Acute hepatitis C infection after sexual exposure

The Association between Female Genital Cutting and Spousal HCV Infection in Egypt

Objective. To identify the risk factors for HCV infection within married couples in Egypt. Methods. In 2008 Egypt conducted its first nationally representative survey of HCV prevalence. 11126 of the 12780 individuals aged 15-59 year who were sampled agreed to participate and provided information via a questionnaire about demographic and behavioural characteristics and blood for HCV antibody and RNA analysis. We assessed the risk factors for HCV infection in a subsample of 5182 married individuals via multivariate logistic regression. Results. Overall HCV antibody prevalence in the married couples was 18.2% (95% CI, 16.8-19.6). HCV antibody prevalence was higher in the husbands (23.7%) than the wives (12.1%; P < 0.001). Having a spouse who was infected with HCV was an independent risk factor for HCV infection with odds ratios of 2.1 (95% CI, 1.6-2.9) and 2.2 (95% CI, 1.6-3.1) for women and men, respectively. Husbands whose wives had experienced female genital cutting (FGC) had a higher prevalence of HCV and this relationship was driven by a strong association in urban areas. Amongst the women there was no association between FGC and HCV overall but in urban areas only women who had experienced FGC were HCV infected. Conclusions. This study provides additional evidence of the importance of intrafamilial transmission of HCV in Egypt.

Hepatitis C virus and human immunodeficiency virus transmission routes: Differences and similarities

Bouare et al found that hepatitis C virus (HCV) infection in Malian women is mainly transmitted through medical procedures with contaminated supplies, and that human immunodeficiency virus (HIV) transmission is predominantly sexual. The results of this study confirm those of a recent case-control study in New York and Oregon which demonstrated that healthcare exposures represent an important source of new HCV infections in United States. HCV seroprevalence was only 0.2% in pregnant, young Malian women, indicating that hygiene improved in healthcare facilities over time. Heterosexual transmission of HCV is exceptional, and can occur, from males to females, in extremely rare occasions in case of vaginal mucosal damage or less rarely through anal intercourse. The Malian study did not show an association between HIV infection and hospitalization, transfusion, tattoo, dental care. Transmission by needle-stick injury occurs in 0.9%-2.2% of exposures from HCV-infected subjects and in 0.1%-0.3% of exposures from HIV-infected individuals. HCV is therefore more transmissible through percutaneous exposure.

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.

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.

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.

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.

Association of hepatitis C virus infection with sexual exposure in southern India

To determine the association between sexual exposure and hepatitis C virus (HCV) infection in urban Chennai, India, a random sample of adults who live in a slum community completed interviews and provided samples to test for HCV, herpes simplex virus type 2 (HSV-2), and other sexually transmitted infections (STIs). All analyses excluded recent and current injection drug users. HCV infection was not associated with the reported number of sex partners for men or women. Women were more likely to be HCV infected if they reported previous genital ulcer disease (adjusted odds ratio [AOR], 3.88; 95% confidence interval [95% CI], 0.94-16.0; marginally statistically significant). Men were more likely to be HCV infected if they were HSV-2 infected (AOR, 3.85; 95% CI, 1.18-12.6) or reported having had sex with men (AOR, 3.61; 95% CI, 1.00-13.1). Sexual transmission of HCV infection may be facilitated by ulcerative STIs and male-male sexual practices, but it appears to occur infrequently in this population.

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.

Higher prevalence of anti-HCV antibodies among HIV-positive compared to HIV-negative inhabitants of Addis Ababa, Ethiopia

Serum samples (n = 4,593) collected in 1994 as part of a representative household community survey of the population of Addis Ababa who were 0-49 years old were tested for hepatitis C (HCV) antibodies. A third generation ELISA was used for primary screening and a line immunoblot assay for confirmation. HCV antibody prevalence was 0.9% (95% CI, 0.6-1.2%) and higher among HIV-positive compared to HIV-negative individuals (4.5% vs. 0.8%, respectively, P < 0.001). Similar higher prevalence of HCV antibodies was seen among HIV-positive compared to HIV-negative antenatal care attenders (2.9% vs. 0.8%, respectively, P = 0.003, n = 1,725), and sex workers (5.3% vs. 1.3%, respectively, P = 0.02, n = 383). Such association between HCV and HIV infection has not been described previously in Africa. After stratification by HIV status, HCV prevalence among women of the general population was identical to that of sex workers, suggesting that HCV sexual transmission is not common in this population and that HIV infection does not enhance susceptibility to HCV sexual transmission.

