Low risk of sexual transmission of hepatitis C virus

The clinical management of HCV in the HIV-infected patient

Chronic hepatitis C affects an estimated 170 million persons worldwide and due to shared transmission routes many persons are coinfected with HIV. Since the advent of HAART, HIV patients have longer life expectancy and suffer fewer AIDS-related complications. The result has been an increase in morbidity and mortality from HIV-associated non-AIDS conditions, with high rates of liver-related deaths resulting from HCV in the coinfected population. Coinfection with HIV is an independent predictor of liver disease progression, and proper staging of fibrosis is of critical importance in the coinfected patient. In contrast to HIV, it is possible to eradicate HCV infection; and undetectable viral load 12 weeks after cessation of therapy, or sustained viral response (SVR), is considered a clinical cure. As achievement of SVR has been associated with significantly reduced mortality from liver disease and liver disease complications, it is imperative that patients coinfected with HIV-HCV receive therapy for their HCV infection. The length of therapy with previously available interferon-based regimens added a significant burden to HIV-HCV-coinfected patients. Newer, all-oral, interferon-free regimens promise to simplify treatment regimens, reduce side-effect profiles, and demonstrate reduced drug interactions with numerous HAART regimens.

Multicenter evaluation of a fully automated third-generation anti-HCV antibody screening test with excellent sensitivity and specificity

Early detection of hepatitis C virus (HCV) is an important step in preventing progression to cirrhosis and hepatocellular carcinoma. Serologic assays for anti-hepatitis C (anti-HCV) antibody are valuable first-line tests in the screening and diagnosis of HCV infection. The aim of this multicenter study was to compare the Elecsys(®) Anti-HCV assay with alternative CE-marked Anti-HCV antibody assays against a range of samples that included 1,138 blood donors, 3,553 unselected routine daily specimens, and 46 pre-selected seroconversion panels. Specificity of the Elecsys Anti-HCV assay was 99.5% with blood donor samples and 99.4% with routine clinical specimens. These were similar to those obtained with the Prism(®) Anti-HCV, Architect(®) Anti-HCV assay, ADVIA(®) Centaur Anti-HCV assay and Vitros(®) Eci aHCV assays. Seroconversion sensitivity for the Elecsys Anti-HCV assay was similar to that of the Architect Anti-HCV, AxSYM HCV version 3.0, ADVIA Centaur Anti-HCV, and Vitros Eci aHCV assays. In fact, seroconversion testing on 46 commercially available panels showed that the difference in first detecting a positive blood sample was less than one day between assays (not statistically significant). The Elecsys Anti-HCV assay as well as the Architect, Prism, and Vitros Anti-HCV immunoassays revealed a seroconversion sensitivity of 100%, whereas the ADVIA Centaur HCV immunoassay showed a sensitivity of only 97.5% (39/40). Overall, the performance of the Elecsys Anti-HCV assay was similar to the performances of the comparator CE-marked Anti-HCV antibody assays.

Désir d'enfant et infections virales: hépatites C et B et virus de l'immunodéficience humaine

The French law (arrêté du 10 mai 2001) allows Assisted Reproductive Techniques (ART) in case of infection with human immunodeficiency virus, hepatitis C virus or hepatitis B virus. Our six years' experience is positive even if pluridisciplinary care needs specific equipment and human forces. Couples express high motivation. The wish to become a parent leads to a better care of the infection. ART results are excellent in case of male contamination, not as good when the female partner is infected but still encouraging. No contamination of the partner or the offspring occurred after ART. Data are already collected in France in this context. A European register should be constituted in an early future.

Evaluating replication-defective vesicular stomatitis virus as a vaccine vehicle

We have generated replication-competent (VSV-C/E1/E2) and nonpropagating (VSVDeltaG-C/E1/E2) vesicular stomatitis virus (VSV) contiguously expressing the structural proteins of hepatitis C virus (HCV; core [C] and glycoproteins E1 and E2) and report on their immunogenicity in murine models. VSV-C/E1/E2 and VSVDeltaG-C/E1/E2 expressed high levels of HCV C, E1, and E2, which were authentically posttranslationally processed. Both VSV-expressed HCV E1-E2 glycoproteins were found to form noncovalently linked heterodimers and appeared to be correctly folded, as confirmed by coimmunoprecipitation analysis using conformationally sensitive anti-HCV-E2 monoclonal antibodies (MAbs). Intravenous or intraperitoneal immunization of BALB/c mice with VSV-C/E1/E2 or VSVDeltaG-C/E1/E2 resulted in significant and surprisingly comparable HCV core or E2 antibody responses compared to those of control mice. In addition, both virus types generated HCV C-, E1-, or E2-specific gamma interferon (IFN-gamma)-producing CD8(+) T cells, as determined by enzyme-linked immunospot (ELISPOT) analysis. Mice immunized with VSVDeltaG-C/E1/E2 were also protected against the formation of tumors expressing HCV E2 (CT26-hghE2t) and exhibited CT26-hghE2t-specific IFN-gamma-producing and E2-specific CD8(+) T-cell activity. Finally, recombinant vaccinia virus (vvHCV.S) expressing the HCV structural proteins replicated at significantly lower levels when inoculated into mice immunized with VSV-C/E1/E2 or VSVDeltaG-C/E1/E2, but not with control viruses. Our data therefore illustrate that potentially safer replication-defective VSV can be successfully engineered to express high levels of antigenically authentic HCV glycoproteins. In addition, this strategy may therefore serve in effective vaccine and immunotherapy-based approaches to the treatment of HCV-related disease.

