Molecular analysis of intraspousal transmission of hepatitis C virus

HCV transmission in industrialized countries and resource-constrained areas

HCV is a blood-borne virus transmitted by percutaneous exposure to infected blood or blood-derived body fluids. The main routes of transmission are blood transfusions, medical procedures and injection drug use. In industrialized countries, HCV transmission through blood transfusions has been virtually eliminated and iatrogenic transmission occurs only sporadically during local breaches of infection control procedures. As most new cases originate from injection drug use, harm-reduction programmes (including opiate substitution, needle exchange and health education) can greatly reduce HCV transmission. Currently, the main approach to reduce the HCV disease burden is by increasing awareness of both the public and health-care providers to hepatitis C, enhancing screening opportunities and treatment of the infected population. In resource-limited countries, the priority is reducing transmission through blood transfusions and invasive medical procedures. This approach requires training of health-care providers and also structural changes and financial investments in countries where antibody screening, disposable materials and effective sterilization procedures are not routinely available. In these countries, reducing the HCV burden has been hampered by limited access to treatment, largely owing to the cost of drugs. Access to treatment is moving up on the agenda of international and non-governmental organizations in conjunction with the future availability of highly efficacious oral drug regimens.

Sexual transmission of viral hepatitis

Identification and vaccination of adults at risk for hepatitis B virus acquisition through sexual contact is a key strategy to reduce new hepatitis B virus infections among at-risk adults. Hepatitis C has emerged as a sexually transmitted infection among men with male sex partners (MSM). Several biological and behavioral factors have been linked to hepatitis C virus transmission among MSM, including human immunodeficiency virus coinfection; participation in sexual practices that result in mucosal damage or result in exposure to blood; presence of sexually transmitted diseases (STIs), particularly ulcerative STIs; multiple/casual sex partners; and unprotected anal intercourse.

Detection of hepatitis C virus subtypes 6a, 6n, 6w and mixed infections using a modified multiplex real-time polymerase chain reaction protocol

BACKGROUND/PURPOSE

In the past few years, many new subtypes in hepatitis C virus (HCV) genotype 6 have been identified. The aim of this study was to modify the multiplex real-time polymerase chain reaction (RT-PCR) protocol and use it to determine the HCV subtypes of a group of Taiwanese injection drug users (IDUs).

METHODS

We used 76 serum specimens collected in northern Taiwan in 2008. Multiplex RT-PCR was used for HCV subtyping among those serum samples having anti-HCV antibodies. Twenty cases were randomly selected for comparison with subtyping results from Inno-LiPa II tests and phylogenetic tree analysis using NS5B sequences.

RESULTS

Multiplex RT-PCR assays showed that 60.5% (46/76) of IDUs had single HCV infection. Three out of 76 (3.9%) had double HCV infection (1b/6a, 2a/2b and 2b/6a). Besides this, 27.6% (21/76) had no HCV signal. One IDU had subtype 6n and two had subtype 6w infection. Inno-LiPa II tests misclassified all 6n and 6w cases as 1b subtype.

CONCLUSION

Our modified multiplex RT-PCR protocol can be used to support molecular epidemiological studies and laboratory diagnoses of different HCV subtypes including genotype 6.

ASSESSING THE EFFECTS OF INTRAVENOUS DRUG USE ON HEPATITIS C TRANSMISSION DYNAMICS

A mathematical model for the transmission dynamics of Hepatitis C virus (HCV) have been proposed and investigated. The model presented looks into preferential sexual contacts between intravenous drug users and non-drug users. The threshold parameters of the model are determined and stabilities analysed. Both analytic and numerical simulations show that increase in intravenous drug use in addition to sex results in an increase of HCV cases. Thus, safe sex and treatment of HCV alone are not enough to curtail the transmission of HCV. Effective control of HCV require strategies that are tailor made for intravenous drug users.

Is sexual contact a major mode of hepatitis C virus transmission?

Medical opinion varies considerably regarding the transmission of hepatitis C virus (HCV) through sexual contact. Based on the study design, representativeness of the study population, and the methods used for case ascertainment, we analyzed 80 qualifying reports regarding the evidence for or against sexual transmission. Regarding heterosexual transmission, the weight of evidence is that there is no increased risk of sexual transmission of HCV among heterosexual couples in regular relationships. This risk increases among persons with multiple sexual partners (adjusted odds ratio [aOR] 2.2-2.9), but this association may be confounded by increased likelihood of injection drug use with increased number of partners. There appears to be a real increased risk for women coinfected with human immunodeficiency virus (HIV) or other sexually transmitted infections (aOR 3.3-3.9) and especially for HIV-infected gay men who are having sex with one another compared with HIV-uninfected men (aOR 4.1-5.7). HIV-infected gay men increase their risk of such transmission in association with practices that lead to mucosal trauma (multiple sexual partners, fisting, use of sex toys) and the presence of genital ulcerative disease.

CONCLUSION

This review should inform, and not distract from, recommendations to reduce the risk of HCV transmission. Health care providers need to pay special attention to sexual transmission of HCV among HIV-infected individuals.

Acute hepatitis C in HIV-infected men who have sex with men: an emerging sexually transmitted infection

Since 2000 outbreaks of acute hepatitis C virus (HCV) among HIV-positive men who have sex with men (MSM) who denied injecting drug use have been reported from Europe, the United States, Canada and Australia. Given the burden of liver disease, in particular HCV, on the morbidity and mortality in HIV patients in the era of combination antiretroviral therapy, the rapid and significant rise in the incidence of HCV in the HIV-infected MSM population in high-income countries is alarming. This relates to a significant change in the epidemiology of HCV that has occurred, with HCV emerging as a sexually transmitted infection within this population. Work to date suggests that this permucosal HCV transmission results from high-risk sexual and noninjecting drug use behaviours, reopening the discussion on the importance of sexual transmission. Given this occurs almost exclusively in HIV-infected MSM, HIV probably has a critical role mediated either through behavioural and/or biological factors. Finally, the management of acute HCV in HIV infection is complicated by concomitant HIV infection and combination antiretroviral therapy. This review will synthesize the most recent epidemiological, immunological and management issues that have emerged as a result of the epidemic of acute HCV among HIV-infected MSM.

