Prevalence and role of hepatitis C viraemia in haemodialysis patients in Japan

High false-negative rate of anti-HCV among Egyptian patients on regular hemodialysis

Routine serological testing for hepatitis C virus (HCV) infection among hemodialysis (HD) patients is currently recommended. A dilemma existed on the value of serology because some investigators reported a high rate of false-negative serologic testing. In this study, we aimed to detect the false-negative rate of anti-HCV among Egyptian HD patients. Seventy-eight HD patients, negative for anti-HCV, anti-HIV, and hepatitis B surface antigen, were tested for HCV RNA by reverse transcriptase polymerase chain reaction (RT-PCR). In the next step, the viral load was quantified by real-time PCR in RT-PCR-positive patients. Risk factors for HCV infection, as well as clinical and biochemical indicators of liver disease, were compared between false-negative and true-negative anti-HCV HD patients. The frequency of false-negative anti-HCV was 17.9%. Frequency of blood transfusion, duration of HD, dialysis at multiple centers, and diabetes mellitus were not identified as risk factors for HCV infection. The frequency of false-negative results had a linear relation to the prevalence of HCV infection in the HD units. Timely identification of HCV within dialysis units is needed in order to lower the risk of HCV spread within the HD units. The high false-negative rate of anti-HCV among HD patients in our study justifies testing of a large scale of patients for precious assessment of effectiveness of nucleic acid amplification technology testing in screening HD patient.

[High prevalence and incidence of hepatitis C virus infections among dialysis patients in the East-Centre of Tunisia]

Hemodialysed patients are recognised as a group at increased risk of infection with hepatitis C virus (HCV). The aim of this study was to determine the prevalence and incidence of HCV infection among dialysis patients of the east-centre part of Tunisia. Two hundred and seventy-six patients dialysed until 2001 were recruited within seven hemodialysis units located in the cities of Sousse, Monastir and Mahdia. The serum markers of HCV infection were tested over the period of March 2000-December 2002, by a 3rd generation ELISA test for antibodies and by qualitative RT-PCR technique for viral RNA. The prevalence of anti-HCV antibodies and of HCV RNA was 32.6% (90 patients) and 25.7% (71 patients), respectively. Between 1998 and 2002, 20 new infections were documented in five of the seven dialysis units corresponding to an incidence of 2.34% per year, with an average time of contamination after the beginning of dialysis of 4.6 years. If all the infections are assessed to have occurred during dialysis, the density of incidence of HCV contamination was 4.4% per year of dialysis. A high correlation was noticed between the presence of HCV markers in serum and the duration of dialysis (F = 34.15, P < 0.0001). In the absence of other risk factors (transfusion, drug-addiction), these results plead for the nosocomial transmission of the observed HCV infections. A phylogenetic analysis of the E2 hypervariable region of the viral genome is in progress to confirm this assumption.

Confirmation of nosocomial hepatitis C virus infection in a hemodialysis unit

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

TT-virus infection in Japanese general population and in hemodialysis patients

To determine TT virus (TTV) prevalence and the persistence of viremia, we prospectively did cross-sectional and longitudinal studies using by the polymerase chain reaction to test the successive sera of 150 Japanese hemodialysis patients and compared these with those of 166 residents of a rural Japanese area endemic for hepatitis C virus (HCV). TTV DNA positivity was significantly higher in 50 (30.1%) of the residents than in 25 (16.7%) of the patients in 1997 (P < 0.05). TTV DNA positively in the patients was not associated with HCV RNA positivity and also increased with the number of blood transfusions and decreased with the duration of hemodialysis, but not significantly. Longitudinal study from 1997 to 1999 showed that persistent TTV DNA positivity was found significantly more often in 35 (21.1%) of the residents than in 13 (8.6%) of the patients (P < 0.05), and that persistent TTV DNA negativity was found significantly more often in 103 (68.7%) of the patients than in 91 (54.8%) of the residents (P < 0.05). Of the 25 patients and 50 residents TTV DNA positive in 1997, TTV DNA was eliminated more often in 12 (48.0%) patients than in 15 (30.0%) residents over the three years, but the difference was not significant. The route of TTV transmission might differ from HCV in that it could be nonparenteral. TTV was less prevalent in hemodialysis patients than residents, and the virus was more often eliminated by hemodialysis patients than by residents during the three-year observation period, possibly because of the effect of the hemodialysis procedure.

Acute hepatitis C among Japanese hemodialysis patients: a prospective 9-year study

OBJECTIVES

The aims of this prospective survey were to determine the incidence and clinical characteristics of newly acquired hepatitis C virus (HCV) infection in hemodialysis patients after the start of antibody to HCV (anti-HCV) screening for blood products in Japan in 1989.

METHODS

In serial serum samples from 269 hemodialysis patients who were followed over a mean period of 6.6 yr (+/- 2.1 yr) from 1990 to 1998, HCV RNA and anti-HCV were detected by reverse transcription-polymerase chain reaction and second generation ELISA, respectively.

