Confirmation of nosocomial transmission of hepatitis C virus by phylogenetic analysis of the NS5-B region

Transmission of hepatitis C virus infection in hemodialysis: Current concepts

A variety of epidemiological data provides evidence for the occurrence of nosocomial transmission of hepatitis C virus (HCV) infection to hemodialysis (HD) patients. The most important factor implicated in HCV transmission between patients treated in the same dialysis unit is cross-contamination from supplies and surfaces as a result of failure of staff to follow infection control procedures. Parts of the HCV genome are highly variable and lend themselves to fingerprinting of each isolate using nucleic acid testing (NAT) and sequencing. This approach has permitted investigation of possible transmission routes within HD units. A systematic review of molecular virology papers revealed transmission of HCV via internal fluid pathways of the dialysis machines in a minority of reports only. Dialyzer reuse was not identified as a risk factor for HCV acquisition in multicenter databases. No randomized controlled trials exist on the impact of isolation on the risk of transmission of HCV to hemodialysis patients. A Belgian prospective multicenter study showed a reduction from 1.4% to 0% in the annual incidence of seroconversion for HCV without any isolation measures, by implementation of strict infection control procedures designed to prevent transmission of blood-borne pathogens, including HCV. However, an isolation policy for HCV-infected dialysis patients should be considered in dialysis units where nosocomial transmission of HCV persists despite reinforcement and audit of hygienic precautions for hemodialysis. Routine audit precautions (general and for dialysis machines) are recommended on a regular basis within HD units.

Subtyping of hepatitis C virus with high resolution mass spectrometry

A proteotyping approach using high resolution mass spectrometry has been applied, for the first time, to subtype the hepatitis C virus based upon detection of one or more signature peptides derived from the E1 and E2 envelope glycoproteins. These signature peptides represent conserved peptide segments within these proteins for particular subtypes of the virus that are found to be unique in mass when compared with the theoretical masses for all peptide segments of translated HCV proteins within a specifically constructed database. The successful application of the approach to three different subtypes of the virus (i.e., 1a, 1b and 2b) is demonstrated for protein and whole virus proteolytic digests. The approach has the potential to replace existing PCR-based subtyping by offering a more direct and cost comparable strategy that is not challenged by mixed infection scenarios.

A Large Nosocomial Outbreak of Hepatitis C Virus Infections at a Hemodialysis Center

Objective:

To identify modes of HCV transmission during an outbreak of HCV infection in a hemodialysis unit.

Design:

An epidemiologic study, virologie analysis, assessment of infection control practices and procedures, and technical examination of products and dialysis machines.

Setting:

A private hemodialysis unit treating approximately 70 patients.

Patients:

Detection of HCV RNA by PCR was performed among patients receiving dialysis in 2001. Case-patients were patients who had a first positive result for HCV RNA between January 2001 and January 2002 and either acute hepatitis, a seroconversion for HCV antibodies, or a previous negative result. Three control-patients were randomly selected per case-patient.

Results:

Of the 61 patients treated in the unit in 2001 and not infected with HCV, 22 (36.1%) became case-patients with onset from May 2001 to January 2002 for an incidence density rate of 70 per 100 patient-years. Phylogenic analysis identified four distinct HCV groups and an index case-patient for each with a similar virus among patients already known to be infected. No multidose medication vials or material was shared between patients. Connection to a dialysis machine by a nurse who had connected an HCV-infected patient “just before” or “one patient before” increased the risk of HCV infection, whereas using the same dialysis machine after a patient infected with HCV did not. Understating, lack of training, and breaches in infection control were documented. Direct observation of practices revealed frequent flooding of blood into the double filter on the arterial pressure tubing set.

Conclusions:

During this outbreak, HCV transmission was mainly patient to patient via healthcare workers' hands. However, transmission via dialysis machines because of possible contamination of internal components could not be excluded.

Molecular characterization of HCV in a Swedish county over 8 years (2002-2009) reveals distinct transmission patterns

Background

Hepatitis C virus (HCV) is a major public health concern and data on its molecular epidemiology in Sweden is scarce. We carried out an 8-year population-based study of newly diagnosed HCV cases in one of Sweden's centrally situated counties, Södermanland (D-county). The aim was to characterize the HCV strains circulating, analyze their genetic relatedness to detect networks, and in combination with demographic data learn more about transmission.

Methods

Molecular analyses of serum samples from 91% (N=557) of all newly notified cases in D-county, 2002–2009, were performed. Phylogenetic analysis (NS5B gene, 300 bp) was linked to demographic data from the national surveillance database, SmiNet, to characterize D-county transmission clusters. The linear-by-linear association test (LBL) was used to analyze trends over time.

Results

The most prevalent subtypes were 1a (38%) and 3a (34%). Subtype 1a was most prevalent among cases transmitted via sexual contact, via contaminated blood, or blood products, while subtype 3a was most prevalent among people who inject drugs (PWIDs). Phylogenetic analysis revealed that the subtype 3a sequences formed more and larger transmission clusters (50% of the sequences clustered), while the 1a sequences formed smaller clusters (19% of the sequences clustered), possibly suggesting different epidemics.

Conclusion

We found different transmission patterns in D-county which may, from a public health perspective, have implications for how to control virus infections by targeted interventions.

