Prevalence of false-positive hepatitis C antibody results,National Health and Nutrition Examination Study (NHANES) 2007–2012

BackgroundScreening large numbers of persons in a population with low prevalence of a disease leads to many false-positives. However, populations with low HCV prevalence may sometimes be recommended for HCV screening, for instance patients or healthcare workers after a possible healthcare-related exposure.ObjectivesWe determined the percentage of true vs false-positive HCV antibody (anti-HCV) test results among 2007–2012 participants in the National Health and Nutrition Examination Study (NHANES), a nationally representative study with approximately 1% HCV infection prevalence, much lower than in groups typically recommended for HCV screening.Study designAnti-HCV test confirmation was performed using a recombinant immunoblot assay (RIBA) test and follow-up HCV RNA testing.ResultsOverall, of 22,359 NHANES participants tested, 479 (2%) were anti-HCV screening reactive and 477 were tested for RIBA; of these 323 (68%) confirmed as true positive and 105 (22%) were false-positives. Many others (49, 10%) were RIBA indeterminate and likely false-positive. Because of these false positive tests, the overall prevalence of chronic infection among those testing anti-HCV screening reactive was much lower (218, 51%) than would be expected due to disease clearance alone (approximately 80%).ConclusionsAll screening anti-HCV positive tests should be followed by an HCV RNA test, in order to confirm whether the patient has current infection so that infected persons can be referred to care and treatment to avoid the significant morbidity and mortality associated with chronic HCV infection.     

Hepatitis virus infection among hemodialysis patients

AIM, PATIENTS AND METHODS: The high prevalence of anti-hepatitis C virus antibodies (anti-HCV) in hemodialyzed (HD) patients has been recognized since the early 1990s. Over the last decade, a significant decrease of anti-HCV prevalence among HD patients has been observed in many west European countries. In order to evaluate whether this trend is also present in Dialysis Center of Dubrava University Hospital, Zagreb, we tested HD patients for anti-HCV and HCV RNA in serum. ELISA 3 (Sorin) was used as a screening anti-HCV test, and confirmatory testing relied on western blotting (BioRad). HCV RNA was tested by HCV RNA PCR (Roche) and AMPLICOR, HCV test, version 2.0 (Roche). RESULTS AND DISCUSSION: The low prevalence of HCV infection is a consequence of the screening of blood donors with increasingly sensitive anti-HCV tests, followed by the progressive reduction of blood transfusion due to the availability of erythropoietin and the reinforcement of universral hygienic precautions and strict infection control in our HD unit. A contributing factor was the prevention of nosocomial transmission by the separation of anti-HCV positive from anti-HCV negative patients. Thus, the low prevalence of HCV infection in our HD center contributes-to an improved prognosis in end stage renal disease patients by additionally reducing the risk of nosocomial HCV infection.     

Hepatitis C virus antibodies among risk groups in a South African area endemic for hepatitis B virus

The prevalence of anti-HCV was studied in a South African area endemic for hepatitis B virus. A total of 35,685 volunteer blood donors (22,034 whites, 9,218 Asians, 3,077 Africans, 1,356 coloureds), 71 haemophiliacs, 84 chronic dialysis patients, 100 antenatal attenders, 212 nurses, and 20 HIV-positive male homosexuals were tested for anti-HCV. Repeat positive second generation Ortho HCV EIA was used to determine HCV status for the blood donors; Abbott-II HCV EIA combined with a neutralisation test was used for the other risk groups. Antibody to hepatitis B core antigen (anti-HBc) was also tested in the haemophiliacs, nurses, and chronic dialysis patients. Seroprevalence for the blood donor population was 0.16, 0.34, 0.75, and 0.22% for whites, Asians, Africans, and coloureds, respectively. Of the risk groups tested, 39.4% of haemophiliacs and 4.8% of chronic dialysis patients were positive; of the remainder tested none was positive. Fifty percent of nurses, 47.9% of haemophiliacs, and 22.6% of dialysis patients had serological evidence of past exposure to hepatitis B virus (anti-HBc positive). These findings indicate a low prevalence of anti-HCV in the blood donor population, thus probably resulting in a low prevalence in groups exposed to blood and blood derivatives. The overall difference in prevalence between the race groups was significant (P < 0.0001). The high prevalence of hepatitis B virus compared to the low prevalence of HCV suggests that the main modes of transmission of the two viruses are probably different. © 1993 Wiley-Liss, Inc.     