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.

Molecular analysis of transmission of hepatitis C virus in a nurse who acquired acute hepatitis C after caring for a viremic patient with epistaxis

A 23-year-old nurse (HC-IP) developed acute hepatitis C. Intrafamilial transmission of hepatitis C virus (HCV) was suspected initially because her parents were carriers of HCV of the same genotype (1b) as that of Patient HC-IP. However, the HCV isolate from Patient HC-IP and those from her parents shared identities of only 92.4-92.7% in the 1,087-nucleotide (nt) sequence within the NS5B region. It was then suspected that she contracted HCV infection during medical practice. Sixteen patients with antibodies to HCV (anti-HCV) were hospitalized 1-3 months before she became positive for anti-HCV. Upon analysis of stored serum samples, 14 of the 16 patients were found to be positive for HCV RNA, and 9 of the 14 viremic patients had genotype 1b HCV. Although the shared identities between the HCV isolate from Patient HC-IP and those from eight of the nine patients were merely 90.6-93.9% within the 1,087-nt NS5B sequence, the HCV isolate from the remaining one patient (HC-P12) was 99.7% identical to that from Patient HC-IP. Upon analysis of the E1 and E2 junctional region including hypervariable region 1 (283 nt), there was a close relationship (99.3-100%) between clones obtained from Patients HC-IP and HC-P12. Although the nurse HC-IP had a finger injury, she took care of Patient HC-P12, a 70-year-old man with HCV-related cirrhosis and recurrent epistaxis, occasionally without wearing protective gloves. This study indicates the occurrence of HCV transmission by exposure of nonintact skin to blood in health care settings.

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.

Factors associated with hepatitis C viremia in a large cohort of HIV-infected and -uninfected women

BACKGROUND

Co-infection with hepatitis C virus (HCV) is common among HIV-infected women.

OBJECTIVE

To further our understanding of the risk factors for HCV viremia and the predictors of HCV viral load among women.

STUDY DESIGN

We investigated sociodemographic, immunologic, and virologic factors associated with presence and level of HCV viremia among 1049 HCV-seropositive women, 882 of whom were HIV-infected and 167 HIV-uninfected at their entry into the Women's Interagency HIV Study.

RESULTS

Plasma HCV RNA was detected in 852 (81%) of these 1049 women (range: 1.2-7.8 log(10)copies/ml). HCV-viremic women were more likely to have an HIV RNA level >100,000 copies/ml (P=0.0004), to have reported smoking (P=0.01), or to be Black (P=0.005). They were less likely to have current or resolved hepatitis B infection. HCV RNA levels were higher in women who were >35 years old, or HIV-infected. Current smoking and history of drug use (crack/freebase cocaine, marijuana, amphetamines, or heroin) were each associated with both presence and level of viremia.

CONCLUSIONS

Substance abuse counseling aimed at eliminating ongoing use of illicit drugs and tobacco may reduce clinical progression, improve response to treatment, and decrease HCV transmission by lowering levels of HCV viremia in women.

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.

Complete genomes for hepatitis C virus subtypes 6f, 6i, 6j and 6m: viral genetic diversity among Thai blood donors and infected spouses

In this study, the first complete genome sequences for hepatitis C virus (HCV) subtypes 6f, 6i, 6j and 6m, obtained from infected blood donors in Chiang Mai, Thailand, are reported. Pairwise genome-wide nucleotide similarities between some of these isolates were higher than the 75-80% value used previously to define different HCV subtypes. To investigate further, the entire genomes of four prototype isolates, Th602 (6i), Th553 (6j), B4/92 (6m) and D86/93 (6n), were sequenced. Pairwise comparison of these sequences gave a similar range of nucleotide similarities, thereby providing new information for HCV subtype classification. In order to study the hypothesis of interspousal HCV transmission, four additional complete HCV genome sequences were obtained from two infected Thai blood donors and their spouses, C-0044 and C-0046 (6f), and C-0192 and C-0185 (6m). Pairwise comparison of the sequences revealed that C-0044 and C-0046 share a nucleotide similarity of 98.1%, whilst C-0185 and C-0192 have a similarity of 97.8%. Several other studies of partial HCV sequences of different genomic regions from HCV-infected couples have shown nucleotide similarities ranging from 96.3 to 100%. The similarities of the complete genome sequences from the two couples in the current study are consistent with HCV transmission between spouses.

Hepatitis C virus transmission and its risk factors within families of patients infected with hepatitis C virus in southern Iran: Khuzestan

AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV.

METHODS: In a case-control descriptive study we enrolled 300-household contacts of 60 index cases (40 males and 20 females) of HCV infection and 360 pair-matched controls in Ahwaz JundiShapour University Hospitals from August 1, 1998 to September 1, 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion Organization. Serum samples and demographic data and a medical history including the existence of risk factors for HCV (after a questionnaire on the risk factors for parenteral exposure) were obtained from each subject. Antibodies to HCV were detected employing a commercially available second-generation enzyme immunoassay (EIA, Abbott II). Positive serum specimens were retested using a second-generation recombinant immunoblot assay (RIBA-2) and a polymerase chain reaction for HCV RNA. Data analysis was carried out for intra-household clustering.