Phylogenetic analysis of hepatitis C virus strains and risk factors associated with infection and viral subtypes among Iranian patients

Hepatitis C virus (HCV) has infected approximately 170 million people worldwide. While the seroprevalence of anti-HCV antibody among Iranian blood donors is 0.13%, HCV infection is prevalent in 59-80% of Iranian injecting drug users. One hundred seventy-eight anti-HCV positive patients were referred to the Gastroenterology Department at the Taleghani Hospital (Tehran, Iran) between June 2007 and June 2012. Out of 178 samples, 142 were positive for HCV-RNA. HCV subtypes were determined using phylogenetic analysis of the NS5B or 5'UTR/core regions. Of 142 viremic patients, 71 (50%) were infected with HCV subtype 1a, 43 (30.3%) with subtype 3a, 20 (14.1%) with subtype 1b, 3 (2.1%) with subtype 4d, 2 (1.4%) with subtype 4a, 1 (0.7%) with subtype 2b, and 1 (0.7%) with subtype 6a. Interestingly, genetic analysis of a sub-genomic fragment from one patient identified a non-subtypeable HCV genotype-3 strain. There was a significant association between HCV subtype and a history of injecting drug use (P = 0.003). Subtype 3a was predominant among patients with such a history. Injecting drug use was associated with younger age (P < 0.001). HCV subtype was also significantly associated with a history of upper gastrointestinal endoscopy (P = 0.02). Subtype 1a was more frequent among patients with such a history. In addition, history of upper gastrointestinal endoscopy was significantly associated with older age (P = 0.002). In conclusion, while HCV subtype 1a is predominant among infected Iranian individuals, subtype 3a is predominant among Iranian injecting drug users.

A new subtype of hepatitis C virus genotype 3: analysis of available evidence

BACKGROUND

Hepatitis C virus (HCV) is one of the leading causes of chronic liver disease. Seven genotypes and more than 80 subtypes have been identified for HCV so far. To date, 10 subtypes (3a to 3i; and 3k) of HCV genotype 3 have been identified. In 2006, two HCV isolates were reported from Iran that belonged to a new subtype of genotype 3. However, considering the consensus proposal for HCV genotype nomenclature, the available sequences of the new subtype did not correspond to the regions that are required to be analyzed prior to subtype assignment. During a study on the molecular epidemiology of HCV in Iran, an HCV isolate (FSM165) which seemed to belong to a new subtype of genotype 3 was obtained from a patient residing in Tehran, Iran.

OBJECTIVES

The aim of this study was to assess the relatedness of isolate FM165 together with several sequences retrieved from the database to the new HCV-3 subtype reported from Iran in 2006.

MATERIALS AND METHODS

Various parts of the genome including the core/E1 region and two segments of the NS5B region were amplified and sequenced for isolate FSM165. Furthermore, using the Basic Local Alignment Search Tool (BLAST), the HCV database was searched for sequences that had a high level of similarity with sequences of FSM165 isolate and such sequences were retrieved from the database. To investigate the relatedness of isolate FSM165 and also the retrieved sequences to a new HCV-3 subtype reported previously, phylogenetic analyses were performed using the Kimura two-parameter model and the neighbor joining method.

RESULTS

Phylogenetic analysis of the partial NS5B region demonstrated the relatedness of isolate FSM165 to the new subtype reported from Iran in 2006. Moreover, some core/E1 and NS5B sequences that had a high level of similarity with FSM165 isolate were found through searching the HCV database. These sequences were previously either misclassified or could not be accurately classified. Phylogenetic analyses showed that all of the described sequences belonged to the new subtype of HCV genotype 3.

CONCLUSIONS

Data suggests that the new subtype has a vast geographical distribution in Iran. The core/E1 and the NS5B sequences described in this paper can be used as references for the new HCV-3 subtype in future studies.

Patient-to-Patient Transmission of Hepatitis C at Iranian Thalassemia Centers Shown by Genetic Characterization of Viral Strains

BACKGROUND

Hepatitis C is prevalent among thalassemia patients in Iran. It is mainly transfusion mediated, in particular among patients treated before 1996 when blood screening was introduced.

OBJECTIVES

The current study aimed to investigate why patients still seroconvert to anti-HCV in Iranian thalassemia centers.

PATIENTS AND METHODS

During 2006-2007 sera were sampled from 217 anti-HCV positive thalassemia patients at nine thalassemia centers in Tehran and Amol city, where 34 (16%) patients had been infected after 1996. The HCV subtype could be determined by sequencing and phylogenetic analysis of partial NS5B and/or 5׳NCR-core region in 130 strains.

RESULTS

1a (53%) was predominant followed by 3a (30%), 1b (15%), and one strain each of 2k, 3k and 4a. Phylogenetic analysis revealed 19 clades with up to five strains diverging with less than six nucleotides from each other within subtypes 1a and 3a. Strains in seven clades were from nine patients infected between 1999 and 2005 and similar to strains from eight patients infected before 1996, indicating ongoing transmission at the centers. Further epidemiological investigation revealed that 28 patients infected with strains within the same clade had frequently been transfused at the same shift sitting on the same bed. An additional eight patients with related strains had frequently been transfused simultaneously in the same room.

CONCLUSIONS

The results suggest nosocomial transmission at these thalassemia centers both before and after the introduction of blood screening. Further training of staff and strict adherence to preventive measures are thus essential to reduce the incidence of new HCV infections.

Hepatitis C transmission due to contamination of multidose medication vials: summary of an outbreak and a call to action

In May 2001, The New York City Department of Health and Mental Hygiene was informed of a cluster of 4 patients treated at an outpatient gastroenterology center who developed acute hepatitis C virus infection. An investigation identified a total of 12 clinic-associated hepatitis C virus transmissions and the outbreak and was traced to unsafe handling of multidose anesthetic vials and possible re-use of contaminated needles. This report typifies the types of outbreaks that continue to occur despite safe injection guidelines.

Genetic history of hepatitis C virus in Venezuela: high diversity and long time of evolution of HCV genotype 2

BACKGROUND

The subtype diversity of the hepatitis C virus (HCV) genotypes is unknown in Venezuela.

METHODOLOGY/PRINCIPAL FINDINGS

Partial sequencing of the NS5B region was performed in 310 isolates circulating in patients from 1995 to 2007. In the samples collected between 2005 and 2007, HCV genotype 1 (G1) was the most common genotype (63%), composed as expected of mainly G1a and G1b. G2 was the second most common genotype (33%), being G2a almost absent and G2j the most frequent subtype. Sequence analysis of the core region confirmed the subtype assignment performed within the NS5b region in 63 isolates. The complete genome sequence of G2j was obtained. G2j has been described in France, Canada and Burkina Fasso, but it was not found in Martinique, where several subtypes of G2 circulate in the general population. Bayesian coalescence analysis indicated a most recent common ancestor (MRCA) of G2j around 1785, before the introduction of G1b (1869) and G1a (1922). While HCV G1a and G1b experienced a growth reduction since 1990, coincident with the time when blood testing was implemented in Venezuela, HCV G2j did not seem to reach growth equilibrium during this period.