HIV, HBV, and HCV infections among drug-involved, inner-city, street sex workers in Miami, Florida

This study describes the rates of HIV, HBV, and HCV seropositivity among drug-involved, female street sex workers in low-income, inner-city sections of Miami, Florida; further, their sociodemographic characteristics, drug use, and sexual risk behaviors were assessed; and predictors of infection were reported. A sample of 586 sex workers was recruited through targeted sampling methods, interviewed, and counseled and tested for the presence of antibody to HIV, HBV, and HCV. Respondents' median age was 38 years, median time in sex work was 14 years, all were heavily involved in the use of alcohol and drugs, and 42% were homeless. More than half (51.0%) had engaged in unprotected vaginal sex in the past month. Prevalences were HIV, 22.4%; HBV, 53.4%; HCV, 29.7%. A multidimensional public health program must address not only issues related to unsafe sex, but also the problems of drug abuse, homelessness, and other lifestyle factors that contribute to risk behaviors.

Performance characteristics of the ARCHITECT anti-HCV assay

INTRODUCTION

The ARCHITECT Anti-HCV assay is a fully automated high throughput chemiluminescent microparticle immunoassay (CMIA) for the detection of antibodies to structural and nonstructural proteins of the hepatitis C virus (HCV). To further enhance the performance of this test, the assay was modified to improve the specificity for blood donor specimens.

METHODS

The specificity of the enhanced ARCHITECT Anti-HCV assay was evaluated by screening blood donor samples randomly collected from various German blood banks, as well as hospitalized patient samples derived from Germany and the US. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels and on a commercially available worldwide anti-HCV genotype performance panel.

RESULTS

Apparent specificity of the modified ARCHITECT Anti-HCV assay in a blood donor population consisting of 3811 specimens was 99.92%, compared to 99.76% for the current on-market assay. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels. Seroconversion sensitivity equivalent to or better than the current on-market product was observed by testing 33 seroconversion panels.

CONCLUSION

This study demonstrates that the modified version of the ARCHITECT Anti-HCV assay shows improved specificity for blood donor specimens compared to the current assay on market without compromising sensitivity. With the availability of the improved ARCHITECT Anti-HCV assay and the recent launch of the ARCHITECT HIV Ag/Ab Combo assay, the ARCHITECT system now offers a full hepatitis/retrovirus menu with excellent performance on a high throughput, random access, automated analyzer, ideally suited for blood screening and diagnostic applications.

Presence of hepatitis C virus (HCV) RNA in the genital tracts of HCV/HIV-1-coinfected women

BACKGROUND

Hepatitis C virus (HCV)-infected women--in particular, those coinfected with human immunodeficiency virus type 1 (HIV-1)--can transmit infection to their children and sex partners.

METHODS

The present study was conducted to analyze the presence of HCV RNA in cervicovaginal lavage (CVL) fluid from 71 women (58 HCV/HIV-1-coinfected women and 13 HCV-infected, HIV-1-uninfected women) enrolled in the Women's Interagency HIV Study.

RESULTS

HCV RNA was detected (by a commercial polymerase chain reaction assay) in CVL fluid from 18 (29%) of the HIV-1-infected women and from none of the HIV-1-uninfected women (P<.05). Multivariate analysis revealed that risk factors for the presence of HCV RNA in CVL fluid were HCV viremia (odds ratio [OR], 16.81; P=.02) and HIV-1 RNA in CVL fluid (OR, 19.87; P=.02). This observation suggests local interactions between HIV-1 and HCV in the genital tract compartment. There was no correlation between HCV RNA in CVL fluid and CD4, CD8, or CD3 cell counts, HIV-1 RNA viremia, the number of leukocytes in CVL fluid, or HIV-1 therapy. Furthermore, in 3 of 5 analyzed patients who had a detectable CVL HCV RNA load, we found viral variants differing in the 5' untranslated region that were present neither in plasma nor in peripheral-blood mononuclear cells.

CONCLUSIONS

Our observations point to the importance of the genital tract compartment, in which local HCV replication could be facilitated by local HIV-1 replication.

Hepatitis C virus infection among prisoners in the California state correctional system

BACKGROUND

Incarcerated populations are at high risk for hepatitis C virus (HCV) infection, yet prisoners are not routinely screened or treated for HCV infection. Understanding the risk factors of HCV infection among prisoners could help improve HCV interventions.