RESULTS: Only 4 of 300 (1.33%) cases of household contacts without percutaneous risk factors were positive for HCV Ab while the remaining 296 family contacts were negative for anti-HCV. The mean age of the index cases was 28.4 (Std 15.22) years. The anti-HCV prevalences in parents, spouses, children of the index cases were 0.87% (1/115), 3.39% (2/59)) and 0.79% (1/126), respectively. Among couple partners negative for anti-HCV antibodies, the mean duration of the sexual relationship was 6 years. The two-couple partners positive for anti-HCV antibodies married the index cases for longer than 15 years. The prevalence of positive HCV Ab among household contacts (1.33%) was not significantly higher than that in the controls (1%) (P > 0.06).

CONCLUSION: Intrafamilial transmission of HCV is not the significant transmission route and sexual transmission does not seem to play a role in the intrafamilial spread of HCV infection. Intrafamilial transmission of HCV is possible but occurs at a low rate.

[Development and role of comparative sequence analysis in medical virology]

INTRODUCTION

Development of the polymerase chain reaction and deoxyribonucleic acid sequencing techniques has enabled precise identification, classification and taxonomy of viruses. COMPARATIVE SEQUEENCE ANALYSIS: (Comparative sequence analysis methods can be used in medical virology for many practical purposes. They may be classified into three broad categories: I - reconstruction of genealogical relationships between individual viral isolatesfor detection and monitoring of sources, reservoirs and modes of viral transmission; II - virus genotyping, that is determination of relationships between genetic types of viruses and their phenotypic properties, which has important implications for immunoprophylaxis, therapy and prognosis of viral diseases, and III investigation of functional properties of defined viral sequences, of special importance for explanation of viral pathogenesis and design of antiviral drugs.

FUTURE PROSPECTS

The combination of DNA sequencing with polymerase chain reaction following reverse transcription with the use of random primers offers a universal means for diagnosis of viral infections.

Infectious Agents

There is substantial evidence that infectious agents play a causal role in a variety of human malignancies. These cancers include the liver, cervix, stomach, nasopharynx, bladder, and bile duct as well as Kaposi sarcoma (KS) and several lymphomas. This chapter summarizes the biological and epidemiologic features of each of the major oncogenic infections, beginning with the viruses, followed by H. pylori, and with a brief summary of the relevant parasites.

Sexual transmission of HCV between spouses

BACKGROUND AND AIMS

The sexual transmission of hepatitis C virus (HCV) is debated. By excluding other risk factors, the role of sexual intercourse in the transmission could be detected more accurately. We screened HCV prevalence and risk factors in the spouses of chronic hepatitis C (CHC) patients and followed the seroconversion rate of anti-HCV negative spouses.

PATIENTS AND METHODS

Six hundred spouses of CHC patients were recruited. The spouses' HCV risk factors were questioned and the spouses were tested for anti-HCV. The 216 spouses who were anti-HCV negative were checked annually for anti-HCV.

RESULTS

Anti-HCV was positive in 12 of 600 (2%) of the spouses. Of the 12 anti-HCV positive spouses, 11 were HCV-RNA positive. Of anti-HCV positive and negative spouse groups, mean age was 52.3 +/- 9.8 and 49.8 +/- 12.4 yr; duration of marriage was 1521 +/- 506.7 and 1532.4 +/- 670.2 wk (p > 0.05); and the number of total sexual intercourse was 434 +/- 295 and 307 +/- 333 (p= 0.055), respectively. In our prospective study, none of the spouses developed anti-HCV seroconversion in mean 35.7 +/- 6.3 months and 257.9 +/- 72.2 sexual intercourse.

CONCLUSIONS

Anti-HCV was found positive in 2% of the spouses. None of the seronegative spouses developed seroconversion in the 3-yr follow-up period. This is the first study that stresses the importance of the total number of sexual intercourse in sexual transmission (p= 0.055). Our results of special monogamous group with very limited risk factors support the role of number of total sexual intercourse in HCV transmission. However, the seroprevalence rate of the spouses was still within the upper limit of our country population.

Prevalence of hepatitis C infection in a population of asymptomatic people in a checkup unit in Mexico city

Hepatitis C virus (HCV) infection has an estimated prevalence of 3% around the world. Unfortunately, many persons with HCV infection are asymptomatic. The aim of this study was to determine the prevalence of hepatitis C Virus infection in asymptomatic persons. This study was carried out in a population-based cross-sectional study in the Checkup Unit of University Hospital in Mexico City. Patients with two or more HCV risk factors were studied. Serum specimens from all patients were screened for HCV RNA by qualitative polymerase chain reaction (PCR). HCV RNA-positive serum was also screened by quantitative PCR and for HCV genotype. Three hundred asymptomatic people were included, 194 men and 106 women, with a mean age of 46.8+/-11.9. Six (2%) of the 300 people were positive and viremic. The most common risk factors in positive patients were manicures or pedicures with a nonpersonal instrument and more than three sexual partners. We concluded that hepatitis C is frequent in asymptomatic people, and those people are often viremic. In addition, this study suggests that the spectrum of liver disease in asymptomatic and newly diagnosed HCV-positive persons is broad.

Lack of evidence of sexual transmission of hepatitis C virus in a prospective cohort study of men who have sex with men

OBJECTIVES

We studied the prevalence and incidence of hepatitis C virus (HCV) infection in the ongoing Omega Cohort Study of men who have sex with men (MSM).

METHODS

From January to September 2001, consenting men (n = 1085) attending a follow-up visit to the ongoing Omega Cohort Study were tested for HCV. If the test results were positive for HCV, we compared them with test results from previous serum samples collected from the time of entry into the original cohort study to determine the time of infection.

RESULTS

HCV prevalence at entry was 2.9% and was strongly associated with injection drug use (32.9% vs 0.3%, P<.0001). Only 1 seroconversion was identified in 2653 person-years of follow-up (incidence rate = 0.038 per 100 person-years). The seroconverter was an active injection drug user who reported needle sharing.

CONCLUSIONS

Sexual transmission of HCV among MSM appears to be rare.