Hepatitis C virus infection and diabetes mellitus in end-stage renal disease: evidence of a negative association

Epidemiological studies have implicated hepatitis C virus (HCV) infection in the pathogenesis of diabetes mellitus (DM) both in the population as a whole and after solid organ transplantation. Whether this association exists in patients with end-stage renal disease (ESRD) undergoing dialysis is unclear. The aim of this study is to investigate the relationship between HCV and DM in a large group (n=742) of patients with ESRD from Europe and North America. The presence of diabetes was ascertained by using American Diabetes Association guidelines based on fasting glucose measurement and medication history. Presence of HCV infection was assessed by serum testing for anti-HCV antibodies. The prevalence of anti-HCV antibody positive patients was 15% (112/742); the frequency of DM was higher among anti-HCV positive than -HCV negative patients but the difference did not approach statistical significance, 32% (36/112) vs 29.5% (186/630). The frequency of patients with diabetic nephropathy was not higher in anti-HCV positive than -negative patients; 21.4% (24/112) vs 23.3% (147/630), NS. Logistic regression model showed an independent and significant link between anti-HCV seropositive status and raised GPT (P=0.032), male gender (P = 0.0462), positive history of prior renal transplant (P=0.0006), and longer time on dialysis (P=0.00001). In summary, no link between anti-HCV antibody and DM occurred in this ESRD population; there was no association between rate of anti-HCV antibody and diabetic nephropathy.     

Hepatitis C virus in sickle cell disease

PURPOSE: To determine the prevalence of hepatitis C virus antibodies (anti-HCV) in patients with sickle cell disease. PATIENTS AND METHODS: Between 1983 and 2001, 150 patients from the Howard University Hospital Center for Sickle Cell Disease were screened for HCV antibody (52% women, 48% men, mean age 34 years). Frozen serum samples from 56 adult sickle cell patients who had participated in previous surveys (1983-92) of HIV and HTLV-1 serology and who were tested in 1992 for anti-HCV antibody--when commercial ELISA test (Ortho) became available--were included in this paper. Of the 150 patients in the study, 132 had sickle cell anemia genotype (SS), 15 had sickle cell hemoglobin-C disease (SC) and three had sickle beta thalassemia. Clinical charts were reviewed for history of blood transfusion, IV drug abuse, homosexuality, tattooing, iron overload, and alcohol abuse. RESULTS: Antibodies to HCV were detected in 53 patients (35.3%). Of the 55 patients who had frozen serum samples tested in 1992, 32 (58%) were reactive for anti-HCV, while only 21 of the 95 patients (22%) tested after 1992 were positive for HCV antibodies (P<0.001). Thirty-nine of 77 patients (51%) who received more than 10 units of packed red blood cells were positive for HCV antibody, and only 14 of 61 patients (23%) who received less than 10 units of packed red blood cells transfusion were positive for HCV antibodies (P<0.001). None of the 12 patients who never received transfusion were positive for HCV antibody. In the 53 anti-HCV positive patients, the mean alanine amino-transferase (ALT) value was 98- and 81 U/L, respectively, for males and females. These values were normal for the HCV-antibody negative patients. The aspartate amino-transferase (AST) and the total bilirubin were also higher in the anti-HCV positive patients compared to patients in the anti-HCV negative group. Forty-four patients (57.1%) who were transfused more than 10 units developed iron overload defined by a serum ferritin level higher than 1,000 ng/ml. A total of 20 of the patients with iron overload underwent liver biopsies. Seven of these 20 patients (35%) were HCV positive. These patients often had more severe liver disease and higher degree of iron deposition. CONCLUSION: The prevalence of HCV antibody and iron overload is directly related to the number of blood transfusions in patients with sickle cell disease. The prevalence of HCV infection has decreased significantly, since blood donor screening for HCV became available. Chronic HCV infection and iron overload place sickle cell patients at risk for significant liver disease.     