CONCLUSIONS/SIGNIFICANCE

Assuming the introduction of G2j from Africa during the slave trade, the high frequency of G2j found in Venezuela could suggest: 1- the introduction of African ethnic groups different from the ones introduced to Martinique or 2- the occurrence of a founder effect. This study represents an in-depth analysis of the subtype diversity of HCV in Venezuela, which is still unexplored in the Americas and deserves further studies.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

Pegylated interferon alpha-2a for treatment of chronic HCV infection in hemodialysis patients: a single Saudi center experience

INTRODUCTION

Chronic hepatitis C infection is common among patients on dialysis. While the associated liver disease is usually relatively mild during dialysis, disease progression can accelerate due to immunosuppression following kidney transplantation, and interferon therapy after transplantation stimulates graft rejection. Pegylated interferon and ribavirin are now the recommended treatment for chronic hepatitis C virus in patients without renal failure. However, until now, there has been relatively little information on the efficacy and tolerability of pegylated interferon in dialysis patients.

AIM OF THE WORK

To evaluate the response to pegylated interferon alpha-2a in chronic hepatitis C-infected patients on chronic hemodialysis.

PATIENTS AND METHODS

This controlled study included 28 patients with end-stage renal disease who had been on dialysis in the Prince Salman Center for Kidney Disease for more than 6 months and tested positive for HCV RNA on repeated occasions. Thirteen patients were treated with pegylated interferon alpha-2a therapy (of which three were also receiving ribavirin), and the remaining fifteen served as controls. Viral genotyping and both qualitative and quantitative PCR were carried out before starting therapy. Treatment was continued for 48 weeks. After 24 weeks of treatment, the biochemical and virological responses were evaluated. Biochemical response was evaluated at the end of the treatment, with sustained virological response (SVR) being evaluated 24 weeks later. The side effects were monitored throughout the treatment period.

RESULTS

All patients in the treatment group completed 48 weeks of therapy without any drop out. Their mean age was 43.38 ± 11.62 years. After 24 weeks of therapy, 10 patients (76%) were initial responders, while 3 patients (24%) were resistant. Six months after termination of therapy, 9 patients (69%) were sustained responders, while one patient relapsed. Their ALT and AST dropped from 55.78 ± 33.79 IU/dl and 34.04 ± 19.58 IU/dl before starting therapy to 27.22 ± 16.54 IU/dl and 18.88 ± 12.28 IU/dl after termination (P = .06 and .08, respectively). Their mean hemoglobin (Hb) level dropped from 11.05 ± 1.43 to 9.48 ± 1.24 g/dl (P = 0.3), and white blood cell count (WBC) dropped from 6.82 ± 2.6 × 10(3)/mm(3) to 4.1 ± 2.34 × 10(3)/mm(3); (P = 0.57). Platelet count fell from 194.56 ± 129.78 × 10(3)/mm(3) to (152.33 ± 107.66 × 10(3)/mm(3); P = 0.39). When initial responders (n = 10) were compared to resistant patients (n = 3), the only observable difference was higher ALT and AST levels in resistant patients. Pegylated interferon alpha-2a was well tolerated, and none of the patients stopped interferon because of hematological side effects while dose modification was carried out in most of the patients. All three patients who received combination therapy from the start were sustained responders. None of the patients in the control group seroconverted to HCV negative status during the study period.

CONCLUSION

Pegylated interferon alpha-2a was well tolerated among our hemodialysis patients. Hematological disturbances appeared to be the most important adverse effects. At the end of therapy a response rate of up to 76%, with 69% sustained response, can be obtained with pegylated interferon alpha-2a therapy.

Infection control guidelines for prevention of health care-associated transmission of hepatitis B and C viruses

Viral hepatitis was first identified as an occupational hazard for health care workers more than 60 years ago. For the past few decades, hepatitis B has been one of the most significant occupational infectious risks for health care providers. With the increasing prevalence of hepatitis C infections around the world, occupational transmission of this flavivirus from infected patients to their providers has also become a significant concern. Several factors influence the risk for occupational blood-borne hepatitis infection among health care providers, among them: the prevalence of infection among the population served, the infection status of the patients to whom workers are exposed (ie, the source patient's circulating viral burden), the types and frequencies of parenteral and mucosal exposures to blood and blood-containing body fluids, and whether the patient or provider has been immunized with the hepatitis B vaccine. This article reviews patient-to-provider, patient-to-patient, and provider-to-patient transmission of hepatitis B and C in the health care setting. Current prevention strategies, precautions, and guidelines are discussed.

Molecular epidemiology of health care-associated transmission of hepatitis B and C viruses

The term "molecular epidemiology" has been ascribed to a host of different activities that involve gene-sequence analysis. Some examples of molecular epidemiology include modeling exercises of phylogenetic trees to reconstruct epidemics; studies of the evolution of hepatitis C virus (HCV); rates of nucleotide substitution in the hepatitis B virus (HBV) surface (S) gene; variations in the core promoter/pre-core/core region of HBV genotype C from different sources; analysis of HBV surface antigen mutations; molecular clock analyses of the short-term evolution of HCV; and analyses of clades and surface antigen polymorphisms of HBV. However, for most epidemiologists molecular epidemiology of viral hepatitis usually refers to studies of gene-sequence homology in HBV or HCV recovered from people in the community or an institution that allows better characterization and assignment of related clusters of infection.

Evidence of recombination in Hepatitis C Virus populations infecting a hemophiliac patient

Background/Aim

Hepatitis C virus (HCV) infection is an important cause of morbidity and mortality in patients affected by hereditary bleeding disorders. HCV, as others RNA virus, exploit all possible mechanisms of genetic variation to ensure their survival, such as recombination and mutation. In order to gain insight into the genetic variability of HCV virus strains circulating in hemophiliac patients, we have performed a phylogenetic analysis of HCV strains isolated from 10 patients with this kind of pathology.