Molecular epidemiology of the hepatitis C virus in Western Siberia

Western Siberia is the region with little information on the prevalence of hepatitis C virus (HCV) infection, genotypic diversity of HCV isolates and risk factors. A molecular epidemiological survey was conducted to clarify these issues. Four groups of volunteers were included in a cross-sectional study (n = 500 in each group): health care workers; daycare patients from a hospital for drug users, daycare patients from an AIDS prevention and control center; and persons admitted to a local general practice clinic for any reason (outpatients). The anti-HCV IgG prevalence was 4.6% in health care workers, 48.0% in a narcological center, 35.8% in AIDS center, and 5.6% in outpatients. HCV RNA was found in 79.3%-86.3% of seropositives. A total of 388 HCV isolates were genotyped by direct sequencing and phylogenetic analysis of the 5'-UTR and NS5B regions of HCV genome. The genotypes distribution was: 1b--50.3%, 2a--4.4%, 2c--0.3%, 3a--44.8%. One isolate (0.3%) could not be typed unambiguously. This genotypic diversity is intermediate between that of European Russia and China. Genotype 1 prevailed in an older age group (75% among 51-60 years old), and genotype 3 was most prevalent in young people (51.4% in 16-20 years old). A statistically significant (P < 0.05) increase in risk was found in intravenous drug users (odds ratio (OR) = 77.5), unemployed persons (OR = 16.3), persons having >4 sexual partners during lifetime (OR = 4.3), and male homosexuals (OR = 6.6).

Acute hepatitis C in HIV-infected men who have sex with men

BACKGROUND

Hepatitis C virus (HCV) is usually transmitted via the parenteral route, but there are widely discrepant findings on its possible sexual transmission. Thus there are no recommendations concerning protected sex for couples in which only one partner is HCV-infected. Whether HIV or other sexually transmitted diseases could favour HCV transmission remains unclear, but recent data suggesting an increasing incidence of acute HCV in HIV-infected men underline the major public health implications of this issue.

CASE REPORTS

Between June 2002 and July 2003, five HIV-infected homosexually active men presented with primary (n=4) and secondary (n=1) syphilis and concomitant abnormal liver function tests revealing acute asymptomatic HCV seroconversion. Other causes of acute viral hepatitis were inquired into and excluded. Highly at-risk sexual behaviour, including unprotected anal intercourse and unsafe oral sex, with concomitant syphilis, was found to be the only identifiable important risk factor for transmission of HCV.

CONCLUSIONS

Sexual transmission may be fuelling a significant increase in HCV seroconversions among HIV-infected men who have highly risky sexual behaviours. Given the recent data suggesting the spread of sexually transmitted infections among HIV-infected gay men, specific recommendations concerning safe sex are urgently needed.

Risk factors for hepatitis C infection among sexually transmitted disease-infected, inner city obstetric patients

Objective: To test the hypothesis that our inner city obstetric patients who have been infected with sexually transmitted diseases (STDs) will have a higher prevalence of hepatitis C virus infection than the general population and to identify specific risk factors and high-risk groups.

Methods: All patients in our prenatal clinic (July 1997–April 1999) who tested positive for one or more STDs were asked to return for hepatitis C antibody testing. Medical charts of all patients who returned for hepatitis C testing were reviewed.

Results: A total of 106 patients with STDs were tested for hepatitis C. Positive screening tests for anti-hepatitis C antibody were found in 6.6% (7/106) of the patients (95% CI = 2.7–13.1%). This frequency is significantly higher than the hepatitis C prevalence (1.8%) in the general United States population (p = 0.006). Multiple logistic regression analysis confirmed only older age (p = 0.016) and positive HIV status (p = 0.023) to be significant predictors of hepatitis C infection.

Conclusions: Inner city STD-infected obstetric patients are at high risk for hepatitis C infection compared with the general population. Increasing age and HIV-positive status are risk factors which are significantly associated with hepatitis C infection.

Hepatitis C Infection: A Clinical Review

Nearly three million persons in the United States are viremic with hepatitis C (HCV). Despite a decreasing incidence of HCV in this country, the prevalence of HCV-related chronic liver disease is increasing. Most infections in the United States are acquired by intravenous drug use. The chronicity rate of HCV is high, reaching 85% in some populations, and the risk of progression to advanced liver disease is as high as 20% within twenty years of infection. Host factors like alcohol use accelerate the rate of progression. The enzyme immunoassay is the preferred initial test for diagnosis; the third generation assay has greater than a 99% specificity in immunocompetent patients. Barring contraindications, the standard of care for treatment of chronic HCV has become pegylated interferon and ribavirin. With this therapy, the cure rate for treatment-naïve patients is about 55%, but rates are higher in certain groups. Common side effects of therapy include neuropsychiatric symptoms, influenza-like symptoms and hematological abnormalities.

Molecular investigation of interspousal transmission of hepatitis C virus in two Japanese patients who acquired acute hepatitis C after 40 or 42 years of marriage

A 65-year-old woman (C1I) and a 65-year-old man (C2I) contracted acute hepatitis C 40 or 42 years after marriage, respectively, in Japan. They had no discernible risk factors for acquiring hepatitis C virus (HCV) infection, except that they had monogamous sexual relationships with their spouses (C1S [66-year-old] with hepatocellular carcinoma and C2S [64-year-old] with liver cirrhosis, respectively) who were infected with HCV of the same genotype (1b) and had a high-titer HCV RNA in the serum (bDNA probe assay, 17 Meq/ml [C1S] and 15 Meq/ml [C2S]). The HCV isolates from Patients C1I and C1S and those from Patients C2I and C2S shared identity of 99.9% and 99.1%, respectively, in the 1,087-nucleotide (nt) sequence of the NS5B region, although these four isolates were only 91.7%-96.2% identical to the 94 reported genotype 1b isolates including those from Japanese patients. To confirm the high degree of genetic relatedness among ten HCV clones from each spouse within each pair of spouses, the E1 and E2 junctional region sequence (268 or 271 nt) including hypervariable region 1 (HVR-1) was analyzed. There was a close relationship between clones obtained from each spouse within each couple. Regarding the HVR-1 amino acid sequence, nine of the ten C1I clones were 100% identical with six of the ten C1S clones, and one each of the C2I and C2S clones differed by only one amino acid residue. This study indicates that two Japanese patients with acute hepatitis C had acquired HCV infection most probably by interspousal sexual transmission during a long-lasting marriage.