RESULTS

During the observation period, newly acquired HCV infection was found in 26 (15.4%) of the 169 hemodialysis patients without anti-HCV or HCV RNA at entry, an annual incidence rate of 2.59%. Of these 26, only four had a history of blood transfusion, one of whom had received the blood transfusion after 1992, the year in which screening of blood products for anti-HCV by second-generation ELISA was introduced in Japan. Persistent HCV viremia was found in 17 (65.4%) of the 26 patients; the other nine (34.6%) had transient HCV infection. The mean period of continuous ALT abnormality was significantly longer in the former (12.4+/-13.6 months) than in the latter (1.9+/-3.5 months) (p = 0.0067). However, only three (17.6%) of 17 patients with chronic HCV viremia had continuous ALT abnormality for more than 24 months; in all of them, ALT eventually normalized.

CONCLUSIONS

These findings indicate that newly acquired HCV infection has continued to occur in hemodialysis patients after the initiation of anti-HCV screening of blood products and that the abnormal ALT found in these patients is related to HCV chronicity.

Differences in HCV antibody patterns in haemodialysis patients infected with the same virus isolate

Eight cases of de novo hepatitis C virus (HCV) infection in a haemodialysis unit in Rio de Janeiro, Brazil, were retrospectively studied. HCV viraemia was demonstrated by RT nested PCR in seven of the seroconverters. Genotyping showed that six patients were infected with a genotype 1b strain and one with a genotype 1a strain. A phylogenetic analysis of nucleotide sequences of the HCV core region revealed that five of the six 1b isolates form a separate cluster when compared with other 38 HCV 1b core sequences randomly chosen from the GenBank. The revealed sequence similarities indicated the nosocomial spread of a single HCV strain within the unit. To investigate whether the patients infected with the same viral isolate display similar patterns of antibody response to individual proteins, serial serum samples were examined. A line immunoassay for qualitative and semi-quantitative determination of specific antibodies against recombinant and synthetic HCV antigens was employed. Despite infection with the same virus strain, the patients sera demonstrated different patterns of reactivity against individual structural and nonstructural HCV proteins immediately after seroconversion. For each patient, however, antibody responses remained mostly stable throughout the follow-up of 8 to 24 months.

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.

Maintenance hemodialysis decreases serum hepatitis C virus (HCV) RNA levels in hemodialysis patients with chronic HCV infection

OBJECTIVE

Hepatitis C virus (HCV) infection is a major complication among hemodialysis patients the world over. To determine the natural course of HCV viremic levels in patients on maintenance hemodialysis, we prospectively quantified the HCV RNA levels in serial blood samples from hemodialysis patients and compared them with those in nonuremic subjects.

METHODS

The population studied included 98 hemodialysis patients and 228 nonuremic subjects with chronic HCV infection. HCV RNA was detected by polymerase chain reaction (PCR) and the levels were determined by branched DNA probe assay. HCV RNA genotypes were determined by PCR using type-specific primers.

RESULTS

HCV RNA levels were significantly lower in hemodialysis patients (median, 0.4x10(6) genome equivalent [Meq]/ml) than in nonuremic subjects (median, 3.0 Meq/ml) (p<0.05). HCV of genotype 1b was prevalent in the hemodialysis patients (81.6%) and nonuremic subjects (88.6%). HCV RNA levels in 20 hemodialysis patients with genotype 1b were significantly reduced after each hemodialysis procedure (p<0.05). The 3-yr prospective observation from 1995 to 1998 showed a significant decrease of HCV RNA levels in 47 hemodialysis patients with genotype 1b (median, 1.9-0.9 Meq/ml, p<0.05), whereas levels in 155 nonuremic subjects with genotype 1b did not decrease (median, 2.6-3.0 Meq/ml). There were no patients or nonuremic subjects with undetectable HCV RNA by a PCR assay during the observation period.

CONCLUSIONS

These observations suggest that maintenance hemodialysis decreases the HCV RNA levels in hemodialysis patients with chronic HCV infection, but does not produce clearance of the viremia.

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

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

Blood-borne virus infections in dialysis units--a review

Hepatitis outbreaks in haemodialysis unit patients and staff were reported in the late 1960s. In 1972, the Rosenheim report in the UK established guidelines which included routine tests for hepatitis B surface antigen and isolation facilities for dialysing patients with hepatitis B virus which resulted in a dramatic fall in cases of hepatitis. However, since these guidelines were introduced, other blood-borne viruses, notably HCV and HIV have been discovered, and failures of infection control practices still lead to outbreaks of HBV in haemodialysis units. The prevalence of HCV in dialysis patients varies considerably throughout the world, with reported prevalence ranging from 3.9% to 71%. The number of blood transfusions and the length of time on dialysis have consistently been associated with HCV prevalence. Several reports provide evidence of patient-to-patient HCV transmission with environmental blood contamination the most significant factor in intra-unit transmission. There is no evidence that HCV has been transmitted by re-use of dialysis machines but being dialysed next to an HCV positive patient is associated with a significant risk of HCV acquisition. Several studies have shown that dialysing HCV positive patients in a separate unit or in a defined sector of a dialysis unit significantly reduces nosocomial HCV infection. HGV is prevalent in dialysis units where there is evidence of transmission to patients but no evidence of associated symptoms. HIV is infrequently transmitted in dialysis units and several units treating many HIV-positive patients have shown no evidence of transmission. Careful attention needs to be paid to infection control procedures and regular virological testing.