Methods

Putative recombinant sequence was identified with the use of GARD program. Statistical support for the presence of a recombination event was done by the use of LARD program.

Results

A new intragenotypic recombinant strain (1b/1a) was detected in 1 out of the 10 hemophiliac patient studied. The recombination event was located at position 387 of the HCV genome (relative to strain AF009606, sub-type 1a) corresponding to the core gene region.

Conclusion

Although recombination may not appear to be common among natural populations of HCV it should be considered as a possible mechanism for generating genetic diversity in hemophiliacs patients.

Hepatitis C: sexual or intrafamilial transmission? Epidemiological and phylogenetic analysis of hepatitis C virus in 24 infected couples

The role of sexual or intrafamilial transmission of hepatitis C is controversial. A phylogenetic analysis was performed on the non-structural region 5B of the hepatitis C virus (NS5B-HCV). High percentages of homology (mean of 98.3%) were shown between the couples. Twenty (83.3%) of the 24 men but only two of the women (8.3%) reported having had sexually transmitted diseases during their lives. The risk factors for HCV acquisition were blood transfusion (10 couples), use of illegal injected drugs (17), use of inhalants (15), acupuncture (5) and tattoos (5). The shared use of personal hygiene items included toothbrushes between six couples (25%), razor blades between 16 (66.7%), nail clippers between 21 (87.5%) and manicure pliers between 14 (58.3%). The high degree of similarity of the hepatitis C virus genome supports the hypothesis of hepatitis C virus transmission between these couples. The shared use of personal hygiene items suggests the possibility of intrafamilial transmission of infection.

Absence of intrafamilial transmission of hepatitis C virus and low risk for sexual transmission in rural central Africa indicate a cohort effect

BACKGROUND

Intrafamilial and sexual transmission of hepatitis C virus (HCV) are still being debated, and little is known about such transmission in central Africa.

OBJECTIVE

To examine the rate of intrafamilial transmission of HCV between patients and their household members.

STUDY DESIGN

A cross-sectional study was conducted in Dienga, a remote village in Gabon, involving 195 household members of 14 index cases of HCV infection. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for antibody to HCV by an enzyme immunoassay (Monolisa anti-HCV plus version 2). Positive samples were tested for HCV RNA and genotyped by amplification and phylogenetic analysis of a fragment of the NS5B gene.

RESULTS

HCV antibody was found in 13/195 (6.7%) household contacts, comprising 5/14 (35.7%) sexual partners and 8/114 (7%) relatives. None of the children of index patients tested positive. HCV RNA was detected in only five household members with HCV antibody. The same genotypes were found in only two of five couples, both couples being sexual partners. Parenteral risk factors were not more likely to be reported by people positive for HCV antibody than by those who were negative. Age over 50 years was the only independent predictor of positivity for HCV antibody.

CONCLUSIONS

This study indicates, as previously suggested, that the spread of HCV in central Africa is due to a cohort effect, with previous, possibly iatrogenic, transmission rather than intrafamilial or sexual transmission.

Sexual transmission of hepatitis C

It is generally agreed that the hepatitis C virus (HCV) can be efficiently transmitted parenterally, although data on viral transmission by sexual or non-sexual intrafamilial contact are conflicting. Since data collection began in 1989, the first study dealt with the risk of sexual transmission among multiple sex partners. Other investigations followed, emphasizing that risk increases in specific groups such as patients co-infected with HIV and HBV, sex workers, homosexuals, illicit drug users and patients attended at sexually transmittable disease clinics. The question arises as to what might be the risk for monogamous heterosexuals in the general population, in which one of the partners has HCV? The literature provides overall rates that vary from zero to 27%; however, most studies affirm that the chances of sexual transmission are low or almost null, with rates for this mode fluctuating from zero to 3%. Intrafamilial transmission is strongly considered but inconclusive, since when mentioning transmission between sex partners within the same household, specific situations also should be considered, such as the sharing of personal hygiene items, like razorblades, toothbrushes, nail clippers and manicure pliers, which are important risk factors in HCV transmission. In this review, we discuss the hypotheses of sexual and/or intrafamilial transmission.

Genetic characterization of hepatitis C virus strains in Estonia: fluctuations in the predominating subtype with time

During the last decade, there has been a dramatic increase in intravenous drug use in young adults in Estonia with an increased incidence of both hepatitis B and C as a consequence. Since genetic data are limited regarding hepatitis C virus (HCV) strains in Estonia, the aim of the study was to characterize HCV strains in different risk groups to determine their relatedness to strains from other geographical regions. Three hundred fifty-three anti-HCV positive sera collected during 1994-2004 from hospitalized patients, blood donors and health care workers were used as source of HCV RNA. Two hundred nine (59%) of the sera were positive for HCV RNA by PCR directed to the 5'-UTR region. For 174 strains the HCV subtype was determined by analyses of the NS5B and/or the 5'UTR-core regions. 1b (71%) was the most common subtype followed by 3a (24%), 2c (2%), 1a (1%), and 2a (1%). The 1b and 3a strains were similar to strains from other regions of the former USSR. Within genotype 1b there were several HCV lineages. However, for 3a there seemed to be two separate introductions into Estonia. There was a relative shift from subtype 1b to 3a in 1999-2000 with a further replacement of 3a with 1b in intravenous drug users in 2001 and onwards (P < 0.05). However, both subtypes were found to co-circulate in the community independent of risk factors. One patient was infected with the 2k/1b recombinant presumed to originate from St. Petersburg being the first isolate of this recombinant recovered outside Russia.