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.

Determining hepatitis C genotype by analyzing the sequence of the NS5b region

Assays to determine the hepatitis C virus (HCV) genotype have recently become useful for clinical decision making and may be suitable for epidemiological investigations, such as identifying HCV outbreaks in a given population. Molecular assays are the most common diagnostic tools for HCV genotyping. This study compares two genome typing assays, one, the Trugene 5'NC genotyping kit, uses the sequence of the 5' non-coding (5'NC) region and the other, a non-commercial assay, uses the non-structural 5b (NS5b) region. Serum samples from 203 chronically HCV-infected patients were tested. The 5'NC and the NS5b assays were both very effective in identifying the genotype (99 and 98.5%) and the results with the two methods were always concordant for the genotype. The NS5b analysis permitted the identification of the subtype in all samples, whereas the 5'NC region assay did not in 33% of samples. The NS5b analysis showed that one patient had a mixed infection with HCV subtypes 1a and 2c, while the 5'NC assay did not. It is concluded that phylogenetic analysis using both the 5'NC and the NS5b regions are reliable and convenient methods for HCV typing in clinical practice. But analysis of the NS5b region may be more useful for tracing the source of an HCV infection.

Sexual activity as a risk factor for hepatitis C

The accumulated evidence indicates that hepatitis C virus (HCV) can be transmitted by sexual contact but much less efficiently than other sexually transmitted viruses, including hepatitis B virus and human immunodeficiency virus (HIV). However, because sex is such a common behavior and the reservoir of HCV-infected individuals is sizable, sexual transmission of HCV likely contributes to the total burden of infection in the United States. Risk of HCV transmission by sexual contact differs by the type of sexual relationship. Persons in long-term monogamous partnerships are at lower risk of HCV acquisition (0% to 0.6% per year) than persons with multiple partners or those at risk for sexually transmitted diseases (0.4% to 1.8% per year). This difference may reflect differences in sexual risk behaviors or differences in rates of exposure to nonsexual sources of HCV, such as injection drug use or shared razors and toothbrushes. In seroprevalence studies in monogamous, heterosexual partners of HCV-infected, HIV-negative persons, the frequency of antibody-positive and genotype-concordant couples is 2.8% to 11% in Southeast Asia, 0% to 6.3% in Northern Europe, and 2.7% in the United States. Among individuals at risk for sexually transmitted diseases (STDs), the median seroprevalence of antibody to HCV (anti-HCV) is 4% (range, 1.6% to 25.5%). HIV coinfection appears to increase the rate of HCV transmission by sexual contact. Current recommendations about sexual practices are different for persons with chronic HCV infection who are in steady monogamous partnerships versus those with multiple partners or who are in short-term sexual relationships.

Sexual activity as a risk factor for hepatitis C

The accumulated evidence indicates that hepatitis C virus (HCV) can be transmitted by sexual contact but much less efficiently than other sexually transmitted viruses, including hepatitis B virus and human immunodeficiency virus (HIV). However, because sex is such a common behavior and the reservoir of HCV-infected individuals is sizable, sexual transmission of HCV likely contributes to the total burden of infection in the United States. Risk of HCV transmission by sexual contact differs by the type of sexual relationship. Persons in long-term monogamous partnerships are at lower risk of HCV acquisition (0% to 0.6% per year) than persons with multiple partners or those at risk for sexually transmitted diseases (0.4% to 1.8% per year). This difference may reflect differences in sexual risk behaviors or differences in rates of exposure to nonsexual sources of HCV, such as injection drug use or shared razors and toothbrushes. In seroprevalence studies in monogamous, heterosexual partners of HCV-infected, HIV-negative persons, the frequency of antibody-positive and genotype-concordant couples is 2.8% to 11% in Southeast Asia, 0% to 6.3% in Northern Europe, and 2.7% in the United States. Among individuals at risk for sexually transmitted diseases (STDs), the median seroprevalence of antibody to HCV (anti-HCV) is 4% (range, 1.6% to 25.5%). HIV coinfection appears to increase the rate of HCV transmission by sexual contact. Current recommendations about sexual practices are different for persons with chronic HCV infection who are in steady monogamous partnerships versus those with multiple partners or who are in short-term sexual relationships.

Does HIV infection favor the sexual transmission of hepatitis C?

BACKGROUND

There are widely discrepant findings on the sexual transmission of hepatitis C virus (HCV), commonly transmitted by the parenteral route. Coinfection with HCV is common in subjects infected with HIV.

GOAL

This case-control study evaluated the prevalence of anti-HCV in subjects with hetero- or homosexual contact and no history of intravenous drug abuse or blood transfusion, according to the presence or absence of HIV infection.

STUDY DESIGN

In this case-control study, the cases considered were 106 consecutive patients who showed positive anti-HIV test results. For each case, two control subjects were selected who had been screened for HIV infection at the authors' center and found to have anti-HIV-negative test results, and who matched the case in terms age (+/- 5 years), gender, and risk factor for parenterally transmitted infections.