METHODS

Prevalence and risk of HCV infection among 469 prisoners entering California State correctional facilities were assessed using HCV antibody screening, HCV RNA measurement, and structured interviews. Multivariate logistic regression analysis was used to identify independent correlates of HCV infection.

RESULTS

The prevalence of HCV infection was 34.3% overall (95% confidence interval [CI], 30%-38%) and was 65.7% among those with a history of injection drug use (IDU), compared with 10.2% among those with no history of IDU (odds ratio [OR], 17.24; 95% CI, 10.52-28.25). Significant differences in HCV antibody positivity were found in association with age at first detention but not with the nature of the crime. Independent correlates of HCV infection included age, history of IDU, cumulative time of incarceration, biological sex (OR for females subjects compared with males subjects, 0.35; 95% CI, 0.13-0.96), and a history of having sex with a male IDU (OR, 4.42; 95% CI, 1.46-13.37). We identified significant differences in risk factors between male and female subjects--notably, that the risk of HCV infection was significantly elevated among female non-IDUs who reported having sexual partners with a history of IDU. Among non-IDUs, correlates of HCV infection included history of receipt of blood products and cumulative years of incarceration.

CONCLUSIONS

HCV infection is pervasive among the California prison population, including prisoners who are non-IDUs and women with high-risk sexual behavior. These results should promote consideration of routine HCV antibody screening and behavioral interventions among incarcerated men and women.

Lack of evidence of sexual transmission of hepatitis C among monogamous couples: results of a 10-year prospective follow-up study

The risk of sexual transmission of hepatitis C virus (HCV) infection was evaluated among 895 monogamous heterosexual partners of HCV chronically infected individuals in a long-term prospective study, which provided a follow-up period of 8,060 person-years. Seven hundred and seventy-six (86.7%) spouses were followed for 10 yr, corresponding to 7,760 person-years of observation. One hundred and nineteen (13.3%) spouses (69 whose infected partners cleared the virus following treatment and 50 who ended their relationship or were lost at follow-up) contributed an additional 300 person-years. All couples denied practicing anal intercourse or sex during menstruation, as well as condom use. The average weekly rate of sexual intercourse was 1.8. Three HCV infections were observed during follow-up corresponding to an incidence rate of 0.37 per 1,000 person-years. However, the infecting HCV genotype in one spouse (2a) was different from that of the partner (1b), clearly excluding sexual transmission. The remaining two couples had concordant genotypes, but sequence analysis of the NS5b region of the HCV genome, coupled with phylogenetic analysis showed that the corresponding partners carried different viral isolates, again excluding the possibility of intraspousal transmission of HCV. Our data indicate that the risk of sexual transmission of HCV within heterosexual monogamous couples is extremely low or even null. No general recommendations for condom use seem required for individuals in monogamous partnerships with HCV-infected partners.

A national survey of genitourinary medicine clinic attenders provides little evidence of sexual transmission of hepatitis C virus infection

OBJECTIVE

To determine the prevalence and genetic diversity of hepatitis C virus in genitourinary medicine clinic attenders and to assess the extent of sexual transmission of the virus.

METHODS

A cross sectional, unlinked, anonymous survey in 14 genitourinary medicine clinics situated in England, Wales, and Northern Ireland. Serum specimens from genitourinary medicine clinic attenders, retained as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP) serum archive, were tested in small pools, for the presence of antibody to hepatitis C virus (anti-HCV). The main outcome measures were prevalence of antibodies to hepatitis C virus and identification of hepatitis C virus genotypes.

RESULTS

Testing of 17,586 specimens from 1995 showed an adjusted prevalence of anti-HCV in genitourinary medicine clinic attenders of 1.03% (95% CI: 0.89 to 1.16) overall and 0.65% (95% CI: 0.51 to 0.78) among those who did not report injecting drug use. Prevalence in injecting drug users attending genitourinary medicine clinics was 36.9% in both 1995 and 1996. Heterosexual injecting drug users had a higher prevalence of anti-HCV than homosexual/bisexual injectors. The most common hepatitis C genotypes were types 3a and 1a. There was a high degree of concordance between genotype and serotype.

CONCLUSIONS

The low prevalence of anti-HCV in genitourinary medicine clinic attenders who deny injecting drugs suggests that the majority of hepatitis C infections have been acquired in adult life, mostly by injecting drug use, and that the hepatitis C virus is rarely transmitted sexually. The use of needle exchanges may explain the relatively low prevalence observed in the injecting drug users.

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.

Current and future hepatitis C virus diagnostic testing: problems and advancements

Serological antibody assays used in hepatitis C virus diagnosis have improved in sensitivity and specificity. However, detection of active viremia or monitoring levels of virus during or after patient treatment is most commonly undertaken using nucleic acid-based technologies. Advancements in diagnostic technologies and implications for managing patients with hepatitis C in various clinical settings are discussed.