Improvement of hepatitis C virus (HCV) genotype determination with the new version of the INNO-LiPA HCV assay

Hepatitis C virus (HCV) isolates have been classified into six main genotypes. Genotyping methods, and especially the widely used line probe assay (LiPA), are frequently based on the 5'-untranslated region (5'UTR). However, this region is not appropriate for discriminating HCV strains at the subtype level and for distinguishing many genotype 6 samples from genotype 1. We investigated the capacity of a novel LiPA (Versant HCV Genotype 2.0 assay) based on the simultaneous detection of 5'UTR and Core regions for genotypes 1 and 6 to provide correct HCV genotypes (characterized with a phylogenetic analysis) in a set of HCV strains mainly encountered in Western countries. The improvement was assessed by comparing the results to those obtained with the previous version of the assay. Of the 135 tested samples, 64.7% were concordant for genotype group and subtype with sequencing reference results using the Versant HCV Genotype 2.0 assay versus 37.5% with the previous version. The yield was mainly related to a better characterization of genotype 1, since the accuracy, tested in 62 genotype 1 samples, increased from 45.2% with the first version to 96.8% with the new one. However, this new version necessitates a specific PCR and could no longer be used after 5'UTR PCR used for current HCV infection diagnosis. Moreover, the information provided by 5'UTR hybridization is not reliable for correctly identifying the diversity within genotypes 2 and 4. Thus, the Versant HCV Genotype 2.0 assay remains a useful tool for clinical practice when only the discrimination between major HCV genotypes is necessary.

Determining the source of nosocomial transmission in hemodialysis units in Tunisia by sequencing NS5B and E2 sequences of HCV

Hepatitis C virus infection is a significant problem in hemodialysis units. HCV is very variable genetically with six genotypes. Clinical and epidemiological investigation of a new infection requires the determination of both the genotype and the strain of the HCV involved. A prospective, epidemiologic study of 395 dialysis patients in Tunisia was conducted from November 2001 to November 2003 to identify the source of nosocomial transmission using phylogenetic analysis of NS5b and E2 sequences. Hepatitis C infection was diagnosed by screening for anti-HCV antibodies and HCV RNA in sera using third generation ELISA and a qualitative RT-PCR assay. HCV strains were genotyped by sequencing the NS5b region. The genetic relatedness of the HCV strains was studied by sequencing the NS5b and the HVR-1 regions of the HCV genome. Two de novo cases of HCV infection were detected during the follow-up. One of them has been described previously. The case described in this study occurred in a center in which 12 patients were already infected with HCV strains belonging to genotypes 1b (n = 8) and 1a (n = 4). Phylogenetic analysis of the NS5b region from the HCV strains circulating in this center disclosed four clusters, confirmed by analysis of the HVR-1 region, providing strong evidence for nosocomial infection. Epidemiological data showed that these patients were dialyzed during the same shift and in the same area. Phylogenetic analysis of NS5b sequences is useful for determining the HCV genotype and providing evidence of nosocomial transmission.

Genetic diversity and evolution of hepatitis C virus in the Latin American region

Hepatitis C virus (HCV) has been the subject of intense research and clinical investigations, as a consequence of the recognition of its major role in human disease. HCV evolution is a highly dynamic process. HCV exploits all known mechanisms of genetic variation, such as recombination and mutation, to ensure its survival. Like most RNA viruses, HCV circulates in vivo as a complex population of different but closely related variants, commonly referred to as a quasi species. This work describes the genetic variability of HCV in Latin America, with special emphasis on its diversification and recombination in this area of the world, and discusses how our knowledge of these issues can contribute to its control.

Hepatitis C virus infection among dialysis patients in Tunisia: incidence and molecular evidence for nosocomial transmission

In order to study the incidence of hepatitis C virus (HCV) infection in Tunisian haemodialysis patients and detect its nosocomial transmission, 395 patients were enrolled in a prospective study (November 2001-2003). HCV serological and virological status was determined initially using, respectively a third generation ELISA and an RT-PCR qualitative assay. The genotype of the HCV isolates was determined by sequencing NS5B region. The issue of nosocomial transmission was addressed by sequencing the HVR-1 region of the E2 gene. About 20% of the patients had anti-HCV antibodies and HCV-RNA was detected in 73% of the anti-HCV positive patients. Two cases of de novo HCV infection were identified in two dialysis centers, during virological follow-up of patients susceptible to HCV infection. The incidence of de novo HCV infection was 0.5%. Determining the genotypes in the first center disclosed that all HCV-positive patients were infected with genotype 1b; sequencing of the HVR-1 region of the E2 gene provided strong evidence that the isolate from the newly infected patient and another infected dialysis patient were closely related, confirming nosocomial contamination. The investigation of the second center is pending. Besides, one patient with negative HCV serology had detectable HCV-RNA at the beginning of the study. This case had HCV genotype 1b, two other infected dialysis patients in the same unit had HCV genotypes 4k and 3a; thus precluding nosocomial transmission. Thanks to molecular and phylogenetic methods, one case of nosocomial HCV transmission in haemodialysis was confirmed. Epidemiological investigation suggested nosocomial transmission via the medical and/or nursing staff.

A cluster of hepatitis C virus infections associated with ozone-enriched transfusion of autologous blood in Rome, Italy

OBJECTIVE

To describe an outbreak of hepatitis C virus (HCV).

DESIGN

Retrospective cohort study.

SETTING

Outpatient department of a hospital in Rome, Italy.

PATIENTS

All 42 patients exposed to ozone therapy by autohemotherapy or intramuscular injection from January to June 2001.

METHODS

Epidemiologic investigation, serologic analysis, and virus genotyping.

RESULTS

Thirty-one (74%) of the patients agreed to participate in the study. Three (9.7%) had symptoms of HCV infection. This incidence rate was higher than the rate of 1.4 per 100,000 per year in the regional population. Six patients were positive for HCV antibodies and HCV RNA for a prevalence rate of 19.4%, which was much higher than the estimate of 0.9% in the population. Virus genotype 1b was found in two case-patients (one symptomatic) and 2c in four case-patients (two symptomatic), one of whom was known to have an HCV infection since 1986 and could have been the source of infection. The infected patients were all being exposed to ozone-enriched transfusions of autologous blood. Although the specific mode of transmission between patients was not detected, transmission probably occurred during one of the three busiest therapeutic sessions in the 6-month period.

