Determining the source of nosocomial transmission in hemodialysis units in Tunisia by sequencing NS5B and E2 sequences of HCV

Hepatitis C virus infection is a significant problem in hemodialysis units. HCV is very variable genetically with six genotypes. Clinical and epidemiological investigation of a new infection requires the determination of both the genotype and the strain of the HCV involved. A prospective, epidemiologic study of 395 dialysis patients in Tunisia was conducted from November 2001 to November 2003 to identify the source of nosocomial transmission using phylogenetic analysis of NS5b and E2 sequences. Hepatitis C infection was diagnosed by screening for anti-HCV antibodies and HCV RNA in sera using third generation ELISA and a qualitative RT-PCR assay. HCV strains were genotyped by sequencing the NS5b region. The genetic relatedness of the HCV strains was studied by sequencing the NS5b and the HVR-1 regions of the HCV genome. Two de novo cases of HCV infection were detected during the follow-up. One of them has been described previously. The case described in this study occurred in a center in which 12 patients were already infected with HCV strains belonging to genotypes 1b (n = 8) and 1a (n = 4). Phylogenetic analysis of the NS5b region from the HCV strains circulating in this center disclosed four clusters, confirmed by analysis of the HVR-1 region, providing strong evidence for nosocomial infection. Epidemiological data showed that these patients were dialyzed during the same shift and in the same area. Phylogenetic analysis of NS5b sequences is useful for determining the HCV genotype and providing evidence of nosocomial transmission.     

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.     

Vertical transmission of the hepatitis C virus to infants of anti-human immunodeficiency virus-negative mothers: molecular evolution of hypervariable region 1 in prenatal and perinatal or postnatal infections

In a prospective study of 33 infants born to hepatitis C virus (HCV)-positive human immunodeficiency virus-negative mothers the vertical transmission of HCV occurred in 6.8%. The evolution of HCV infection in two babies was studied from birth up to 5 or 6 years of age, and the sequencing of the hypervariable region (HVR) of the putative envelope-encoding E2 region of the HCV genome was performed. The HVR1 sequence variability and the different serological profiles during follow-up could reflect the differences in HCV transmission routes, HCV genotypes, and clinical evolution of infection.     

Hepatitis-C prevalence in an urban native-American clinic: a prospective screening study

BACKGROUND: Native-American populations are disproportionately burdened by chronic liver disease, and the prevalence of hepatitis C (HCV) in native Americans is unknown. PURPOSE: To determine the prevalence of hepatitis C in a local native-American population via a prospective screening study. PROCEDURES: Two-hundred-forty-three native Americans (161 females/82 males) using an urban clinic and representing > 30 tribes from across the United States were screened. Mean age was 41 +/- 1 years. Hepatitis-C screening was by anti-HCV with confirmation by HCV RNA. A questionnaire assessed potential risk factors for HCV. FINDINGS: Anti-HCV antibodies were found in 11.5% (95% CI: 7.5-15.5%). HCV RNA was present by polymerase chain reaction (PCR) in 8.6% (95% CI: 5.1-12.1%) and was more common in males [13.4% (95% CI: 6.0-20.8%)] than females [6.2% (95% CI: 2.5-9.9%)]. The most common potential risk factors for chronic HCV infection were intravenous (IV) drug or cocaine use (p < 0.0001), tattoos > 5 years old (p < 0.0001) and having a sexual partner with HCV (p = 0.0063). CONCLUSION: HCV prevalence is higher in an urban native-American clinic population than reported in the general U.S. population. Use of IV drugs is the most prevalent risk factor, but tattoos and sexual transmission may also be important.     

Serological study of hantavirus in man in the Autonomous Community of Madrid,Spain

Data relating to hantavirus infection in Spain are scarce and limited to rural areas. The aim of this work was to study the seroprevalence of hantavirus infection in the Autonomous Community of Madrid (ACM), a region containing both rural and urban populations in different ecological settings. Sera from 3852 individuals (1849 male, 2003 female) were screened by indirect inmunofluorescence, with Vero E6 cells infected with Puumala, Hantaan and Seoul viruses as antigens. Screen-positive results were confirmed by Western blot with recombinant Seoul virus nucleocapsid protein as antigen. Antibodies against hantavirus were detected in 12 sera (0.31%). No statistical differences were found according to sex and age. The highest prevalence was found in the southeastern area, significantly higher than the central and north-western areas. The most frequent serological pattern was reactivity against all three viruses used (33.3% of all positive sera). Therefore, this study confirms the presence of hantavirus infection in the ACM, including for the first time an urban area of Spain, but with the highest prevalence in a rural area. Serological evidence suggests that there is more than one circulating serotype.     

Community-based seroepidemiological survey of HCV infection in Catalonia, Spain.

