Risk Factors For Hepatitis C Virus Transmission Research Articles

Risk Factors for the Transmission of Hepatitis C Virus Infection in the Turkish Population

The risk factors for the transmission of hepatitis C virus (HCV) infection varies substantially between countries and geographic regions. The aim of this investigation was to determine the risk factors which may be involved in the transmission of HCV infection in the Turkish population. This study included patients who were admitted to the Department of Gastroenterohepatology, Istanbul Medical Faculty, Istanbul University, between 1996 and 2002 and found to be anti-HCV positive during hospitalization or during follow-up as outpatients. All patients were asked about risk factors for HCV transmission including transfusion, history of operation, hospitalization, hemodialysis, intravenous drug use, suspected sexual contact, tattooing, acupuncture, dental procedures, manicure and pedicure, blood brotherhood rituals, perinatal risk factors, common circumcision rituals, and history of abortion. In our study, total of 320 patients with anti-HCV seropositivity were involved. The numbers and percentages of male and female patients were 139 (43.4%) and 181 (56.6%), respectively. The mean age of the patients was 49.7+/- 12.4 years (range: 18-73 years). HCV-RNA was found to be positive in 297 (92.8%) patients. The most common risk factor was a history of surgery (305; 98%), and the second most common was blood transfusion (123; 39.7%). The numbers and percentages of patients for the other risk factors were as follows: dental procedure, 86 (27.5%); abortion, 66 (21.2%); long-term hospitalization, 37 (11.6%); hemodialysis, 31 (10%); history of jaundice, 15 (4.6%); history of intravenous drug abuse, 10 (3.1%); history of suspected sexual contact, 5 (1.5%); history of manicure and pedicure, 4 (1.2%); history of occupational transmission, 3 (0.9%); history of tattooing, 2 (0.6%); history of acupuncture, 2 (0.6%); circumcision in a common circumcision ritual, 1 (0.3%); and percutaneous needle puncture, 1 (0.3%). None of the patients had a history of blood brotherhood ritual or perinatal transmission. Only one risk factor was detected in 73 (22.8%) patients, two risk factors were detected in 122 (38.2%) patients, three risk factors were detected in 78 (24.5%) patients, and four risk factors were detected in 39 (12.2%) patients, however, in 8 (1.6%) patients no risk factors could be found. In Turkey, the most common risk factor for the transmission of HCV infection is surgery, which can be preventable.

Hepatitis C Virus Risk Factors in the Turkish Community

Hepatitis C virus (HCV) is the most common chronic blood-borne infection in the worldwide. This infection is often insidious and one-half of infected patients are asymptomatic. Determination of risk factors for HCV transmission is very important. The aim of this study was to assess the risk factors, transmission to spouses and children for HCV infection in Turkish population. One hundred and fifty-one patients with chronic hepatitis C and 151 control cases were investigated for the probable risk factors of HCV infection. Complete blood count, ALT, AST, albumin, prothrombin time, upper abdomen ultrasonography assessment and percutaneous liver biopsy (not for cirrhotics) were performed in all patients with chronic hepatitis C. Anti-HCV testing was done by using second-generation ELISA in 302 cases. Minor surgical operation (p < 0.001), major surgical operation (p = 0.001), blood transfusion (p < 0.001), multi-partner sex (p < 0.05), frequent dental therapy (p < 0.05), and dental extraction (p < 0.001) in patients with a chronic HCV infection were found to be higher than the control group. No significant difference was found in other risk factors. The rate of hepatitis C virus in index cases was found to be 1.8% in their spouses and 1.2% in their children. Our study showed that surgical operation, frequent dental therapy, dental extraction, multi-partner sex, and blood transmission are the main risk factors for HCV infection in Turkish community.

Risk Factors for Hepatitis C on the Texas-Mexico Border

Our clinical experience suggested that hepatitis C virus (HCV) infection in this Texas-Mexico border area might have features, especially risk factors, that differ from some other areas of the United States. Therefore, we conducted a prospective analysis to investigate the epidemiology, risk factors, and certain other characteristics of HCV infection in the El Paso region. During a 2-yr period, individuals with a positive HCV serology were considered as "patients" and those with a negative hepatitis serology panel were "controls." A questionnaire survey was conducted in person or by telephone with individuals (patients and controls) who agreed to participate in the interview process. We identified and interviewed 320 patients and 307 controls. All of the contacted patients and controls agreed to be interviewed. Many established and potential risk factors for HCV transmission were documented in the patients. Furthermore, multiple potential risk factors were often present in individual patients. However, on multivariate analysis only injection drug use, blood transfusion, and tattooing were found to be significant independent risk factors for HCV infection. In the great majority of patients, tattoos were applied by friends (including gang members), inmates in jail/prison, or self, rather than commercial parlors. Tattooing is an independent risk factor for HCV infection in this United States-Mexico border area. The role of nonsterile tattooing practices in HCV transmission merits additional examination in regard to precise risk settings, frequency, and mechanisms of infection.