CONCLUSIONS

Transmission of HCV infection may occur during medical procedures with limited bleeding. Standard precautions must be applied in any healthcare setting; restricting the number of individuals treated during each therapeutic session could be an effective way of avoiding accidental transmission of infection.

Characterization of HCV strains in an oncohematological pediatric department reveals little horizontal transmission but multiple introductions by un-screened blood products in the past

Because several children were found infected with hepatitis C virus (HCV) at a pediatric oncohematological department in Vilnius, 474 children were tested for anti-HCV. Fifty-eight percent of 96 children treated with blood and plasma products manufactured before the introduction of anti-HCV screening of blood in Lithuania in 1994 were positive for anti-HCV versus 3.4% of those treated after 1994. The possible route of transmission for 45 of these was investigated by phylogenetic analyses within the NS5B region. Children treated before 1995 were infected with a multiplicity of strains of different subtypes, predominantly 1b found in 21 cases, 3a in 5 cases, 2 in 3 cases, 1a in 1 case, and not subtypeable genotype 1 strains in 2 cases. Children who had received blood products after 1994 were infected with only two subtypes, 1b in six and 3a in seven. Genetic analysis showed multiple introductions of HCV before 1995 and that horizontal spread between patients had occurred only to a minor extent at the department. However, two transmission chains involved children treated before 1995. Another chain involved five children treated after 1994. Since the most important risk factor for acquiring hepatitis C was blood products manufactured before the introduction of donor screening for anti-HCV, the spread between children would not have been revealed without molecular tools. These and the background strains provide the first reported sequence data on Lithuanian HCV strains. In general, these were shown to form autochthonous clades, except the 3a strains that were related to strains from the former USSR.

Different seroprevalence and molecular epidemiology patterns of hepatitis C virus infection in Italy

The epidemiological picture of hepatitis C virus (HCV) infection in the general population is largely unknown, even in developed countries. The aim of this study was to estimate the prevalence and genotype distribution of HCV amongst a large sample of the Italian general population. A total of 3,577 serum samples were collected and screened for anti-HCV antibodies. ELISA and RIBA tests were used to assess the presence of anti-HCV. NS5b region sequencing was performed for molecular characterization. Of 3,577 tested sera, 95 (2.7%) were anti-HCV positive and a genome was detected and sequenced in 50 sera. The age-adjusted prevalence was 4.4%. Seroprevalence increased with age, following a North-South gradient, and increased steeply between the 15 and 30 and 31-45 age groups. Subtype 1b showed the highest prevalence in all geographical areas and age groups, followed by subtypes 2c (detected mainly in the elderly population in Southern Italy), 4a/d, and 3a (detected exclusively in adults) and 1a. These findings confirm that Central and Southern Italy are hyperendemic areas. The high prevalence observed in adults over age 30 is mainly attributable to an increase in 1b-prevalence but also to subtypes 2c- and 3/4-infections. Age-specific prevalence data and molecular characterization of the virus suggest that two transmission patterns co-exist in Italy: one characterized by subtype 1b and 2c infections, mainly in adults older than 60 years, and the other by subtype 3 and 4 infections, mainly in the 31-60 year age group, and consistent with intravenous drug use and immigration.

Global epidemiology of hepatitis C virus infection

Hepatitis C virus (HCV) is a major cause of liver disease worldwide and a potential cause of substantial morbidity and mortality in the future. The complexity and uncertainty related to the geographic distribution of HCV infection and chronic hepatitis C, determination of its associated risk factors, and evaluation of cofactors that accelerate its progression, underscore the difficulties in global prevention and control of HCV. Because there is no vaccine and no post-exposure prophylaxis for HCV, the focus of primary prevention efforts should be safer blood supply in the developing world, safe injection practices in health care and other settings, and decreasing the number of people who initiate injection drug use.

Transmission of human hepatitis C virus from patients in secondary cells for long term culture

Infection by human hepatitis C virus (HCV) is the principal cause of post-transfusion hepatitis and chronic liver diseases worldwide. A reliable in vitro culture system for the isolation and analysis of this virus is not currently available, and, as a consequence, HCV pathogenesis is poorly understood. We report here the first robust in vitro system for the isolation and propagation of HCV from infected donor blood. This system involves infecting freshly prepared macrophages with HCV and then transmission of macrophage-adapted virus into freshly immortalized B-cells from human fetal cord blood. Using this system, newly isolated HCV have been replicated in vitro in continuous cultures for over 130 weeks. These isolates were also transmitted by cell-free methods into different cell types, including B-cells, T-cells and neuronal precursor cells. These secondarily infected cells also produced in vitro transmissible infectious virus. Replication of HCV-RNA was validated by RT-PCR analysis and by in situ hybridization. Although nucleic acid sequencing of the HCV isolate reported here indicates that the isolate is probably of type 1a, other HCV types have also been isolated using this system. Western blot analysis shows the synthesis of major HCV structural proteins. We present here, for the first time, a method for productively growing HCV in vitro for prolonged periods of time. This method allows studies related to understanding the replication process, viral pathogenesis, and the development of anti-HCV drugs and vaccines.

Comparison of hepatitis C virus NS5b and 5' noncoding gene sequencing methods in a multicenter study

A national evaluation study was performed in 11 specialized laboratories with the objective of assessing their capacities to genotype hepatitis C virus (HCV) and define the applicability of a given genotyping method. The panel consisted of 14 samples positive for HCV RNA of different genotypes (including 3 samples with two different artificially mixed genotypes) and 1 HCV-negative sample. Seventeen sets of data were gathered from the 11 participating laboratories. The sensitivities ranged from 64.3 to 100% and from 42.7 to 85.7% for the methods that used sequencing of the NS5b region and the 5' noncoding (5' NC) region, respectively. When the data for the artificially mixed samples were excluded, NS5b genotyping gave correct results for 80% of the samples, 1.7% of the samples were misclassified, and 18.3% of the samples had false-negative results. By 5' NC-region genotyping methods, 58.3% of the results were correct, 29.7% were incomplete, 8.3% were misclassifications, 1.2% were false positive, and 2.4% were false negative. Only two procedures based on NS5b sequencing correctly identified one of the three samples with mixtures of genotypes; the other methods identified the genotype corresponding to the strain with the highest viral load in the sample. Our results suggest that HCV 5' NC-region genotyping methods give sufficient information for clinical purposes, in which the determination of the subtype is not essential, and that NS5b genotyping methods are more reliable for subtype determination, which is required in epidemiological studies.