Reproductive choices for couples with haemophilia

: Summary. The impact of having a child with an inherited bleeding disorder such as haemophilia can have a far-reaching effect on the individual as well as other close family members. This situation is further complicated in the case of human immunodeficiency (HIV) serodiscordant couples, where the haemophilic man is affected with HIV through infected blood products whilst his partner is seronegative and wanting to have children. It is essential that information on the effects of haemophilia, its inheritance, the possibilities of antenatal diagnosis, the consideration of selective abortion and the new reproductive opportunities available to these couples are made accessible so that an informed decision about proceeding with having a family can be made. Couples may wish to have a family through nonreproductive methods such as fostering or adoption. Alternatively, they may wish to remain childless. In this paper, the terms 'having children' and 'having a family' will refer to conception through biological reproduction. Pre-implantation genetic diagnosis (PGD) offers families at risk of having a child with certain inherited genetic disorders the opportunity to give birth to an unaffected child. It may be considered as an option for couples who would not wish to have prenatal diagnosis leading to possible termination of a pregnancy. Assisted conception techniques, such as 'sperm washing' or the use of 'donor sperm', offer serodiscordant couples affected by HIV a risk-reduced or risk-free opportunity, respectively, to have a child without infecting the mother, who could in turn infect the fetus by vertical transmission. This article, in addition to outlining the inheritance of haemophilia and the more common prenatal screening and diagnostic tests, discusses in more detail the latest reproductive opportunities available for families affected by haemophilia and considering having a family.

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 virus infection in spouses: sexual transmission or common exposure to the same risk factors?

OBJECTIVES

The aim of this study was to evaluate whether the transmission of hepatitis C virus (HCV) between spouses occurs through sexual contact or through other types of exposure.

METHODS

We consecutively enrolled 311 chronic HCV carriers and their spouses. The spouses underwent HCV blood testing. Exposure to parenteral risk factors was compared between couples of which both partners were HCV positive and couples with one positive partner. In couples with both partners positive, qualitative detection of serum HCV RNA and genotyping were performed.

RESULTS

The prevalence among spouses was 10.3% (32/311). The mean age was higher for HCV-positive spouses (57.7 vs 49.6 yr for HCV-negative spouses; p < 0.01). The prevalence among spouses increased with the duration of marriage, whereas no difference was found in relation to the clinical status of the index case. The 32 HCV-positive spouses reported parenteral exposure (blood transfusion, drug use, and use of multiple-use glass syringes inside or outside the family) more often than the 279 HCV-negative spouses (84.4% vs 26.2%; odds ratio [OR], adjusted for age by multiple logistic regression analysis, 12.4; 95% CI = 4.5-34.0). The percentage of couples sharing glass syringes was significantly higher among those with both partners infected (65.6% vs 12.9%; OR = 12.9; 95% CI = 5.4-31.4). Qualitative serum HCV RNA was determined in 22 couples with both partners infected; in 13 of them, both partners were HCV RNA positive, whereas in the remaining nine, only one partner was positive. In eight of the 13 couples with both partners HCV RNA positive, the same genotype was found for both partners.

CONCLUSIONS

The findings that the same genotype was detected for both partners in relatively few couples, and that a history of parenteral exposure was an independent predictor of HCV positivity, suggest that the risk of sexual transmission is low. The sharing of glass syringes may have played an important role in transmission between spouses.

Issues in HIV/Hepatitis C Co-infection

Co-infection of patients with hepatitis C virus (HCV) and HIV is prevalent. HCV disease is clearly exacerbated in the setting of HIV disease, and the long-term effects of HCV have become an increasing concern as patients live longer on highly active antiretroviral therapy. Although treatment for HCV disease is evolving rapidly, its role in the HIV-infected patient is not well delineated. This review will focus on the major issues in the HIV/HCV co-infected patient and discuss therapy for HCV in the era of highly active antiretroviral therapy.

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.

The prevalence of hepatitis B and C in HIV-positive Greek patients: relationship to survival of deceased AIDS patients

OBJECTIVES

To determine the prevalence of hepatitis viruses B (HBV) and C (HCV) co-infections in HIV-infected patients and the overall impact of these co-infections on deceased AIDS patients survival.

METHODS

One hundred and eighty-one patients (159 males, 22 females) infected with HIV, attending an academic AIDS unit in Athens, Greece, constituted the study population. The study population consisted of 124 homo/bisexual men, 34 heterosexuals, 12 intravenous drug users (IDU) and 11 blood transfusion recipients. Virological markers tested for HBV infection included HBsAg, anti-HBs and total anti-HBc by enzyme-linked immunoassays. Detection of HCV antibodies was carried out by third generation enzyme-linked immunoassay, and repeatedly positive samples were further tested by a supplemental enzyme-linked immunoassay; only sera reactive by both methods were considered to be HCV-positive.

RESULTS

The prevalence of HBV markers was 67.4%: 71.8% in homo/bisexuals, 35.3% in heterosexuals, 91.7% in IDUs and 90.9% in blood transfusion recipients (P = 0.00004). The prevalence of HCV antibodies was 13.8%: 8.1% in homo/bisexuals, 8.8% in heterosexuals, 58.3% in IDU and 45.5% in blood transfusion recipients (P<0.000001). The prevalence of HCV antibodies was not significantly higher in homo/bisexuals than in heterosexuals (P= 0.8). Coinfection with HBV or HCV, or both, did not influence the survival of deceased AIDS patients (n = 73).