The detection of hepatitis C virus in South Hungary.

BACKGROUND: 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. OBJECTIVES: 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. STUDY DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.     

慢性丙型肝炎与Ⅱ型糖尿病关系的研究

目的：探讨慢性丙型肝炎病毒（HCV）感染与Ⅱ型糖尿病发病的关系。方法：①对227例慢性乙型肝炎（乙型肝炎后肝硬化86例）与126例慢性丙型肝炎患者（丙型肝炎后肝硬化30例）进行病例分析研究，明确其是否合并糖尿病。②用ELISA方法对160例Ⅱ型糖尿病患者及223例体检人群进行抗HCV、HBsAg检测。结果：①126例慢性丙型肝炎患者合并Ⅱ型糖尿病24例（19．05％），227例慢性乙型肝炎患者合并Ⅱ型糖尿病19例（8．37％），二者比较差异有显著性（P＜0．01），年龄及丙型肝炎为发生糖尿病的独立危险因素。②160例Ⅱ型糖尿病患者中抗HCV阳性5例（3．12％），HBsAg阳性7例（4．37％），223例体检人群抗HCV阳性0例，与糖尿病人群差异有显著性（P＜0．05），HBsAg阳性12例（5．38％），与糖尿病人群差异无显著性（P＞0．05）。结论：①慢性丙型肝炎病毒感染易合并Ⅱ型糖尿病。②Ⅱ型糖尿病患者中丙型肝炎感染率高于普通人群，提示HCV感染与糖尿病的发生有一定关系，HCV感染可能为Ⅱ型糖尿病发病因素之一。     

游离丙型肝炎病毒核心抗原检测的临床价值探讨

目的:探讨游离丙型肝炎病毒(HCV)核心抗原检测在HCV感染诊断中的价值。方法:采用荧光定量PCR法检测HCV-RNA、ELISA法同步检测抗-HCV和游离HCV核心抗原。结果:191例HCV感染者HCV-RNA的检出率为71·2%(136/191);抗-HCV的检出率为97·4%(186/191);游离HCV核心抗原的检出率为33·0%(63/191)。其中有2例经抗病毒治疗的患者HCV-RNA和抗-HCV检测均阴性,但游离HCV核心抗原检测阳性;另有1例患者抗-HCV阴性,而游离HCV核心抗原阳性,经HCV-RNA证实为HCV感染。27例非HCV感染者HCV-RNA、抗-HCV和游离HCV核心抗原检测结果均为阴性。结论:HCV核心抗原检测作为抗-HCV检验的补充试验对HCV感染的诊断具有重要价值。     

Hepatitis C virus infection in hemodialysis patients in southern Sweden: Epidemiological,clinical, and diagnostic aspects

A prevalence of hepatitis C virus (HCV) antibodies of 12% was found in 276 patients from 11 dialysis units. Between zero and 22% of the patients in the different units were anti-HCV positive. The epidemiology of HCV was studied in two units during a 2 year period by antibody assays and the polymerase chain reaction and correlated with clinical manifestations. Two types of epidemiologic patterns were found that may explain the wide difference of HCV prevalence described in different dialysis units. In one unit there was no evidence of spread within the unit, and the prevalence of HCV was dependent on the status of the patients entering for treatment. In the other unit, a clustering of infected patients could be seen in which 13 of 36 were infected during a 3 year period. Some patients who had not received blood transfusions were among the infected. Hepatitis C infection was the most common explanation for repeated abnormal transferase levels. Most of the HCV-infected patients reacted both for anti-HCV and HCV RNA. HCV RNA was in general detected earlier than anti-HCV seroconversion. Among 20 HCV RNApositive serum samples that were anti-HCV ELISA-positive 18 had indeterminate and two negative reactions by immunoblot (RIBA 2). Thus the RIBA 2 test should be used with caution as a confirmatory antibody test in this group of patients. © 1993 Wiley-Liss, Inc.     