Hepatitis G virus in the general population and in patients on hemodialysis

To determine the routes of transmission of hepatitis G virus (HGV) and the relationship between HGV and hepatitis C virus (HCV) infections, we tested for HGV RNA by polymerase chain reaction and antibody to HCV (anti-HCV) in 494 hemodialysis patients, 638 inhabitants of two HCV endemic areas, and in 400 blood donors in Japan. HGV RNA was detected in 6.9% of hemodialysis patients, in 1.4% of inhabitants, and in 0.8% of donors, and anti-HCV was detected in 39.3%, 12.4%, and 1.8%, respectively. Of HGV RNA-positive hemodialysis patients, and HGV RNA-positive inhabitants, 64.7% and 11.1%, respectively, had been given blood transfusions. The prevalences of HGV RNA and anti-HCV significantly increased with the duration of hemodialysis. Of all HGV RNA positives, 74.4% were coinfected with HCV and subjects with HGV RNA alone had normal liver function. In conclusion, HGV is transmitted by blood transfusion and within the hemodialysis unit itself. HGV does not seem to injure hepatocytes.

Hepatitis C in dialysis patients

Patients on hemodialysis have a higher prevalence of hepatitis C (HCV) infection compared with the general population. Several factors have been associated with an increased risk of HCV infection in hemodialysis patients, including number of blood transfusions, duration of hemodialysis, previous transplantation, intravenous drug abuse, male gender, and in-center hemodialysis. In addition, there is mounting evidence to suggest nosocomial transmission within hemodialysis units. Although the precise modes of transmission have not been identified, breakdown in standard infection control practices, physical proximity to an infected patient, and sharing of dialysis machines are possible causes. Nonetheless, at the present time, the Centers for disease Control and Prevention (CDC) does not recommend dedicated machines, patient isolation, or a ban on re-use in hemodialysis patients with HCV infection. Consequently, strict adherence to universal precautions and careful attention to hygiene are recommended to reduce the transmission of HCV in dialysis units.

Anti-HCV seroprevalence and risk factors of hepatitis C virus infection in Moroccan population groups

Hepatitis C virus (HCV) seroprevalence and transmission routes were investigated in several groups of the Moroccan population. This study showed a low HCV seroprevalence in the Moroccan general population. However, haemodialysis patients and haemophiliacs were at higher risk of having HCV infection, since the prevalences were, respectively, 35.1 and 42.4% in comparison with the blood donors' prevalence (1.1%). These results indicated that parenteral exposure is the transmission pathway of HCV. To investigate the possibility of vertical HCV transmission, a cohort of healthy, unselected pregnant women were included in the study. A prevalence of 1% was found among them. Seven newborns were anti-HCV-positive, although, when RT-PCR was used to search for HCV RNA in their sera, none of them was viraemic. These data indicated that anti-HCV antibodies were passively acquired in these cases. We concluded that vertical transmission is absent when mothers are at low risk of contracting other parenterally or sexually transmitted diseases. Three percent of a group of patients of a centre for sexually transmitted diseases were repeatedly anti-HCV-positive, suggesting the possible sexual transmission of HCV. When screening 116 sera of anti-HIV-positive subjects, 19.8% were anti-HCV-positive. Furthermore, 17.9% of the sixty-seven patients who were proven to have sexually contracted HIV were also anti-HCV-positive. These data might reflect a likely cotransmission of these two viruses, hence suggesting HIV is a cofacter for HCV sexual transmission, as previously reported.

Inverse correlation between the titre of antibody to hepatitis C virus and the degree of hepatitis C viraemia

We titrated 277 hepatitis C virus (HCV) antibody-positive serum samples from 235 volunteer blood donors as well as from 42 outpatients of a hospital for elderly people and studied the relation of the titre of HCV antibody to the presence of HCV RNA, of antibody to C100 protein (anti-c100) and of antibody to GOR epitope (anti-GOR). Liver dysfunction was measured also. Of 177 HCV RNA-positive serum samples, 87 were tested for the degree of HCV viraemia by means of a competitive assay. Among the 277 samples, prevalences of HCV RNA, anti-c100, anti-GOR and liver dysfunction were 63.9%, 71.8%, 75.7% and 17.5%, respectively. The prevalence of HCV RNA became higher as the titre of HCV antibody increased. The titre tended to increase with age but the tendency was not statistically significant. The mean titre was higher in females (2(10.4 +/- 1.8)) than in males (2(9.4 +/- 2.2)) (P < 0.01). In the HCV RNA-positive serum samples, the HCV antibody titre was significantly higher in the anti-c100-positive samples than in the negative ones. This difference between the positive and negative samples, however, was not statistically significant for anti-GOR and liver dysfunction. Low degrees of HCV viraemia were accompanied by high titres of HCV antibody while high degrees of HCV viraemia went with low titres of HCV antibody. The study revealed that titres of HCV antibody were higher in females and the degree of HCV viraemia correlated inversely with the titre of HCV antibody.