CONCLUSIONS

HBV infection was equally prevalent among homo/bisexuals and IDU with HIV infection, whereas HCV infection was more prevalent in IDU than in homo/bisexuals with HIV infection. The prevalence of HCV infection was equal among heterosexuals and homo/bisexuals, indicating that if sexual transmission of HCV occurs, homo/bisexuals are not at greater risk than heterosexuals. Finally, the survival of deceased AIDS patients was not affected by the presence of HBV and HCV co-infections.

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.

Sexual transmission of hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) is the cause of almost all cases of parenterally transmitted non-A, non-B viral hepatitis (NANBH). HCV is an RNA virus, unrelated to the hepatitis viruses, A, B, D, or E; it was first identified in 1989. Although most infections become chronic, and it may lead to chronic liver disease, most patients with HCV infection are asymptomatic. The predominant modes of transmission are by blood, blood products, or other parenteral exposure, particularly injecting drug use. More contentious is the role of sexual transmission, although evidence for this was provided by studies of NANBH.

OBJECTIVE

This review considers the evidence for sexual transmission, and the types of studies used to estimate the rate of transmission and the factors that may influence it.

METHOD

A Medline search using the keywords hepatitis C, sex, transmission, and prevalence in MeSH and free text. References in papers were searched, and some unpublished data identified. References were further selected to illustrate different methodologies.

FINDINGS

Evidence for sexual transmission is provided by several types of study including prevalence studies in groups at risk of other STDs, investigation of cases identified from surveillance reports, and cross sectional and longitudinal partner studies. Many studies are limited by their small size, the sensitivity and specificity of early assays, lack of controls, or the difficulty of excluding other routes of transmission. One prospective cohort study reported an incidence of 12 per 1000 person years in the sexual partners of HCV infected patients. 1-3% of partners of HCV infected patients are found to be infected in cross sectional studies. Co-infection with HIV, duration of the relationship, or chronic liver disease may be independent cofactors increasing the risk of transmission. A meta-analysis of selected studies may be informative, and further larger prospective studies are required. There is a small but definite risk of sexual transmission of hepatitis C.

Prevalence of serologic markers of HBV, HDV, HCV and HIV in non-injection drug users compared to injection drug users in Gran Canaria, Spain

Injection drug use (IDU) is one of the most significant risk factors for viral hepatitis (B, D and C) and human immunodeficiency virus (HIV) infection. However, there is little information about the risk of infection among non-injection drug users (non-IDUs). The present study was designed to perform several objectives: (a) to evaluate the prevalence of serological markers of hepatitis B, D, C virus and HIV in IDU and non-IDU patients; (b) to compare the prevalence of these markers between both groups; (c) to identify risk factors for HCV and HIV in this population; and (d) to correlate the presence of HCV and liver function. A total of 385 consecutive patients (122 IDUs and 263 non-IDUs), admitted to the Drug Dependency Treatment Unit at the Hospital Insular of Gran Canaria between 1993 to 1994, were included in the study. The serological markers of HBV, HDV, HCV and HIV were determined by ELISA and immunoblot methods. In all cases we also measured syphilis tests (RPR and FTAabs), serum aminotransferases and serum gammaglutamiltranspeptidase. Compared to the non-IDU, the IDU group presents a higher prevalence of antiHBc (55.0% vs. 20.7%, p < 0.0001), antiHCV (87.6% vs. 35.3%, p < 0.0001) and antiHIV (21.8% vs. 2.7%, p < 0.0001). There was no significant difference in RPR positivity (0.9% vs. 4.9%, p = 0.06). Delta infection was only detected in injection drug users, and the prevalence was low. Using logistic regression, the only risk factors associated with antiHCV positivity were injection drug addiction (OR: 9.2, 95% CI: 4.9-17.0) and antiHBc positivity (OR: 5.5, 95% CI: 3.0-9.9). Similarly, the associated risk factors for HIV were injection drug addiction (OR: 5.9, 95% CI: 2.3-15.0) and antiHBc positivity (OR: 3.8, 95% CI: 1.5-9.2). However, no correlation was found between antiHCV positive and antiHIV or between these markers and RPR positivity. Patients positive for antiHCV showed significant elevations in aspartate aminotransferase and alanine aminotransferase levels, when compared with patients negative for antiHCV: 65.0 vs. 39.2 U/l (p < 0.001) and 88.4 vs. 40.3 U/l (p < 0.001), respectively. We conclude that drug users have an elevated prevalence of HCV, HBV and HIV infection, even if drug use is only inhalated. On the other hand, the main risk factors associated with HCV and HIV are injection drug addiction and exposure to hepatitis B virus. Finally, in the study population, liver dysfunction is closely related to HCV infection.

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.