Prevalence and significance of antibodies to hepatitis C virus among Saudi haemodialysis patients.

Seventy-four patients who were maintained on chronic haemodialysis in King Khalid University Hospital, Riyadh, Saudi Arabia were tested using the recently available ELISA to determine the prevalence of antibodies to hepatitis C virus (anti-HCV) in a haemodialysis unit. The prevalence rate of anti-HCV antibodies of 41.9% in the haemodialysis patients was significantly higher than the rate of 3.9% detected in 488 asymptomatic blood donors who were similarly tested. In the haemodialysis patients, anti-HCV positivity was related to previous blood transfusion (greater than 5 units of blood) and to the duration of haemodialysis (greater than 4 years); but was unrelated to sex, age, positive HBV markers or to past or current elevation of serum ALT. The results indicate a relatively higher prevalence of anti-HCV antibodies in our patients compared to rates of 1-20% reported from Europe and the U.S.A. An effective control strategy for HCV infection in this high risk group is urgently indicated.     

Hepatitis C virus infection among pregnant women in Yaounde,Cameroon: prevalence,viremia, and genotypes

Central Africa is considered to be an area of high endemic hepatitis C infection. To determine the prevalence of anti-HCV antibodies, HCV RNA, and the genotype distribution in Cameroon, 1,494 pregnant women attending antenatal care units in Yaounde, Cameroon were screened for HCV infection. Anti-HCV antibodies were detected with a 3rd generation ELISA (Monolisa anti-HCV plus version 2, BioRad, Richmond, CA). All anti-HCV antibody-positive sera were then tested with another 3rd generation ELISA (AxSYM) HCV version 3, Abbott Laboratories, Abbott Park, IL) and subsequently for HCV RNA (Amplicor HCV, Roche Diagnostics, Basel, Switzerland). Genotype was determined by phylogenetic analysis of the NS5b gene. Seventy-three pregnant women were found to be anti-HCV antibody positive by the first ELISA, but only 28 were anti-HCV positive by both ELISA. The prevalence of anti-HCV antibodies was thus 1.9% (28/1,494) (95% CI: 1.3-2.7%). 21/28 (75%) of the positive samples by both ELISA were HCV RNA positive. The 45 samples that were HCV antibody negative by the second ELISA were also HCV RNA negative. The HCV subtypes identified were 1a (24%), 2f (38%) and 4f (38%). In contrast to previous studies, anti-HCV antibodies were rare among pregnant women in Cameroon. The percentage of HCV seropositive pregnant women who had circulating HCV RNA was similar to that observed in Europe. Several HCV genotypes were found in Cameroon.     