Infectious hepatitis C, hepatitis G, and TT virus: review and implications for dentists

In the past 10 years, hepatitis C and G viruses have been identified, and in the last two years a further parenterally transmitted agent, termed TT virus (TTV), has been discovered. These viruses have a worldwide distribution and frequently cause chronic infection. The purpose of this article was to promote an understanding of these viral agents and their relevance in dental practice. Infected patients may develop a chronic carrier state without clinical disease or may develop liver disease, and may have related oral conditions. Dental providers will see a growing number of patients with HCV/HGV and possibly TTV infection. All of these patients require appropriate infection control measures during dental treatment.

Vaginal shedding of hepatitis C virus

A group of 14 women infected with hepatitis C virus (HCV) was evaluated for vaginal shedding of the virus. The HCV-RNA detection was performed in plasma, peripheral blood mononuclear cells (PBMC) and in supernatant and pellet of vaginal washings. HCV-RNA positive results were obtained in all plasma samples, in 57% of the PBMC samples, in 36% pellets obtained following centrifugation of vaginal washings and in 36% of the supernatants. In 21% of the women a positive result was found, at the same time, in every analysed product. The HCV genotypes identified in the plasma samples (1a: 38%; 1b: 36%; 3a: 13% and 1b+3a: 14%) matched with those in PBMC and vaginal washings in every sample, with the exception of cases where mixed infection (1b+3a) was detected. In these, genotype 1b was only detected in plasma. HCV viral load was not associated with the presence of HCV-RNA in PBMC or in vaginal washings (either cells or supernatant).

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.

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.

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.

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.

Hepatitis C virus and oral disease: a critical review

Hepatitis C virus (HCV) infection is widespread with an estimated 3% of the world population being infected. Acute infection is usually mild but chronicity develops in as many as 70% of patients, of whom at least 20% will eventually develop cirrhosis. A further 1-4% of cirrhotic individuals will develop hepatocellular carcinoma. Infection with HCV may have effects on various organs other than the liver. HCV has been causally associated with a remarkable array of extrahepatic manifestations, some of which remain unproven. This review discusses the evidence implicating HCV in the aetiology of two important oral conditions, namely Sjögren's syndrome and lichen planus.

Evaluation of a disinfection procedure for hysteroscopes contaminated by hepatitis C virus

We assessed the ability of a standard disinfection procedure to eliminate hepatitis C virus (HCV) from the air-water channel of hysteroscopes. The residual HCV RNA remaining after the disinfection procedure was measured by polymerase chain reaction. When correctly applied to hysteroscopes, the standard disinfection procedure was sufficient to eliminate the risk of HCV transmission.

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.

Hepatitis C virus infection: Review and implications for the dentist

OBJECTIVE

The purpose of this report was to review the current literature on hepatitis C virus infection, with particular attention to the aspects of interest for dental health care staff.

MATERIAL AND METHODS

The authors searched original research and review articles on specific aspects of hepatitis C virus infection, including articles on virology, epidemiology, transmission, diagnosis, natural history, extrahepatic manifestations, therapy and oral aspects of hepatitis C virus infection. The relevant material was evaluated and reviewed.

RESULTS

Hepatitis C virus is an RNA virus that is present throughout the world and has major geographic variations. The virus, transmitted mainly by means of blood contact, causes chronic hepatitis in up to 80% of cases and may give rise to hepatic cirrhosis and hepatocellular carcinoma in a significant proportion of patients. Although it is of limited efficacy, interferon alpha is currently the drug of choice in the treatment of the infection. Hepatitis C virus infection is associated with a number of extrahepatic manifestations that may include oral diseases such as lichen planus or sialadenitis. Although there are documented cases of nosocomial transmission to health care workers after percutaneous exposure, the prevalence of hepatitis C virus among dental staff members is probably similar to that in the general population.

CONCLUSION

Hepatitis C virus infection is a relatively common infection worldwide (1.4% in the US general population) that causes significant chronic hepatic disease. The dentist is thus likely to face a growing number of patients with a diagnosis of hepatitis C virus infection. For this reason it is essential for dental health care workers to be aware of the principal features of the disease and of its oral and dental implications.

Hepatitis C

Hepatitis C virus (HCV) infection afflicts millions of people in the United States and worldwide. We examine the epidemiology of HCV infection, the molecular biology of the virus, the pathophysiology of infection, the clinical diagnosis and manifestations of infection, and the treatment of HCV infection.

Interferon therapy for acute hepatitis C viral infection--a review by meta-analysis

BACKGROUND

Hepatitis C viral (HCV) infection poses a major health problem for Australia. Currently interferon therapy is approved only for people with chronic infection, yet the literature contains a number of studies that show that there is a better response to interferon in symptomatic acute HCV.

