepatitis C virus (HCV) infection. Phylogenetic analysis of the NS5b sequences obtained from 60 HCV-infected residents showed that HCV variants belonged to genotype 1 (n=51; 85%) and genotype 2 (n=9; 15%). All sequences were unique and intermixed in the phylogenetic tree with HCV sequences from people infected from other West African countries. The high-throughput 454 pyrosequencing of the HCV hypervariable region 1 and an empirical threshold error correction algorithm were used to evaluate intra-host heterogeneity of HCV strains of genotype 1 (n=43) and genotype 2 (n=6) from residents of the communities. Analysis revealed a rare detectable intermixing of HCV intra-host variants among residents. Identification of genetically close HCV variants among all known groups of relatives suggests a common intra-familial HCV transmission in the communities. Applying Bayesian coalescent analysis to the NS5b sequences, the most recent common ancestors for genotype 1 and 2 variants were estimated to have existed 675 and 286 years ago, respectively. Bayesian skyline plots suggest that HCV lineages of both genotypes identified in the Nigerian communities experienced epidemic growth for 200-300 years until the mid-20th century. The data suggest a massive introduction of numerous HCV variants to the communities during the 20th century in the background of a dynamic evolutionary history of the hepatitis C epidemic in Nigeria over the past three centuries.

Identification of novel inter-genotypic recombinants of human hepatitis B viruses by large-scale phylogenetic analysis

Recombination plays an important role in the evolutionary history of Hepatitis B virus (HBV). We performed a phylogenetic analysis of 3403 full-length HBV genome sequences isolated from humans to define the genotype. The genome sequences were divided into 13 sub-datasets, each approximately 250 bp in length. Genotype designations obtained from the sub-datasets that differed from the genotype defined by the whole genome were assigned as putative recombinants. Our results showed that 3379 out of 3403 sequences belonged to the previously described and putative genotypes A to J respectively, with 315 sequences defined in this analysis. The remaining 24 viruses had sequence divergence of less than 8% with both genotypes B and C and were provisionally assigned genotype "BC". 1047 out of 3403 sequences were identified to be putative recombinants, of which 72 were identified to be novel recombinants. Notably, all viruses of the herein described genotype "BC" were identified to be B/C recombinants.

Chronic hepatitis B: management challenges in resource-poor countries

Sylvester Chuks Nwokediuko, Department of Medicine, University of Nigeria Teaching Hospital, Ituku OzallaChronic infection with hepatitis B virus (HBV) is a global public health problem because of its worldwide distribution and its potential to cause sequelae. HBV is most prevalent in China, South East Asia, sub-Saharan Africa, and the Amazon basin of South America where health care resources are most limited. Numerous challenges exist for effective management of chronic HBV infection, particularly in resource-limited regions. These challenges include lack of accurate prevalence data, absence of a surveillance program, and poor political will of governments in resource-poor countries to enforce effective measures to control the disease. There is a lack of understanding regarding HBV infec-tion by both the general public and health care providers. A better understanding of the pathogenesis and treatment of this condition is necessary. The acute shortage of trained medical manpower necessary for accurate diagnosis and treatment of chronic hepati-tis B (CHB) in resource-poor countries is a formidable challenge. The condition is com-plicated by the continuing efflux of medical graduates from low-income economies to richer countries. The most critical problem in the management of CHB is the high cost of laboratory tests and drugs. Drugs are also not readily available. Other challenges in the manage-ment of CHB include stigmatization of patients, co-infection with other viruses, lack of management guidelines, and absence of an effective patient referral system. To address these challenges, governments of resource-poor nations must be committed to budg-etary allocation for the implementation of health programs. It is necessary to provide awareness campaigns, health education, proper screening of blood and blood products for transfusion, active screening, intensification of existing childhood immunization, technical and financial assistance from wealthier nations, and implementation of the recommendations outlined in the Global Hepatitis Policy (2010).

Evaluation of intra-host variants of the entire hepatitis B virus genome

Genetic analysis of hepatitis B virus (HBV) frequently involves study of intra-host variants, identification of which is commonly achieved using short regions of the HBV genome. However, the use of short sequences significantly limits evaluation of genetic relatedness among HBV strains. Although analysis of HBV complete genomes using genetic cloning has been developed, its application is highly labor intensive and practiced only infrequently. We describe here a novel approach to whole genome (WG) HBV quasispecies analysis based on end-point, limiting-dilution real-time PCR (EPLD-PCR) for amplification of single HBV genome variants, and their subsequent sequencing. EPLD-PCR was used to analyze WG quasispecies from serum samples of patients (n = 38) infected with HBV genotypes A, B, C, D, E and G. Phylogenetic analysis of the EPLD-isolated HBV-WG quasispecies showed the presence of mixed genotypes, recombinant variants and sub-populations of the virus. A critical observation was that HBV-WG consensus sequences obtained by direct sequencing of PCR fragments without EPLD are genetically close, but not always identical to the major HBV variants in the intra-host population, thus indicating that consensus sequences should be judiciously used in genetic analysis. Sequence-based studies of HBV WG quasispecies should afford a more accurate assessment of HBV evolution in various clinical and epidemiological settings.

Genotypic distribution of hepatitis B virus (HBV) among acute cases of HBV infection, selected United States counties, 1999-2005

BACKGROUND

Knowledge of the genotypic distribution of hepatitis B virus (HBV) facilitates epidemiologic tracking and surveillance of HBV infection as well as prediction of its disease burden. In the United States, HBV genotyping studies have been conducted for chronic but not acute hepatitis B.

METHODS

Serum samples were collected from patients with acute hepatitis B cases reported from the 6 counties that participated in the Sentinel Counties Study of Acute Viral Hepatitis from 1999 through 2005. Polymerase chain reaction followed by nucleotide sequencing of a 435-base pair segment of the HBV S gene was performed, and the sequences were phylogenetically analyzed.

RESULTS

Of 614 patients identified with available serum samples, 75% were infected with genotype A HBV and 18% were infected with genotype D HBV. Thirty-two percent of genotype A sequences constituted a single subgenotype A2 cluster. The odds of infection with genotype A (vs with genotype D) were 5 times greater among black individuals than among Hispanic individuals (odds ratio [OR], 5; 95% confidence interval [CI], 2.3-10.7). The odds of infection with genotype A were 49, 8, and 4 times greater among patients from Jefferson County (Alabama), Pinellas County (Florida), and San Francisco (California), respectively, than among those living in Denver County (Colorado). Genotype A was less common among recent injection drug users than it was among non-injection drug users (OR, 0.2; 95% CI, 0.1-0.4).

CONCLUSIONS

HBV genotype distribution was significantly associated with ethnicity, place of residence, and risk behavior.