Hepatitis C infection and viremia in Dutch Hemophilia patients

Serum samples from 316 patients visiting the Dutch National Hemophilia Center were collected from 1979 to 1993 and stored at ?30°C. Patients were placed into three different groups: (1) patients ever treated with large pool non-hepatitis C virus (HCV)-safe concentrate (n=179); (2) patients treated with cryoprecipitate (n = 125); and (3) patients treated exclusively with HCV-save concentrate (n=12). In order to examine the prevalence of HCV infection in the different treatment groups serum samples were tested retrospectively for anti-HCV antibody using second generation enzyme-linked immunosorbent assay (ELISA) and recombinant immunoblot assay (RIBA-2). Significant differences in the prevalence of HCV infection were found between these 3 groups (group 1: 99%, group 2: 66%, group 3: 0%). The safety of currently administered clotting products is demonstrated in 57 patients who remained without HCV markers between 1989 and 1993. To examine the natural course of HCV infection fresh-frozen plasma samples were obtained recently from a subgroup of 277 hemophilia patients for HCV-RNA detection by a well-validated cDNA-PCR assay. In contrast to other reports, no evidence was found for seronegative HCV carriers. None of 52 patients without anti-HCV had detectable HCV-RNA. Of 225 patients with anti-HCV, 182 (81%) were HCV-RNA positive. None of 39 anti-HCV positive patients with a negative HCV-RNA reaction had serum alanine aminotransferase (ALT) levels above 50 U/l, whereas 44% of HCV-RNA positive patients had persistently elevated ALT levels above 50 U/l. These results indicate that 20% of hemophilia patients who have been infected with HCV in the past eliminated the virus or have viral replication below the detection limit of polymerase chain reaction (PCR) without biochemical evidence of liver damage. © 1995 Wiley-Liss, inc.     

Prevalence of hepatitis C virus antibodies among patients infected with human immunodeficiency virus.

A study was undertaken to determine the prevalence and risk factors for serological evidence of hepatitis C virus (HCV) infection in patients infected with the human immunodeficiency virus (HIV). Tests for anti-HCV antibody were carried out by enzyme-linked immunoassay (EIA) on 101 HIV-infected patients from two university-based outpatient clinics. Anti-HCV antibody reactive samples were tested by using a recombinant immunoblot assay (RIBA) for HCV antibodies. Fourteen of 101 (13.9%) HIV-infected patients were anti-HCV reactive by EIA. Of these 14, only seven were reactive by RIBA: four were intravenous drug users as a sole risk factor for HIV infection; and the remaining three acquired HIV by blood transfusion, contaminated instrument exposure or IV drug use and sexual contact. Acquisition of HIV by sexual activity alone was not associated with HCV infection. It is concluded that HCV infection is found in approximately 7% of a university HIV clinic population. False-positive anti-HCV antibody serology may lead to overestimation of the prevalence of HCV infection. Female sex and intravenous drug use are significantly associated with HCV infection among HIV-infected individuals.     

Molecular and epidemiological study on nosocomial transmission of HCV in hemodialysis patients in Brazil

An epidemiological and molecular study of hepatitis C virus (HCV) infection was carried out in Brazilian hemodialysis centers. A total of 1,095 patients in all 15 hemodialysis centers in the State of Goiás, Brazil, were studied. All patients were interviewed for possible risk factors to HCV infection and serum samples tested for anti-HCV by ELISA and for HCV RNA by nested RT-PCR of the 5' NC region. For sequence analysis, HCV RNA amplification for the NS5B region (nt 8,279-8,619) was performed. The phylogenetic tree was generated with MrBayes, and clusters with support values above 0.85 were considered epidemiologically related. Of the 1,095 patients, 180 were anti-HCV and/or HCV RNA positive, resulting in an overall prevalence of 16.4% (95% CI: 14.3-18.7). The prevalence of HCV infection in the dialysis centers ranged from 0% to 47.7%. Multivariate analysis of risk factors revealed that history of blood transfusion not screened for anti-HCV and length of time on hemodialysis were independently associated with HCV infection in this population. One hundred six samples could be amplified and sequenced in the NS5B region. Among them, plylogenetic tree analysis revealed that 69 sequences form 13 separated clusters, which were supported by credibility intervals ranging from 85% to 100%, indicating a very close relationship among the HCV isolates and therefore a likely transmission of the virus between patients. By combining phylogenetic analysis with epidemiological data, routes of transmission between the clustered-related-patients could be suggested. These findings provide evidence for nosocomial transmission of HCV in Brazilian hemodialysis centers.     

Detection of hepatitis C virus sequences in sera with controversial serology by nested polymerase chain reaction.