Therapy for chronic hepatitis B and C infection in haemophilia

Haemophiliacs, until recently, have been at risk of hepatitis B and C infection. Substantial numbers of patients remain persistently infected. Several lines of evidence suggest that these diseases will cause considerable morbidity unless therapy can successfully reduce viraemia and prevent disease progression. Cessation of viral replication may prevent progression to hepatic fibrosis.

Absence of hepatitis C virus transmission but frequent transmission of HIV-1 from sexual contact with doubly-infected individuals

Hepatitis C virus (HCV) is transmitted through infected blood and blood products, but evidence of other routes of transmission is less clearly understood. In a study designed to examine human immunodeficiency virus (HIV) transmission, the prevalence of HCV has also been measured. Sixty-one couples were analysed, 30 in which partners were at risk through sexual contact alone, of whom 12 (40%) became infected with HIV and none with HCV. Thirty-one partners were exposed sexually and additionally through intravenous drug use. Of these, 16 (52%) became infected with HIV and 25 (80%) contracted HCV infection. These findings support the evidence of others that HCV is only rarely transmitted by sexual intercourse in heterosexual relationships and that HIV is not a co-factor for HCV transmission.

Distribution of HCV genotypes in patients infected by different sources

To determine the distribution of hepatitis C virus (HCV) genotypes in our population within the Basque country, 58 HCV-infected patients were analysed. The predominant HCV genotype among subjects infected by blood transfusions (n = 9) and surgical procedures (n = 14) was 1b (88 and 50%, respectively). On the other hand, genotype 3a was the most common among intravenous drug users (n = 16), with data statistically significant (p < 0.0001). There were 18 patients (31%) with unknown risk factors, twelve of whom (66.7%) were infected with genotype 1b. Patients infected with genotype 1b were older than patients infected with genotype 3a (p < 0.0001). There existed a relationship between the HCV genotype and the source of infection.

Simultaneous detection of hepatitis C virus and human immunodeficiency virus RNA in serum using amplicor PCR tests

Several tests are currently available to assist in the diagnosis of the hepatitis C virus (HCV) and human immunodeficiency virus (HIV). Tests that actually detect or quantify these viruses are based on the polymerase chain reaction (PCR) technique. However, the application of PCR is limited by the cost, labor, time-consumption, and potential for contamination. In this article we describe some procedures developed to reduce these limitations. We have developed and validated simultaneous detection methods for HIV RNA and HCV RNA in single serum samples using Amplicor PCR tests. The sensitivity and specificity of this method are comparable with the results obtained with commercial reverse transcription polymerase chain reaction (RT-PCR) techniques for HIV and HCV RNA detection. In addition we have modified the HIV Amplicor test for the RT-PCR procedure and the Chomczynski's method of RNA isolation. We hope that our method can find same applications in HIV and HCV coinfection research, blood screening, and medical diagnosis.

Transfusion-transmitted disease

Many patients with haemophilia are infected with viruses, due to treatment with blood products--particularly from large pool clotting factor concentrates before 1985. AIDS in haemophilic patients was first described in 1982 and it has significantly reduced the life expectancy of these patients. Although no new sero-conversions have occurred since 1986, management of HIV in haemophilia remains a clinical challenge. Transfusion-associated hepatitis was recognized in 1943, and it is now an important complication of haemophilia treatment. Vaccination against HAV is recommended. Intensively-treated older haemophilic patients usually have serological evidence of HBV infection. HBV transmission has been stopped, but hepatitis B vaccination is still practised, because HDV requires HBV for propagation. Many patients are infected with HCV: before 1985 almost all patients who received clotting factor concentrate developed non-A, non-B hepatitis, now recognized as HCV. Treatment strategies are being developed for HCV in haemophilic patients. Parvo virus can be transmitted by clotting factor concentrate; it is very resistant to sterilization processes, transmission causing severe illness even in immuno-competent individuals. New blood-borne viruses responsible for sero-negative hepatitis include: GBV-A, B and C, and HGV. Although there is no link between CJD and haemophilia, there is concern about possible blood product transmission.

Hepatitis C

The hepatitis C virus (HCV) genome was isolated during the late 1980s using molecular cloning techniques. It is recognized as the cause of most cases of percutaneously transmitted non-A, non-B hepatitis. Prevalence of antibodies to HCV(anti-HCV) in the general Australian population is 0.3%. However, among regular intravenous drug users the prevalence exceeds 90%. The predominant risk factors for HCV are intravenous drug use, tattoos, exposure to blood products, occupational risk and ethnicity. In contrast to hepatitis B, sexual spread and vertical transmission of HCV from mother to neonate are relatively uncommon. The risk of acquiring HCV from a single HCV-contaminated needlestick accident is about 5%. Most cases of acute HCV infection are asymptomatic, but 50 to 80% progress to chronic disease. The percentage of those with chronic HCV progressing to cirrhosis is not accurately known, but is probably 20%. Treatment strategies for HCV, utilizing recombinant interferons, are proving useful in patients with mild to moderate liver disease, but fare less well in patients with cirrhosis. Currently, there is no vaccine for hepatitis C, so pre-exposure prophylaxis is not possible. Equally, no post-exposure intervention, for example with gamma globulin, has been shown to be beneficial, though there may be a role for early interferon therapy.