Molecular epidemiology of hepatitis C virus in Iran as reflected by phylogenetic analysis of the NS5B region

Hepatitis C virus (HCV) subtypes were determined in 125 Iranian patients by phylogenetic analysis within the NS5B or 5'-UTR/core regions. Subtypes 1a and 3a were predominant accounting for 47 and 36%, whereas 1b and 4 accounted for 8 and 7%. This subtype distribution differs from that of Turkey and Pakistan, where subtypes 1b and 3a dominate and also from neighbouring Arabic countries where subtype 4 is the prevalent genotype. The Iranian 1a and 3a strains formed subclusters in the dendrogram indicating that these subtypes are indigenous to Iran. In contrast, the 1b strains intermixed with strains derived worldwide. Subtype 1a was frequent in South Iran (70%), while 3a was more prevalent in North-West Iran (83%), a region with a high proportion of Turkish inhabitants. Patients infected by blood products had more frequently subtype 1a (57%), while younger drug users had more frequently subtype 3a (54%). Genotype 4 was over-represented among haemodialysis patients in Tehran. One strain, most similar to genotype 5, was highly divergent in the NS5B region and further analysis is needed to assess the systematic status of this strain. In half of the patients with unknown source of infection only the 5'-UTR could be amplified, most of which were from North-West Iran and from patients younger than those with unknown source of infection with typable strains, mean age 29 versus 43 years. In conclusion, the NS5B sequence data revealed population based subtype patterns in Iran, the further study of which may help to understand the molecular epidemiology of HCV in a low-endemic area.

Confirmation of nosocomial hepatitis C virus infection in a hemodialysis unit

OBJECTIVES

To investigate a hepatitis C virus (HCV) outbreak in a hemodialysis unit and determine the source of transmission.

METHODS

We have prospectively investigated the epidemiology of hemodialysis-related HCV infection in a single unit since 1989. In September 2000, acute hepatitis C (AH-C) was diagnosed in 5 patients by alanine aminotransferase elevation and HCV genotype 1b viremia without antibody to HCV. We surveyed the epidemiologic situation and performed polymerase chain reaction sequence analysis of the HCV 5'-noncoding (5'NC) region in the patients for comparison with 9 patients with chronic HCV genotype 1b viremia.

RESULTS

Sequence analysis of the 5'NC region showed the consistency in the 5 independent clones from each AH-C patient and those from each chronic HCV viremia patient and no quasispecies over time in the clones of any of 14 analyzed patients. All AH-C patients had the same sequencing of the 6 variations in the region with the only other patient. A saline ampoule, used for heparin solution during hemodialysis, had a recap function. It was difficult to determine whether the ampoule was new or had already been used. The source-patient often underwent hemodialysis before the AH-C patients and most of their hemodialysis-related medicine was prepared during the source-patient's treatment. These findings suggested a high possibility that the AH-C patients shared a single heparin-saline solution ampoule contaminated by HCV from the source-patient.

CONCLUSION

Nosocomial HCV infection occurred as a result of poor infection control practice when a patient with chronic HCV viremia received treatment prior to other hemodialysis patients.

Evidence of intratypic recombination in natural populations of hepatitis C virus

Hepatitis C virus (HCV) has high genomic variability and, since its discovery, at least six different types and an increasing number of subtypes have been reported. Genotype 1 is the most prevalent genotype found in South America. In the present study, three different genomic regions (5'UTR, core and NS5B) of four HCV strains isolated from Peruvian patients were sequenced in order to investigate the congruence of HCV genotyping for these three genomic regions. Phylogenetic analysis using 5'UTR-core sequences found strain PE22 to be related to subtype 1b. However, the same analysis using the NS5B region found it to be related to subtype 1a. To test the possibility of genetic recombination, phylogenetic studies were carried out, revealing that a crossover event had taken place in the NS5B protein. We discuss the consequences of this observation on HCV genotype classification, laboratory diagnosis and treatment of HCV infection.

Genomic and phylogenetic analysis of hepatitis C virus isolates: a survey of 535 strains circulating in southern France

The present study examines the distribution of Hepatitis C virus (HCV) genotypes in Marseille, France in 2001-2002 and evaluates the efficiency of two in house direct sequence PCR protocols based on 5'NC analysis or NS5B analysis. By 5'NC sequencing, the distribution of 535 HCV strains derived from patients attending gastroenterology and AIDS referral centers, or dialysis units was as follows: 33% were infected by genotype 1a; 26% by 1b; 7% by 2; 22% by 3a; 10.7% by 4. In univariate analysis, HCV distribution was associated with age and source of infection, whereas in multivariate analysis only injecting drug use was an independent determinant for genotype distribution. Among the 535 specimens submitted to 5'NC direct sequencing, 18% could not be classified accurately into subtypes. A subset of 187 samples was amplified efficiently and sequenced by targeting the NS5B region of the viral genome. The two methods yielded concordant results in 70% of cases. Specimens unsubtypeable or misclassified most frequently by 5'NC analysis were type 1b and subtypes 2a/2c and 4a/4c. The data show that 5'NC direct sequence analysis is a sensitive method to identify genotypes in all cases, but that it can lead to subtyping misclassification (in particular, subtype 1b and 1a) or doubtful results (in particular subtypes 2a/2c and 4a/4c). Conversely, NS5B direct sequence assay, based on phylogenetic analysis, allowed better discrimination between subtypes. These two approaches are complementary and should be made available in clinical laboratories to ensure a reliable survey of HCV strains.