Nosocomial transmission of HCV in the liver unit of a tertiary care center

Despite its medical and legal implications, there are no prospective studies analyzing the incidence and mechanisms involved in the nosocomial transmission of hepatitis C virus (HCV) in liver units. This study prospectively investigates the nosocomial transmission of HCV in the liver unit of a tertiary care center from August 2000 to October 2002. The median prevalence of HCV infection among hospitalized patients was 50%. Anti-HCV-negative patients admitted to the liver unit during the study period were prospectively followed, and serum markers of HCV infection were repeated 6 months after discharge. All known risk factors for HCV transmission (including the physical allocation of HCV-infected and noninfected patients during hospitalization) were recorded. Complete follow-up data were available in 1301 (84.5%) of 1540 patients. Six patients (0.46%) acquired HCV infection (annual incidence: 0.27/100 admissions). Phylogenetic analyses of recovered HCV sequences identified the source of infection as an HCV-infected roommate (3 cases) and a patient receiving care by the same nurse team (1 case). The most relevant risk factors associated with HCV acquisition were duration of hospitalization (>10 days; OR, 35; 95% CI, 1.96-622) and hospitalization with an HCV-infected roommate (>5 days; OR, 12; 95% CI, 1.39-103). In fact, HCV infection occurred in 1.7% of the 357 patients hospitalized longer than 10 days. In conclusion, HCV nosocomial infection appears to occur via patient-to-patient transmission in liver units, particularly in individuals who require long hospitalizations. Continuous reinforcement of universal prevention measures and, when possible, isolation of patients at higher risk might further reduce nosocomial HCV transmission.

The epidemiology and natural history of hepatitis C virus infection.

Hepatitis C virus (HCV) infection is the most common chronic blood-borne infection in the United States. HCV infection is generally benign in its acute stage but tends to become chronic in more than 70% of patients, at which stage it can induce liver cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Approximately 2.7 million Americans are estimated to have chronic HCV infection. Although the incidence of HCV infection is believed to be falling, the prevalence of HCV-related liver disease is rising. Better identification of risk factors for HCV transmission and improved understanding of the infection's natural history should refine measures for preventing the spread of infection and preventing complications in those infected.

Prevalence of antibodies to hepatitis C virus among hemodialysis patients in Damascus, Syria.

Evaluation of the epidemiology of hepatitis C virus (HCV) infection was made possible by the development of a serological assay to detect antibodies to epitopes of HCV. Hemodialysis (HD) is considered to be one of the main risk factors of HCV transmission. Therefore, the prevalence of antibodies to HCV (anti-HCV) was studied in patients undergoing maintenance dialysis therapy. Anti-HCV were detected using a third-generation assay. The study group consisted of HD patients, transplant recipients and staff members from two dialysis units in Damascus, Syria. The overall prevalence of anti-HCV among HD patients was 48.9%; 24.4% in one center (Al-Mouassat Hospital) and 88.6% in the other (Kidney Hospital). There was a significant correlation between prevalence of anti-HCV and duration of HD. The prevalence was 36.7% for patients on HD for < 3 years and 65% in patients on HD for > 3 years (p < 0.05). There was a significant correlation between anti-HCV positivity and elevated liver enzymes: alanine aminotransferase (ALT) and asparate aminotransferase (AST). However, there was no significant correlation between anti-HCV positivity and history of blood transfusion, exposure to hepatitis B virus, age and sex. The prevalence of anti-HCV among kidney transplant recipients was 48%, among staff members of the dialysis units it was 5.8%. Factors related to infrastructure and operational system might be responsible for the very high prevalence of anti-HCV found in one of the two units. There was no data available on anti-HCV status of transplant recipients prior to transplantation. However, the prevalence among those patients, which is very similar to that of HD patients, suggests that HD may be responsible for such high prevalence among this group. An intensive educational program for staff members and proper evaluation of the HD situation in the two units are needed.

The detection of hepatitis C virus in South Hungary.