RESULTS

The prevalence of subjects with positive test results for hepatitis B surface antigen (HBsAg) was similar between cases and control subjects (4.7% versus 2.4%). Positivity for anti-hepatitis B core antigen in connection with negative test results for HBsAg was observed more frequently in the 106 cases than in the 212 control subjects (33.9% versus 15.6%; P = 0.0003). Anti-HCV positivity was more frequent in the cases than in the control subjects (15.1% versus 5.2%; P = 0.005). In particular, among subjects who had hetero- or homosexual intercourse with a steady partner who had positive anti-HIV test results, anti-HCV positivity was observed in 18.7% of the 32 cases and 1.6% of the 64 control subjects (P = 0.008).

CONCLUSION

This study demonstrated that in subjects who had only a sexual risk factor for parenterally transmitted infections, HIV may enhance the sexual transmission of HCV.

Hepatitis C. Epidemiologic quandaries

Although many aspects of the transmission of HCV have been clarified, some important issues remain controversial, and the conventional wisdom may be based more on opinion than data (Table 2). HCV is transmitted by percutaneous exposure to contaminated blood, uncommonly from a mother to her infant and between sexual partners, and rarely during the provision of medical care in developed nations. Improved behavioral research instruments are needed to further the understanding of the practices that actually transmit infection. In addition, large, prospective studies are necessary to characterize the frequency [table: see text] of transmission between sexual partners and the potential role of cesarian section in reducing HCV transmission to infants.

Update on chronic viral hepatitis

Many recent and significant advances in the field of chronic viral hepatitis, including therapy, suggest that an update on chronic hepatitis is timely. Chronic hepatitis B virus infection remains a significant worldwide cause of liver cirrhosis and hepatocellular carcinoma, despite the wide availability of a long established and effective vaccine. Transmission occurs via perinatal, sexual, and parenteral routes (particularly intravenous drug abuse and although blood products still carry a risk, this is now extremely low in Western countries). Only a minority of infected adult cases develop chronic hepatitis but in children under 1 year, 90% develop chronic hepatitis. The clinical spectrum of chronic liver injury ranges from mild inflammation to end stage liver cirrhosis. Interferon alfa has been the mainstay of treatment for patients with active disease but nucleoside analogues (lamivudine and adefovir) are now available with similar efficacy. Patients with end stage liver disease and hepatocellular carcinoma can be offered transplantation but infection in the graft is commonplace. The combination of hepatitis B immunoglobulin and newer antiviral drugs reduce the incidence and severity of graft infection significantly. The hepatitis C virus epidemic of the latter half of the 20th century now affects more than 1% of populations worldwide. This RNA virus is spread parenterally and is becoming the leading indication for liver transplantation. The majority of patients develop chronic hepatitis, which may be progressive, evolving to significant liver disease (cirrhosis or hepatocellular carcinoma) in about 20% cases after decades. Treatment with the combination of interferon alfa and ribavirin is successful in up to 40% cases. Liver transplantation is a therapeutic option for some but graft infection is universal and often complicated by progressive liver fibrosis. A vaccine remains a remote prospect so that prevention is crucial. Hepatitis D virus infection occurs on a background of hepatitis B virus infection and can also cause liver damage. The response to antiviral therapy is poor. The newer "hepatitis" viruses G and TT do not cause significant liver injury.

Risk factors of hepatitis C virus-related liver cirrhosis in young adults: positive family history of liver disease and transporter associated with antigen processing 2(TAP2)*0201 Allele

The aim of this study was to clinically characterize young patients with hepatitis-C-related cirrhosis. We compared 27 patients with liver cirrhosis (Group LC) who were anti-HCV positive, aged 40 years or less at the time of diagnosis, with 323 consecutive patients with HCV-related chronic hepatitis (Group CH) matched for age and gender. Furthermore, Group LC was divided into two arbitrary groups (29-35 years, n = 8 /36-40 years, n = 19), based on the age of patients at the time of diagnosis of liver cirrhosis. Patients' characteristics and family history were investigated, and the frequency of transporter associated with antigen processing 2 (TAP2) was determined. A family history of liver disease was present in 40.7% of Group LC but in 18.0% of Group CH (P < 0.05). The younger the age of diagnosis of cirrhosis in Group LC, the higher the frequency of a positive family history (29-35 years, 87.5%; 36-40 years, 21.1%, P < 0.05). The frequency of TAP2*0201 was significantly higher in young adult patients with HCV-related liver cirrhosis than in HCV carriers with normal ALT (P < 0.05), and tended to be higher than in uninfected normal subjects (P = 0.05). The cumulative survival rate of cirrhosis patients with family history of liver diseases was significantly lower than that of cirrhosis patients without such history (P < 0.05). Our findings suggest that a positive family history of liver disease and TAP2*0201 polymorphism may be risk factors for HCV-related liver cirrhosis in young adults.

Acute self-limiting hepatitis C after possible sexual exposure: sequence analysis of the E-2 region of the infected patient and sexual partner

We describe a case of symptomatic acute infection with HCV in a woman whose sexual partner had chronic hepatitis C. The patient cleared HCV RNA 8 weeks after the onset of acute hepatitis and was found to be persistently HCV-RNA negative during 90 weeks of follow-up. Part of the E-2 region of HCV was directly sequenced in the patient and her sexual partner. Four local controls with subtype-1a infection and 9 1a isolates obtained from GenBank were analyzed. The average nucleotide divergence between the sequences of the infected patient and her sexual partner was 5.1%, compared with an average nucleotide divergence of 19.4% (range 16.6-21.8%) between the sequences of the patient and those of controls. Comparison of the phylogenetic trees in the partial E-2 region showed that the sequence of the patient was closely related to that of her sexual partner. Our findings suggest that the infection was transmitted to the patient from her sexual partner. The resolution of acute hepatitis C in this case was probably related to the host rather than to intrinsic characteristics of the HCV genome.