Managing occupational risks for hepatitis C transmission in the health care setting

Hepatitis C virus (HCV) infection is a significant contemporary health problem in the United States and elsewhere. Because it is primarily transmitted via blood, hepatitis C infection presents risks for both nosocomial transmission to patients and occupational spread to health care workers. Recent insights into the pathogenesis, immunopathogenesis, natural history, and treatment of infection caused by this unique flavivirus provide a rationale for the use of new strategies for managing occupational hepatitis C infections when they occur. This article reviews this developing information. Recently published data demonstrate success rates in the treatment of "acute hepatitis C syndrome" that approach 100\%, and although these studies are not directly applicable to all occupational infections, they may provide important clues to optimal management strategies. In addition, the article delineates approaches to the prevention of occupational exposures and also addresses the difficult issue of managing HCV-infected health care providers. The article summarizes currently available data about the nosocomial epidemiology of HCV infection and the magnitude of risk and discusses several alternatives for managing exposure and infection. No evidence supports the use of immediate postexposure prophylaxis with immunoglobulin, immunomodulators, or antiviral agents. Based on the very limited data available, the watchful waiting and preemptive therapy strategies described in detail in this article represent reasonable interim approaches to the complex problem of managing occupational HCV infections, at least until more definitive data are obtained.

Interferon monotherapy for dialysis patients with chronic hepatitis C: an analysis of the literature on efficacy and safety

OBJECTIVE

Hepatitis C virus (HCV) is prevalent in patients with end stage renal disease who are on dialysis. Liver disease from HCV is a cause of substantial morbidity and mortality after kidney transplantation in infected recipients. Effective treatment of chronic HCV is needed in this group of patients. We aimed to determine from the literature the efficacy and safety of interferon monotherapy in dialysis patients with chronic HCV.

METHODS

We reviewed the literature from 1986 to 2001 on the efficacy of interferon monotherapy in patients with HCV and end stage renal disease who were on dialysis. The outcomes measured were sustained viral response (SVR) and drop-out rate.

RESULTS

We reviewed 17 studies, of which 11 studies with a total of 213 patients met criteria for our analysis. Eight studies evaluated 3 million units (MU) three times/wk (t.i.w.), and three studies evaluated higher doses. The pooled SVR for 3 MU was 33% (95% CI = 21-51%). The pooled SVR for genotype 1 patients was 26% (95% CI = 15-37%). Of 152 patients in eight studies treated with 3 MU t.i.w. of interferon monotherapy, 45 patients (29.6%) discontinued therapy because of side effects.

CONCLUSIONS

Our analysis suggests that interferon monotherapy is more effective in patients on dialysis than in patients with normal renal function. Interferon monotherapy is associated with more adverse events in dialysis patients. The optimal dose and duration of interferon monotherapy and selection criteria of dialysis patients need to be studied further in clinical trials.

Hepatitis C virus subtyping by a core-envelope 1-based reverse transcriptase PCR assay with sequencing and its use in determining subtype distribution among Danish patients

A reverse transcriptase PCR (RT-PCR) assay using conserved primers deduced from the core-envelope 1 (C-E1) region of the hepatitis C virus (HCV) genome was developed for subtyping purposes. The sensitivity and specificity of this assay tested against two HCV reference panels containing genotype 1 through 5 subtypes were similar to those of an RT-PCR assay from the 5'-untranslated region (5'-UTR). The sensitivity of the RT-PCR typing assay in the more variable C-E1 region was, however, lower than that of the RT-PCR in the highly conserved 5'-UTR when testing multiple clinical samples. Thus, 71 (88%) of 81 consecutive samples from hospitalized Danish patients positive for HCV antibodies and RNA (5'-UTR) were positive also in the C-E1 RT-PCR assay. Phylogenetic analysis of the E1 sequences obtained by direct sequencing of HCV from two reference panels and 71 Danish patients allowed us to readily distinguish the subtypes. In contrast, phylogenetic analysis of their corresponding 5'-UTR sequences was able to predict only major genotypes. Three different genotypes and four subtypes were identified among Danish samples: 1a (43%), 1b (11%), 2b (6%), and 3a (39%). An isolate from a Somalian refugee was identified as a new HCV type related to Somalian isolates described as subtype 3h. The most common genotype in Denmark is genotype 1 (53%), which is the most difficult to treat. However, Denmark had the highest prevalence in Europe of subtype 3a, which responds more favorably to treatment. The described C-E1 RT-PCR with sequencing is suggested as an easy routine assay for definitive genotyping and subtyping of HCV.

Transmission of HCV infection among long-term hospitalized onco-haematological patients

Hepatitis C virus (HCV) infection is becoming a substantial problem in long-term hospitalized patients. Onco-haematological patients undergoing chemotherapy are especially prone to HCV infection. These patients are usually immunosuppressed and therefore antibodies to HCV are not produced despite the presence of HCV RNA in peripheral blood. The aim of the study was to see how often long-term hospitalized patients acquired HCV infection, and what were the possible sources and routes of virus transmission. The study involved 129 children with lymphoproliferative diseases, 36 patients with solid tumours, and 61 healthcare workers from onco-haematological wards. All were HCV RNA and anti-HCV negative at the time of first hospitalization. During a two and a half-year follow-up study among 165 onco-haematological patients, HCV RNA appeared in 87 in subsequent hospitalizations. The majority of infections were (82/87) were 1a genotype, 2 were 1b, 1 was 1a + 1b and 1 was 1a + 3a. In an attempt to establish the origin of HCV infection, healthcare workers were screened for HCV genotyping. All HCV-infected staff working on wards had the same genotype (1a). None of the staff was infected with 1b genotype. As the most prevalent genotype in Polish blood donors is 1b, HCV infection in onco-haematological patients is most likely due to horizontal transmission, probably involving genotype 1a, and potential horizontal transmission of HCV is implied by the presence of 1a genotype of HCV in saliva and urine of selected patients. Spread of hospital HCV infection among children may be facilitated by micro-injury of the skin and mucosa. Early detection of HCV RNA is important in such immunosuppressed patients, as they are not able to produce anti-HCV antibodies. This may enable the introduction of prophylactic steps to prevent the spread of HCV infection by horizontal transmission.