More than 100 million people are infected with hepatitis C virus (HCV) worldwide. The prevalence of HCV infection varies from country to country and the natural history of hepatitis C infection is not well understood. The prevalence of anti-HCV positive blood donors in South Hungary was determined. Potential risk factors of HCV transmission were investigated and compared to anti-HCV-negative blood donors. Furthermore, the rate of anti-HCV positivity in children who had received one or more blood transfusions prior to the implementation of anti-HCV blood donor screening was evaluated. A total of 45719 blood donors and 120 children were tested for the presence of anti-HCV antibodies by second- and third-generation enzyme immunoassays. Positive results were confirmed by a recombinant immunoblot assay. Data on potential sources of HCV transmission were obtained by interviews. Among blood donors, the rate of confirmed HCV antibody-positives was 0.4% (195 of 45719 donors). Previous surgery, transfusion, more than three pregnancies, and tattoos were significantly correlated with confirmed anti-HCV positivity. Two of 120 children (1.7%) were confirmed anti-HCV positives. In both of them, serum HCV RNA could be detected. The prevalence of anti-HCV positive blood donors in South Hungary is low. Nosocomial infections and tattooing were found to be the most important risk factors for transmission of HCV. Because of the low prevalence of anti-HCV positive blood donors, only a small number of children, who received blood transfusions prior to the implementation of anti-HCV blood donor screening, are infected with HCV.

Routine serologic testing for hepatitis C virus infection should be instituted among dialysis patients.

Since the cloning of hepatitis C virus (HCV), a number of serologic and virologic tests for detecting infections with this virus have been made available for clinical practice. This led to the recognition of HCV as a major health hazard in hemodialysis (HD) centers. Yet the nephrology community has not been offered explicit recommendations about routine serologic testing for HCV of dialysis patients and consequently has remained unclear and divided about the utility of this testing. This review presents evidence in support of instituting routine serologic testing for HCV among dialysis patients. It concludes that because of the peculiar features of HCV infection in HD patients, serologic testing for HCV is the only means for unequivocal diagnosis of hepatitis C and an irreplaceable instrument for monitoring the incidence and the prevalence of the infection in this population. Serologic surveillance for HCV infection is crucial for identifying the association of new cases of HCV infection with potential risk factors for HCV transmission, particularly nosocomial, that can be modified in a way to prevent further dissemination of the virus. Data collected from routine serologic testing for HCV will undoubtedly improve our understanding of the epidemiology of HCV in the dialysis population and will provide a strong foundation for developing preventive measures and infection control strategies that are highly effective in controlling HCV infection. Routine serologic testing for HCV is also of direct benefit to the individual patient since establishing the HCV serologic status of each patient is important for optimizing patient care.

The role of parenteral antischistosomal therapy in the spread of hepatitis C virus in Egypt

The population of Egypt has a heavy burden of liver disease, mostly due to chronic infection with hepatitis C virus (HCV). Overall prevalence of antibody to HCV in the general population is around 15-20%. The risk factor for HCV transmission that specifically sets Egypt apart from other countries is a personal history of parenteral antischistosomal therapy (PAT). A review of the Egyptian PAT mass-treatment campaigns, discontinued only in the 1980s, show a very high potential for transmission of blood-borne pathogens. We examine the relative importance of PAT in the spread of HCV in Egypt. The degree of exposure to PAT by cohort was estimated from 1961-86 Ministry of Health data. A cohort-specific exposure index for PAT was calculated and compared with cohort-specific HCV prevalence rates in four regions. HCV prevalence was calculated for 8499 Egyptians aged 10-50 years. A significant association between seroprevalence of antibodies to HCV and the exposure index (1.31 [95% CI 1.08-1.59]; p=0.007) was identified across four different regions. In all regions cohort-specific HCV prevalence was lowest in children and young adults than in older cohorts. These lower prevalence rates coincided with the gradual and final replacement of PAT with oral antischistosomal drugs at different points in time in the four regions. The data suggest that PAT had a major role in the spread of HCV throughout Egypt. This intensive transmission established a large reservoir of chronic HCV infection, responsible for the high prevalence of HCV infection and current high rates of transmission. Egypt's mass campaigns of PAT may represent the world's largest iatrogenic transmission of blood-borne pathogens.