The specificity of first-generation enzyme-linked immunosorbent assays (ELIAs) for antibody detection in individuals with hepatitis C virus (HCV) infection has been questioned in some pathological situations. We observed a surprisingly high prevalence of anti-HCV antibodies in alcoholic patients, and thus, false-positive reactions in anti-HCV tests were strongly suspected. The introduction of new epitopes, particularly a core protein, C22 (second-generation tests), seems to increase the sensitivity of anti-HCV detection. In order to study the specificity of the second-generation tests, 60 serum samples from alcoholic patients found to be positive by the first-generation anti-HCV ELISA (Ortho) were reexamined by a second-generation anti-HCV enzyme immunoassay (Abbott) and a recombinant immunoblot assay (RIBA II; Chiron). Fifteen serum samples gave contradictory results when they were tested by the two assays. We performed nested polymerase chain reactions (PCRs) to confirm that the discrepancies that we observed could be due to the presence of low levels of anti-HCV antibodies, which were detected by a more sensitive test, or to unspecific positive reactions. Nested PCR revealed the presence of HCV RNA sequences in all anti-HCV-positive sera or sera that were weakly positive by ELISA. Anti-HCV positive by RIBA II was always correlated with the presence of viral RNA in serum, but HCV RNA was detected in RIBA II-negative sera. These results indicate that the specificity of the second-generation tests is an important improvement but that an HCV infection can still persist without detectable antibodies. PCR remains the reference assay to clear up controversial serology results and to detect HCV infection in patients with no anti-HCV-detectable immune response.     

Significance of indeterminate third-generation hepatitis C virus recombinant immunoblot assay.

Indeterminate hepatitis C virus (HCV) third-generation recombinant immunoblot assay (RIBA3.0; Ortho Diagnostic Systems) patterns were arbitrarily defined by the manufacturer as the detection of only one antibody out of the four that were sought, namely, c100 (NS4 encoded), c22 (core encoded), c33c (NS3 encoded), and NS5 (NS5 encoded). The aims of the present study were (i) to determine the prevalence of indeterminate RIBA3.0 patterns in patients consecutively tested for anti-HCV antibodies in a university hospital; (ii) to evaluate the significance of these patterns in terms of viral replication, liver disease, and risk factors for HCV; and (iii) to get an insight into the mechanism underlying this peculiar immune response. Among 3,074 serum samples consecutively tested for anti-HCV antibodies, 588 were found to be positive by screening assays. Fifty-nine of them (10%) were RIBA3.0 indeterminate and were compared with 59 RIBA3.0-positive ones. Thirty-one RIBA3.0-indeterminate and 53 RIBA3.0-positive serum samples were HCV RNA positive by PCR (53 versus 90%; P < 10(-6). RIBA3.0-indeterminate and RIBA-3.0-positive patients with positive PCR results were not significantly different for the prevalence of risk factors for HCV infection and elevated serum alanine aminotransferase activities. Immunosuppression, attributable to coexisting human immunodeficiency virus infection, organ transplantation, or the administration of immunosuppressive drugs, was significantly more frequent in PCR-positive, RIBA3.0-indeterminate patients than in PCR-negative, RIBA3.0 indeterminate patients (P < 0.001) and PCR-positive patients with a positive RIBA3.0 result (P < 0.01). The distribution of HCV genotypes did not differ significantly between HCV RNA-positive patients with indeterminate or positive RIBA3.0 results. In conclusion, the prevalence of indeterminate RIBA3.0 patterns in virology laboratories is about 10%; in about half of these patients HCV replication is detected by PCR; the main factor responsible for indeterminate RIBA3.0 patterns could be immunosuppression, whereas HCV genotypes do not seem to play major role.     