Sexual transmission of hepatitis C virus

In order to contribute to a better understanding of the forms of acquisition of hepatitis C virus (HCV) in Brazil, with special emphasis on sexual transmission, we determined the presence of HCV infection in regular partners and in non-sexual home communicants of blood donors seen at Fundação Pró-Sangue Hemocentro de São Paulo from January 1992 to July 1996. Of 154 blood donors with HCV infection (index cases), 111 had had regular partners for at least 6 months. Sixty-eight of 111 partners were evaluated for HCV infection. Of these, 8 (11.76%) were considered to have current or previous HCV infection; a history of sexually transmissible diseases and index cases with a positive HCV-RNA test were more prevalent among partners with HCV infection. Of the 68 index cases whose partners were studied, 56 had non-sexual home communicants. Of the total of 81 home communicants, 66 accepted to be evaluated for HCV infection. None of them was HCV-positive, suggesting that the high prevalence of HCV infection among partners may be attributed at least partially to sexual transmission.

Molecular evidence of male-to-female sexual transmission of hepatitis C virus after vaginal and anal intercourse

Hepatitis C virus (HCV) was transmitted from a chronic carrier to his female partner during unprotected anal and vaginal intercourse. Based on HVR1 and phylogenetic tree analysis, the couple had closely related isolates. These findings confirm sexual transmission of HCV without other risk factors.

Clinical significance of hepatitis C virus genotypes

On the basis of phylogenetic analysis of nucleotide sequences, multiple genotypes and subtypes of hepatitis C virus (HCV) have been identified. Characterization of these genetic groups is likely to facilitate and contribute to the development of an effective vaccine against infection with HCV. Differences among HCV genotypes in geographic distributions have provided investigators with an epidemiologic marker that can be used to trace the source of HCV infection in a given population. HCV genotype 1 may represent a more aggressive strain and one that is less likely to respond to interferon treatment than HCV genotype 2 or 3. However, these observations require confirmation before HCV genotyping can be used in clinical settings.

Clinical significance of hepatitis C virus genotypes

On the basis of phylogenetic analysis of nucleotide sequences, multiple genotypes and subtypes of hepatitis C virus (HCV) have been identified. Characterization of these genetic groups is likely to facilitate and contribute to the development of an effective vaccine against infection with HCV. Differences among HCV genotypes in geographic distributions have provided investigators with an epidemiologic marker that can be used to trace the source of HCV infection in a given population. HCV genotype 1 may represent a more aggressive strain and one that is less likely to respond to interferon treatment than HCV genotype 2 or 3. However, these observations require confirmation before HCV genotyping can be used in clinical settings.

Intrafamilial transmission of hepatitis C virus: a systematic review

To examine the risk of hepatitis C virus (HCV) transmission between patients infected with HCV and their household members (siblings, offspring and parents), as well as their stable heterosexual partners, a systematic search of the MEDLINE database was undertaken for all relevant articles published up to June 1997. English language publications or those supplemented with an English abstract that reported studies concerning hepatitis C, and household, intrafamilial, sexual and intraspousal transmission of HCV, were reviewed. Data from uncontrolled and controlled studies were collected and analysed separately. Studies reporting the exclusive use of first-generation anti-HCV antibodies without supplemental tests were excluded. Pre- or postnatal mother-to-child transmission of HCV and homosexual and heterosexual transmission of HCV among non-permanent couples were not included. Unweighted data from individual studies were pooled for each category of family member. Data were also analysed separately for Japanese and non-Japanese studies because there is evidence that intrafamilial transmission may differ, based on endemicity of the viral infection. Comparisons were drawn only from controlled studies that reported the prevalence of HCV in family members of both HCV-positive and HCV-negative controls. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated for each family category. In uncontrolled studies, the pooled prevalence of anti-HCV among 4250 stable sexual contacts of patients with HCV-related chronic liver disease (CLD) was 13.48%, while the pooled prevalence of anti-HCV among 580 stable sexual contacts of patients who contracted HCV as a result of multiple transfusions was 2.41%. In controlled studies, the pooled prevalence of anti-HCV among 175 siblings and household contacts of patients with CLD was 4.0% compared with 0% among 109 contacts of anti-HCV-negative controls (OR 9.75, 95% CI 0.91 ad infinitum). The pooled prevalence of anti-HCV among offspring of Japanese HCV-infected CLD patients was 17% compared with 10.4% among offspring of HCV-negative Japanese controls (OR 1.77, 95% CI 1.21-2. 58, P=0.002). The pooled prevalence of anti-HCV among spouses of non-Japanese HCV-infected CLD patients was 15.2% compared with 0.9% in the spouses of non-Japanese HCV-negative controls (OR 20.57, 95% CI 6.05-84.08, P=0.0001). The prevalence of anti-HCV among non-Japanese offspring and Japanese spouses of HCV-infected patients was not increased compared with controls. HCV genotype homology and mutant analysis studies in pairs of HCV-infected patients and their HCV-infected contacts showed that concordant genotype homology was found in 66% of non-sexual contacts and in 74% of sexual contacts. Sequence homology of greater than 92% was found in 19 out of 35 pairs. Hence, evidence exists that familial, non-sexual and sexual transmission of HCV does occur. In Japanese patients, transmission probably occurs in younger family members while, in non-Japanese patients, transmission probably occurs at an older age, after contact with an HCV-infected spouse.

Sexual transmission of hepatitis C virus

Sexual transmission of hepatitis C virus (HCV) occurs; however, to what extent is still unclear. In this presentation relevant data from the literature concerning the following key issues will be presented: presence of HCV in the seminal fluid and vaginal secretions; presence of HCV infection in sexually promiscuous individuals; presence of HCV infection among sexual partners to HCV-infected individuals; and molecular biology evidence of sexual transmission. An anti-HCV prevalence of 2-12% is seen in sexually promiscuous individuals, which is higher than that usually seen among blood donors. In case-control studies, HCV infection is associated with sexual promiscuity and sex with a partner who has a past history of hepatitis. In most studies, HCV infection is common among sexual partners of HCV-infected subjects. Genotyping and genome sequencing provide further evidence for intraspousal transmission of HCV Despite these findings, stable sexual partners of hemophiliacs or recipients of HCV-contaminated immunoglobulin preparations rarely become infected. These discrepancies are not fully understood. Other sexual behaviours or confounding non-sexual transmission routes could play a part.