Changes in the epidemiology of hepatitis C infection in Germany: Shift in the predominance of hepatitis C subtypes

Hepatitis C virus (HCV) subtype distribution was studied in 395 chronically infected patients from Germany. HCV genotype 1 was most frequent (80.5%). One hundred forty-three individuals (36.2%) were infected with subtype 1a and 175 (44.3%) were suffering from subtype 1b infection, respectively. HCV subtype 3a was found in 53 (13.42%) persons. Subtypes 2a, 2b, and 2c have been detected in 5 (1.27%), 10 (2.53%), and 4 (1.01%) individuals. Genotypes 4 and 5a accounted for HCV infections in 4 (1.01%) and 1 (0.25%) subjects. There was a notable variation in the distribution of the prevalent subtypes 1a and 1b in different age groups. Subtype 1a was detected in 53.3% and 68.0% of patients aged 1-10 and 11-20 years, whereas subtype 1b in the same groups was present only in 33.3% and 28.0% of patients, respectively. In contrast, in individuals older than 50 years subtype 1b was most frequent. Thus, subtype 1b has been gradually substituted for subtype 1a during the last 20 years. Logistic regression analysis with adjustment for sex and different modes of HCV acquisition demonstrated that age of the infected subjects was a direct explanatory variable for subtype 1a and 1b distribution. Therefore, the observed shift in HCV subtype prevalence could not be attributed to changes in the epidemiological relevance of different known risk factors of HCV transmission, as had been assumed in previous studies. The altered subtype pattern reported here may have a profound influence on the future epidemiology of HCV infection.

MOTHER-TO-CHILD HEPATITIS C VIRUS TRANSMISSION IN WOMEN SERONEGATIVE FOR HIV-1

187 Mother-to-child Hepatitis C virus (HCV) transmission has been extensively studied in mothers with HIV-1 infection but few is known on the risk of HCV infection in children born to HIV-1 seronegative women. In order to assess the item, a multicenter prospective study was undertaken in Tuscany, Italy. Mother-to-child HCV transmission was investigated in 403 children born to anti-HCV positive anti-HIV-1 negative mothers in a median follow-up of 28(range 24-38) months in order to evaluate risk factors for HCV transmission. Thirteen children born to 275 HCV RNA-positive women acquired the infection. The transmission rate was 4.7% (95% confidence limit: 2.2-7.2%). None of the 128 children born to HCV RNA negative mothers was infected. Six children were HCV RNA-positive immediately after birth. Transmission rate was higher (10%) in 20 recipients of blood transfusions (3.3-16.7%) and in 111 women with a history of intravenous drug use (IVDU). In this cohort the transmission rate was 8.1% (5.5-10.7). The transmission rate was lower in 144 women of unknown risk factor: 1.4% (0.4-2.4%). The relative risk of transmission in women of unknown risk of infection was 0.17% as compared to transfused and IVDU women (p=0.00633). HCV genotype was constantly identical within the mother-child pair. As for breast-feeding 6/87 breast fed and 7/188 formula-fed children were infected (p=0.358). Three out of 6 breast-fed infants were already infected in the first day of life, before breast-feeding was started. No difference in maternal viremia was found between infected and uninfected children. This study suggest that 1) only children of HCV-RNA-positive mothers are at risk of infection, 2) in utero HCV trasmission does occur 3) HCV transmission in HIV-1 negative mothers is present, even if low 4) transfused or IVDU are more transmissive than women of unknown risk of infection 5) breast feeding does not seem to represent a risk factor in HCV tranmsmission 6) importance of maternal viremia was not demonstrated.

Clinical, histological, and virological features of hepatitis C virus carriers with persistently normal or abnormal alanine transaminase levels

This study was aimed to evaluate demographic, clinical, histological, and virological characteristics of 46 hepatitis C virus (HCV) carriers with persistently normal alanine transaminase (ALT) levels and to compare the results with those obtained in a group of 52 HCV-RNA-positive patients with elevated ALT levels. Subjects with normal ALT were more often females (P < .001), were more likely to be asymptomatic (P < .001), and have a lower incidence of risk factors for HCV transmission (P < .01). All patients with normal ALT had significant histological liver damage. The mean grading and staging did not differ between patients with normal and those with raised ALT concentrations. Moderate to severe hepatitis was more frequently found among subjects with normal than with elevated ALT. HCV genotype 2a was far more common in subjects with normal (43%) than with abnormal ALT levels (6%; P < .002), genotype 1b being more frequent in these latter (50% vs. 17%; P < .001). Patients with normal ALT levels had similar serum HCV-RNA titers than subjects with raised ALT. Neither HCV genotype distribution nor viral load correlated with the severity of liver damage. We conclude that significant liver disease may occur irrespective of clinical symptoms, ALT levels, HCV genotypes, and viral load. (Hepatology 1997 Dec;26(6):1393-8)

Lymphocyte reactivity to hepatitis C virus (HCV) antigens shows evidence for exposure to HCV in HCV-seronegative spouses of HCV-infected patients.