Risk of hepatitis C virus infection among household contacts of Saudi patients with chronic liver disease

To evaluate the intrafamilial transmission of hepatitis C virus and related risk factors among the Saudi population, two groups were investigated: 1) 20 index patients with chronic liver disease and their 127 family contacts, and 2) 20 blood donors who were anti-HCV-positive but with no chronic liver disease and their 91 family contacts. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for liver biochemistry and antibody to HCV (anti-HCV) by a third-generation enzyme immunoassay (UBI HCV EIA4.0). Only two spouses of 20 index patients were anti-HCV-positive while the remaining 125 family contacts were anti-HCV-negative. None of the 91 family contacts of the 20 anti-HCV-positive blood donors was anti-HCV-positive. The two spouses were wives of index patients but had a history of blood transfusion on at least two different occasions. Our results clearly indicate the intrafamilial transmission of HCV is not the route of transmission of HCV among Saudis and our results argue against sexual transmission of hepatitis C virus despite a relatively long duration of marriage.

Donor-to-donor and donor-to-patient transmission of hepatitis C virus

A patient was reported with suspected acute post-transfusion hepatitis C virus (HCV) infection, 5 months after the transfusion of 2 units of red cells. The archived serum samples of the two implicated donations were retested by the original 3rd-generation assay together with another 3rd-generation assay and RI-BA III, and were tested for HCV RNA using the PCR. Both donations were anti-HCV negative but one was found to be PCR positive. This donor was a regular donor and was identified as the husband of a donor identified 18 months earlier as being HCV positive. This case is an example of transmission of HCV in the window period of infection, and a probable example of the transmission of HCV from wife to husband through intimate contact.

Detection of HCV RNA in serum and seminal fluid from HIV-1 co-infected intravenous drug addicts

The presence of hepatitis C virus (HCV) RNA in serum and seminal fluid was investigated in eleven drug addicts coinfected with HIV-1 and HCV. Serum and seminal fluid were taken from each patient at the same time point. HCV RNA was found in ten of the eleven serum samples tested, but only in one of the semen samples. No relationship was observed between CD4 cell counts, the stage of HIV infection, extent of liver damage and the presence of HCV RNA in serum and semen. The results indicate that HCV is not usually present in the semen and provide further evidence against sexual transmission as an important mode of transmission of HCV infection.

Heterosexual activity as a risk factor for the transmission of hepatitis C virus

Hepatitis C virus (HCV), the major causative agent of non-A, non-B hepatitis, is transmitted by parenteral exposure. Transmission by sexual activity, however, is controversial. Possible behavioral risk factors for HCV infection were studied retrospectively among imprisoned men (n = 201, mean age: 45 years [S.D. 13]) who visited a health service center at a Japanese correctional facility for medical examination. Seropositivity of anti-HCV antibody was disproportionately high (49.8%) in comparison with volunteer blood donors. Among possible risk factors significant on univariate analysis, intravenous drug abuse and Tama-Ire, a Japanese custom of sexual behavior that suggests frequent, aggressive or promiscuous heterosexual activity, proved to be independent risk factors for HCV infection (odds ratio = 7.39, 95% CI = 3.41 - 16.05, P < 0.0001; odds ratio = 3.16, 95% CI = 1.16 - 8.64, P = 0.026, respectively) as shown by logistic regression analysis. The data suggest that HCV may be transmitted by sexual activity.

Methods of transmission of hepatitis C

The route of transmission of hepatitis C virus is still controversial. Parenteral exposure via blood or blood products leads to infection in the majority of cases, and the majority of intravenous drug users become infected by repetitive exposure to contaminated injection equipment. The risk of infection from a single needlestick injury is 5-15% and may depend on the size of the innoculum. Other parenteral routes of transmission may include traditional healing practices and the use of contaminated medical equipment. Transmission is less common within a family but the prevalence of hepatitis C viral antibodies is higher in family members and sexual partners of carriers than in the general population. There are some well-documented instances of acute hepatitis C occurring after a defined sexual exposure. Vertical transmission is rare unless the mother has high levels of circulating HCV RNA as may occur in those also infected with HIV. The detection of hepatitis C in saliva and the higher than expected prevalence of infection in dentists may point to the possibility of transmission by salivary contamination. There remain large numbers of hepatitis C carriers in whom no route of infection can be identified.

Molecular epidemiology of hepatitis C virus infection amongst intravenous drug users in rural communities

The prevalence of hepatitis C virus (HCV) infection amongst a group of intravenous drug users (IVDUs) resident in West Suffolk (East Anglia, England) was investigated and compared with the prevalence of infection with hepatitis B virus (HBV) and human immunodeficiency virus (HIV). In addition, both the level of HCV persistence, as defined by detection of viral RNA, and the HCV genotypes present in this population were determined. It was found that HCV antibodies were present in 59% of those tested; by comparison 22% had antibodies to HBV and 1% antibodies to HIV. HCV RNA was found in 44% of those with HCV antibody. HCV genotype 1 was the most prevalent within this population although both genotypes 2 and 3 were also represented.