Hepatitis C epidemiology

Hepatitis C virus infection occurs in all parts of the world. Infection is generally due to percutaneous exposures, though sexual and perinatal transmission may occur. While further study is needed to elucidate the biology of HCV transmission and develop vaccines for prevention, new HCV infections can be reduced by economic development and education regarding blood-borne infections.

Heterosexual transmission of GB virus C/hepatitis G virus infection to non-intravenous drug-using female prostitutes in Fukuoka, Japan

To determine if GB virus C (GBV-C) or hepatitis G (HGV) infection can be transmitted by heterosexual intercourse, we tested serum samples from 234 non-drug-injecting female prostitutes for GBV-C/HGV. We used reverse transcription polymerase chain reaction to test for GBV-C/HGV RNA and ELISA for GBV-C/HGV-E2 antibody. The prevalence of total GBV-C/HGV marker (GBV-C/HGV RNA and/or GBV-C/HGV-E2 antibody) was 58/234 (24.8%) in the prostitutes, and 7/71 (8.9%) in matched controls. The GBV-C/HGV RNA and GBV-C/HGV-E2 antibody concurrence rate was 12.5% for the prostitutes, but was nil in matched controls. Total GBV-C/HGV marker was significantly higher in the prostitutes than in matched controls. Additionally, total GBV-C/HGV marker was associated with the number of years engaged in prostitution after adjusting for age. We found hepatitis B virus and hepatitis C virus infections in prostitutes to be associated with syphilis infection, but GBV-C/HGV infection was not. Thus, it seems likely that GBV-C/HGV can be transmitted by heterosexual intercourse, even in the absence of syphilis.

Lack of evidence for the heterosexual transmission of hepatitis C

The importance of sexual transmission in the epidemiology of hepatitis C virus (HCV) infection is still controversial. To assess the risk of heterosexual HCV transmission, we examined eighty patients with chronic HCV-associated liver disease and their spouses in a cross-sectional clinical and serological cohort study. Serum samples from index patients and their spouses were assayed for HCV antibodies and HCV RNA. In the couples positive for both, further HCV genotyping was done. A questionnaire addressing points such as additional risk factors for HCV infection, sexual behaviour or duration of partnership was completed by all couples. HCV antibodies were detected in four (5%) spouses, of whom three (4%) were also positive for HCV-RNA. HCV genotyping revealed concordance (genotype 1) in two couples, indicating a risk of interspousal HCV transmission of 2.5%. Spouses of patients with HCV viraemia and chronic liver disease have a low risk for acquiring HCV. Even long-term spouses seem not to be at increased risk. We therefore suggest that the risk of HCV transmission between monogamous sex partners does not depend on the duration of sexual exposure.

Inquiries on intraspousal transmission of hepatitis C virus: benefits and limitations of genome sequencing and phylogenetic analysis

During recent years, courts had to decide in some notable cases whether or not defendants infected the plaintiffs with HIV. Lawsuits on the transmission of other viral pathogens up to now have hardly become known. We report here on the use of genome sequencing and phylogenetic analysis to investigate possible intraspousal transmission of hepatitis C virus (HCV). The high degree of genetic relatedness observed in phylogenetic analysis among the HCV strains isolated from the couple demonstrates that the man and the woman are infected with the same isolate of the virus. After other plausible routes of infection have been virtually excluded by anamnestic and conventional epidemiological evaluation we could infer that the man most probably has infected his girlfriend with HCV. This conclusion was further supported by the finding that both are also infected with closely related isolates of GB virus C (GBV-C). Thus, the results from molecular biological investigations and epidemiological evaluation are complementary pieces of evidence in inquiries on possible intraspousal transmission of HCV.

Sexual transmission of hepatitis C virus and prevention with intramuscular immunoglobulin

The sexual transmission of hepatitis C virus (HCV) has long been debated. The prevalence of infected at-risk partners varies from 0% to 30%. In a prospective study, the risk of infection was quantified in steady heterosexual partners and the prophylactic effect of normal human polyvalent immune serum globulin (ISG) was evaluated. A total of 899 at-risk partners of HCV-infected patients were enrolled in a single-blind randomized controlled trial and assigned to receive every 2 month 4 mL of intramuscular ISG from unscreened donors (450 partners) or placebo (499 partners). Seven partners developed acute HCV infection (increased aminotransferase levels and appearance of HCV-RNA): six of the placebo group (incidence density [ID] 12.00/1,000 person year; 95% confidence interval [CI] 3.0 to 21.61), and only one of the ISG-treated group (ID 1.98/1,000 person year; 95% CI 0 to 5.86). The risk of infection was significantly higher in controls versus treated individuals (p = 0.03). Six couples had genotype 1b (85%), and one couple had genotype 1a; HCV sequence homology strongly supported sexual transmission. Our trial demonstrates that HCV infection can be sexually transmitted and quantifies the risk of sexual transmission: for every year of at-risk sexual relationship, almost 1% of the partners became infected. Intramuscular ISG is safe and well tolerated. Unlike ISG from screened donors, ISG from donors unscreened for anti-HCV contains high titers of anti-gpE1/gpE2 neutralizing antibodies and high neutralizing activity. Anti-HCV hyperimmune globulin could be prepared from anti-HCV-positive blood units and could be used to protect sexual partners and in other at-risk situations of exposure to HCV infection.