Molecular epidemiology of a hepatitis C virus outbreak in a hemodialysis unit in Italy

Hemodialysis patients are at increased risk of hepatitis C virus (HCV) infection. The aim of this study was to investigate a HCV outbreak in a hemodialysis unit using epidemiological and molecular methods. Between April 2003 and October 2003, anti-HCV seronconversion was detected in four patients attending the unit. These cases were added to 10 patients already anti-HCV positive upon admission in the unit. All 14 anti-HCV patients were tested for HCV RNA and HCV genotype. NS5B and HVR1/ E2 genomic regions were amplified and sequenced in all HCV RNA positive patients and phylogenetic analysis was performed. Furthermore, clinical-epidemiological records obtained from all patients were examined. All four patients newly infected harbored genotype 2c. Genotype 2c was also detected in 2 of 10 patients already anti-HCV positive upon admission. Phylogenetic analysis showed that all newly HCV infected patients harbored very closely related viral isolates that clustered together with the 2c isolate found in one of the two 2c chronic infected patients. All HCV-2c infected patients had no other risk factors except hemodialysis. Three of four newly HCV-2c infected patients and the one HCV-2c chronically infected involved in the outbreak received dialysis on the same day and same shift but used different machines. The remaining HCV-2c newly infected patient and one of the above cited three received dialysis on the same day during different shifts but used the same machine. The outbreak was probably due to breaks of infection control procedures although a related-machine transmission cannot be excluded in one of the cases.     

Detection of hepatitis C virus-RNA by polymerase chain reaction in dental surgeries

The mean prevalence of anti-hepatitis C virus (HCV) in Italy is 0.87%. It reaches 2% in Campania, Southern Italy. Approximately 50% of community acquired non-A, non-B (NANB) hepatitis cannot be associated with known parenteral exposure. A recent Italian study has shown that the only demonstrable risk factor in 9% of acute C/NANB hepatitis is dental treatment. There are no data on direct contamination by HCV of dental surgeries. Possible environmental contamination by HCV-RNA was investigated in dental surgeries after treatment of anti-HCV and HCV-RNA positive patients. Thirty-five anti-HCV and HCV-RNA positive patients with chronic hepatitis underwent dental treatment and were enrolled in this study. Eight had chronic persistent hepatitis (CPH), 23 chronic active hepatitis (CAH), and 4 cirrhosis. A total of 328 samples collected from instruments and surfaces were tested after dental treatment of 35 anti-HCV positive patients. The presence of HCV-RNA was determined by polymerase chain reaction (PCR) to evaluate contamination of instruments and surfaces in dental surgeries. Twenty (6.1%) out of 328 collected samples were positive for HCV-RNA. The positive samples were from work benches (two), air turbine handpieces (one), holders (four), suction units (one), forceps (four), dental mirrors (two), and burs (six) Our data indicate that there is extensive contamination by HCV of dental surgeries after treatment of anti-HCV patients and that if sterilisation and disinfection are inadequate there is the possible risk of transmission to susceptible individuals. © 1995 Wiley-Liss, Inc.     

Community prevalence of hepatitis C viraemia: A polymerase chain reaction study

In order to estimate the prevalence of HCV carriage in an inner city health district, we undertook a polymerase chain reaction (PCR) based survey of sera collected from 1,002 patients attending general practitioners for reasons unrelated to liver disease. The series comprised 305 sample selected sera patients sample from sera 995 patients previously screened by C100 antigen-based anti-HCV tests. Overall, 7 patients were positive for HCV RNA. Four cases had anti-C100 antibodies to HCV, 2 were strictly negative but had high-normal/borderline optical densities by ELISA assay, while one was completely anti-HCV negative. All but one had normal liver function tests. Only 3/7 PCR positive cases had any serum marker for hepatitis B (HBV) exposure (2 HBsAg positive, 1 IgM anti-HBc positive). The minimum point prevalence of HCV carriage in this community is 0.7%, approximating the HBsAg carriage in the same population (1%). HCV carriage in this inner city population is considerably higher than would be predicted by blood donor surveys. A positive anti-HCV antibody (anti-C100) test is poorly predictive (～10%) of HCV RNA carriage in a general practice based population in which measurement of “surrogate” (HBV related) HCV markers would have detected only 3/7 cases of presumed chronic HCV carriage. © 1994 Wiley-Liss, Inc.