Molecular analysis of intraspousal transmission of hepatitis C virus

BACKGROUND/AIMS

Although intraspousal transmission of hepatitis C virus (HCV) has been speculated, there is no direct evidence.

METHODS

To investigate whether transmission of HCV occurs by this route, 295 spouses of persons diagnosed with HCV were studied. Of these, 25 (8.8%) tested positive for anti-HCV. Next, the HCV genotype was determined by polymerase chain reaction using a mixed primer set, and cDNA was obtained in 17 of the 25 couples for comparison of the genotypes.

RESULTS

Of these 17, 14 (82.4%) spouses were shown to be infected with HCV of the same genotype. Analysis of the nucleotide sequences of putative E1 gene of eight couples having the same HCV genotype revealed that five couples had remarkably high nucleotide sequence homologies (> 97%), whereas samples obtained from the remaining three couples showed relatively low homology (91-92%). Nucleotide sequence homologies were significantly higher between spouses than between non-spouse pairs of isolates. Phylogenetic analysis using the neighbor-joining method suggests that infection in these five couples probably occurred after marriage. Furthermore, none of the five couples had shared other possible transmission routes such as intravenous drug use, dental treatment or acupuncture.

CONCLUSION

These data strongly suggest the occurrence of intraspousal transmission of HCV.

Prevalence of HBV, HDV and HCV hepatitis markers in HIV-positive patients

Since HIV infection could condition the natural history of parenterally transmitted viral hepatitis (HBV, HCV, HDV), with possibly differing effects in different risk groups, we decided to retrospectively examine sera from a cohort of 637 HIV seropositive patients in different stages of infection, seen from 1985 to 1992, to study the prevalence and temporal course of these infections. Virological markers of HBV, HCV and HDV were determined by ELISA and RIBA methods. The severity of HIV infection was higher in homosexuals than in drug addicts. Prevalence of antiHBc antibodies was 82% in drug addicts and 77% in homosexuals, whereas antiHCV antibodies prevalence was 72% in drug addicts and only 7% in homosexuals (p < 0.000001). When only antiHBc-positive patients were considered, there was a significant difference in antiHBs antibodies between drug addicts (DA) and homosexuals (OR for DA 0.29, 95% CI 0.08/0.83, p = 0.02), suggesting that drug addicts are less able to produce a protective response. This fact cannot be explained by the severity of HIV infection (which was higher among the homosexual group) and suggests some immunodepressive effect of drug abuse. Delta infection was only detected in the drug addict group, and the prevalence was low. Finally, we cannot confirm the interference of HCV infection with the speed of HBsAg clearance: in this study the prevalence of HBsAg was almost the same in HCV-positive and negative patients.

Acute hepatitis C infection after sexual exposure

A case is described of a woman with acute hepatitis C infection whose partner had chronic hepatitis C infection and where heterosexual contact was the only major risk factor. Infection of both partners was confirmed serologically and by the finding of virus RNA by reverse transcription and polymerase chain reaction amplification. Nucleotide sequence analysis of the NS5 region (RNA polymerase) was used to show that both partners were infected with virus of the same genotype (1a). The nucleotide sequence of virus RNA found in the female patient is closest to variants cocirculating in the male contact, consistent with transmission having occurred between the two.

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.

Epidemiology of hepatitis C virus in western Venezuela: lack of specific antibody in Indian communities

Hepatitis C virus (HCV) is transmitted mainly by the parenteral route after percutaneous exposure to virus-infected products or body fluids. Thus, HCV shares with hepatitis B and D (HBV, HDV) viruses this common transmission route. The prevalence of antibody against HCV (anti-HCV) was studied in 1155 serum samples from individuals at risk of infection by bloodborne or sexually transmitted agents, as well as from others lacking such risk factors, from the city of Maracaibo, Venezuela. Anti-HCV and serological markers of infection by HBV and HDV were also studied in further 550 samples taken from Bari Indians living in different communities in the Perijá mountains, State of Zulia, Venezuela. The results obtained showed that recipients of blood or blood products are at increased risk of HCV infection in Maracaibo, whereas sexual transmission plays only a minor role if any. Both HBV and HDV infections were highly prevalent among Bari Indians (64.4% positive for anti-HBc; 11.1% of HBsAg carriers; 15.3% positive for anti-HDV among HBsAg carriers). No anti-HCV positive samples were, however, detected among them, thus suggesting either that HCV has not still reached this population or that HBV and HDV are transmitted by routes unshared by HCV. Anti-HCV was also absent among samples from mentally retarded patients from Maracaibo, thus confirming similar findings from other countries and supporting the existence of specific transmission mechanisms for HBV and HDV which are not working for HCV.