Lymphocyte reactivity against hepatitis C virus (HCV) antigens was studied in 20 couples in which 1 member had chronic hepatitis C. This was done to investigate the possibility of HCV transmission between spouses that was not followed by seroconversion. Twenty healthy subjects without any risk factors for HCV transmission served as negative controls. All the patients' spouses and the healthy controls were negative for HCV RNA and for anti-HCV antibody. Lymphocytes were cultured with recombinant HCV core and nonstructural antigens (c22, c33, c100, c200, and NS5) and with control antigens (sperm whale myoglobin, chicken lysozyme, and superoxide dismutase). Lymphocytes from 10 patients and 4 seronegative spouses proliferated in the presence of at least one HCV antigen. No proliferation was shown with nonspecific antigens or in the control group. This study gives evidence for possible in vivo priming with HCV antigens that did not lead to seroconversion in spouses of HCV-positive patients.

Phylogenetic tree-based epidemiological analysis of hepatitis C virus transmission in a region of Japan with a high prevalence of infection.

Local clustering of hepatitis C virus (HCV) infection has been demonstrated in various regions in Japan. HCV genotypes have now been compared between infected individuals from districts of Saga prefecture with either a high (H district) or low (L district) prevalence of HCV-seropositivity. The prevalence of HCV genotype 1b was significantly higher (P < 0.001) in the H district (45/50; 90%) than in the L district (19/36; 52.8%). A phylogenetic tree was constructed based on the genomic sequences of viral isolates from 20 patients infected with genotype 1b in the H district. Almost all these HCV strains clustered in the same regions of the tree. With regard to risk factors for HCV transmission, the percentage of patients with a history of surgery was significantly higher in the H district than in the L district (58 versus 33.3%; P < 0.05). Of 20 patients infected with similar strains of HCV in the H district, 16 (80%) had at least one parenteral risk factor associated with medical care. These results indicate an increased transmission of similar strains of HCV in the H district as a result of nosocomial infection.

Hepatitis C virus: epidemiology and genotypes in the north east of England.

The epidemiology of hepatitis C virus (HCV) infection was studied in an English teaching hospital over an 18 month period. A total of 104 HCV antibody positive patients were referred for further investigation. They were divided into those diagnosed through screening (blood donors and intravenous drug abusers) and those diagnosed for other reasons, and their mean ages, known risk factors for HCV transmission, genotypes, and liver biopsy histology were analysed. Screened patients were significantly younger than the others. No significant difference in age was found between genotypes. Most patients genotyped (69%) were genotype 1. Intravenous drug abusers had a higher proportion of subtype 1a, and patients who acquired HCV through blood transfusion had a higher proportion of subtype 1b. Liver biopsy specimens were scored using a histological activity index for liver inflammation and fibrosis. Patients with subtype 1b had significantly more severe liver disease than other genotypes when the histological activity index scores for fibrosis were analysed (p < 0.05). Liver disease worsened significantly with age according to all three histological activity index scores (portal activity: p < 0.01, acinar activity: p < 0.001, fibrosis: p < 0.0001). Liver disease worsened with increased duration of infection (p < 0.002), and patients who also abused alcohol presented at a significantly younger age (cirrhosis, p < 0.05, hepatocellular carcinoma, p < 0.02).

Prevalence of anti-hepatitis C virus antibodies among patients hospitalized in a medical unit

Background: Most cases of hepatitis C virus (HCV) infection are not associated with blood transfusion, and only 50% of the patients have a history of exposure to blood. The role of inapparent sources of infection has yet to be established. Few data exist concerning the prevalence of anti-HCV antibodies among hospitalized patients. Objective: To assess the prevalence of anti-HCV antibodies in a group of 728 consecutive inpatients admitted to a medical unit, and to ascertain whether hospitalization represents a potential risk factor for HCV transmission. Results: Of the patients, 73.3% with and 4.6% without chronic liver disease were found to be anti-HCV-positive. The rate of previous hospital admissions did not differ between anti-HCV-positive and -negative patients. Conclusions: Anti-HCV antibody prevalence among patients admitted to medical units is higher than in the general population; however, hospitalization alone does not seem to place a patient at risk of acquiring HCV infection. Diagnostic procedures, rather than the hospital stay, should be regarded as potential sources of parenteral infection.