AIM

To review the response to interferon therapy in acute HCV by way of meta-analysis.

METHODS

This study was a retrospective review of the data on the use of interferon therapy in acute HCV. The meta-analysis was performed using the methods of DerSimonian and Laird. Data were presented by calculating the risk difference which estimated efficacy by calculating the proportion of patients in treatment groups who responded better (0 to +1.0) or worse (0 to -1.0) than untreated control groups.

RESULTS

A meta-analysis of six studies on the use of 3MU of interferon alpha 2b (IFN-alpha 2b) three times a week for six to 24 weeks showed a significant response as measured by long term (> 12 months) normalisation of alanine aminotransferase (ALT) and clearance of HCV RNA (as measured by polymerase chain reaction). The risk of difference was +0.31 (95% CI of +0.19 to +0.43, p < 0.01) and +0.33 (95% CI of +0.08 to +0.58, p < 0.001) respectively. Slightly better results were seen with daily doses of 3MU of interferon beta (IFN-beta) given intravenously over four to seven weeks. This produced a risk difference of +0.57 (95% CI of +0.26 to +0.88, p < 0.02) for normalisation of ALT and +0.83 (95% CI of +0.61 to 1.00, p < 0.001) for clearance of HCV. Results for higher daily doses of both IFN alpha and beta were limited to a few studies and most were uncontrolled. 6MU of IFN-alpha 2b three times a week for 16 to 24 weeks produced a risk difference of +0.53 (95% CI +0.17 to +0.89, p < 0.05) for normalisation of ALT and +0.44 (95% CI +0.06 to +0.82) for clearance of HCV RNA. Results with 6MU daily for eight weeks of IFN-beta in an uncontrolled study, showed up to 90% patients cleared HCV long term. Preliminary results with 10MU of IFN-alpha 2b daily for four to six weeks also showed long term clearance of HCV RNA and normalisation of ALT in 90% of treated patients.

CONCLUSION

Short term (six weeks to six months) treatment of symptomatic acute HCV with interferon (both alpha and beta) produced a better long term response rate than prolonged therapy (> 12 months) in chronic HCV. Daily doses of 6MU and 10MU produced better responses than 3MU but more studies are needed to determine the optimum regime.

Review: molecular epidemiology of hepatitis C virus

Molecular techniques have been used to investigate the epidemiology of hepatitis C virus (HCV) at several different levels. At a global level, the time of divergence of the diverse HCV genotypes isolated from different geographical regions has been estimated from the rate of divergence observed among a cohort of individuals infected from a common source. Estimates of more than 300 years for virus subtypes and more than 500-2000 years for virus types are consistent with their current geographical distributions. Analysis of virus sequences has also provided evidence for a common source of infection in several large-scale outbreaks of HCV infection, although where there is evidence that the implicated source contains more than one variant it may be difficult to distinguish individuals infected by different sources. Finally, sequence analysis has been used to investigate the vertical or horizontal transmission of HCV between pairs of individuals. The hypervariable region of the E2 gene is the most informative region to study if samples are available soon after the transmission event, but evidence for more distant events can still be obtained from analysis of genes such as NS5b and E1. Interpretation of some studies is complicated by the conservation of the gene region studied, or by the failure to make comparisons with sequences from epidemiologically unrelated viruses.

Hepatitis

Hepatitis is a diagnosis that can easily be missed by the physician. The morbidity of this disease is significant when one takes into account all the cases that either do not have a typical presentation or are misdiagnosed. The emergency physician bears substantial responsibility in the diagnosis and intervention of patients with hepatitis, and needs to develop a systematic way of approaching the patient with a viral syndrome or other vague complaints that will allow appropriate consideration of this diagnosis.

Virology of hepatitis C virus

Hepatitis C virus (HCV) has been identified as the main causative agent of posttransfusion non-A, non-B hepatitis. Through recently developed diagnostic assays, routine serologic screening of blood donors has prevented most cases of posttransfusion hepatitis. The purpose of this paper is to comprehensively review current information regarding the virology of HCV. Recent findings on the genome organization, its relationship to other viruses, the replication of HCV ribonucleic acid, HCV translation, and HCV polyprotein expression and processing are discussed. Also reviewed are virus assembly and release, the variability of HCV and its classification into genotypes, the geographic distribution of HCV genotypes, and the biologic differences between HCV genotypes. The assays used in HCV genotyping are discussed in terms of reliability and consistency of results, and the molecular epidemiology of HCV infection is reviewed. These approaches to HCV epidemiology will prove valuable in documenting the spread of HCV in different risk groups, evaluating alternative (nonparenteral) routes of transmission, and in understanding more about the origins and evolution of HCV.

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.