The objective of this study was to investigate the prevalence of antibodies against the hepatitis C virus (anti-HCV) and the associated risk factors in a representative sample of the population of Catalonia, Spain. Serum samples from 2,142 subjects aged between 5 and 70 years, selected at random from urban and rural habitats, were studied. Multiple logistic regression analysis was carried out to determine variables associated independently with the presence of HCV antibodies. The age and gender standardized prevalence of anti-HCV was 2.5% (95% confidence interval, 1.8-3.2). Prevalence increased significantly with age (P < 0.001), but no other sociodemographic variables were associated with HCV infection. Tattoos (OR: 6.2), blood transfusions (OR: 5.0) intravenous drug use (OR: 4.9) and antecedents of hospitalization (OR: 2.3) were variables associated independently with infection. HCV infection affects mainly elderly people in Spain and spares children and adolescents. This suggests that major exposure to HCV may have occurred many years ago, when infection was more widespread than in recent years.     

Hepatitis C virus infection and genotypes among human immunodeficiency virus high-risk groups in Cameroon.

Parenteral transmission of HCV is well established but other possible routes such as heterosexual transmission are still questioned. The Central African region is characterised by a high HCV endemicity without any evidence on the route of transmission. The information on HCV genotypes that circulate in this area is also limited and controversial. HIV infection is very frequent in this region and mostly acquired via the heterosexual route. The aim of this work was to investigate the trend of HCV infection and genotypes among HIV high-risk groups from Cameroon. Four hundred eighty-two patients including 229 tuberculosis clinic attendants, 184 sexually transmitted disease clinic attendants, and 69 HIV clinical suspects from another clinic were enrolled. All plasma samples were screened for antibodies to HCV and HCV RNA. Genotypes were assigned by sequencing a 5'UTR amplified fragment. The overall prevalence of HCV markers was 11.6% and a significant increasing trend with respect to age was observed. A proportion of 64.1% (34/53) of HCV antibody positive samples was viraemic. HCV RNA was found in 3 samples that were indeterminate in RIBA 3.0. One was negative in the antibody screening test and the two others were weakly positive. The data on HCV genotypes revealed that genotype 1 was involved in 57% of viraemias, genotype 2 in 24%, while genotypes 4 and 5a accounted for 16 and 3%, respectively. In contrary to the predominance of genotype 4 reported in some African countries and even the neighbouring countries, these data demonstrate clearly that HCV infection in Cameroon is dominated by genotypes 1 and 2. No association was found between the HCV markers and the presence of HIV infection. It is concluded, therefore, that the heterosexual route plays a minor role in HCV transmission in this country.     

Hepatitis C virus infection among dialysis patients in Tunisia: incidence and molecular evidence for nosocomial transmission

In order to study the incidence of hepatitis C virus (HCV) infection in Tunisian haemodialysis patients and detect its nosocomial transmission, 395 patients were enrolled in a prospective study (November 2001-2003). HCV serological and virological status was determined initially using, respectively a third generation ELISA and an RT-PCR qualitative assay. The genotype of the HCV isolates was determined by sequencing NS5B region. The issue of nosocomial transmission was addressed by sequencing the HVR-1 region of the E2 gene. About 20% of the patients had anti-HCV antibodies and HCV-RNA was detected in 73% of the anti-HCV positive patients. Two cases of de novo HCV infection were identified in two dialysis centers, during virological follow-up of patients susceptible to HCV infection. The incidence of de novo HCV infection was 0.5%. Determining the genotypes in the first center disclosed that all HCV-positive patients were infected with genotype 1b; sequencing of the HVR-1 region of the E2 gene provided strong evidence that the isolate from the newly infected patient and another infected dialysis patient were closely related, confirming nosocomial contamination. The investigation of the second center is pending. Besides, one patient with negative HCV serology had detectable HCV-RNA at the beginning of the study. This case had HCV genotype 1b, two other infected dialysis patients in the same unit had HCV genotypes 4k and 3a; thus precluding nosocomial transmission. Thanks to molecular and phylogenetic methods, one case of nosocomial HCV transmission in haemodialysis was confirmed. Epidemiological investigation suggested nosocomial transmission via the medical and/or nursing staff.     

Prevalence of hepatitis C virus antibody among Korean adults.

To estimate the prevalence of hepatitis C virus (HCV) infection among Korean adults and to present the putative route of HCV transmission among them, serum samples from 4917 adults older than 20 years of age were tested for antibody to HCV (anti-HCV), and histories of blood transfusion and other pertinent information were obtained by self-administered questionnaires. The overall prevalence of anti-HCV was 1.7%; prevalence was 1.4% in subjects with normal levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), 3.3% in those with slightly elevated and 5.9% in those with markedly elevated levels of the enzymes. The prevalence of anti-HCV increased with increasing age (P < 0.01), but was not associated with blood transfusion. The present study suggests that the prevalence of HCV infection was 1.4% and that the major routes of HCV transmission may be other than blood transfusion in healthy Korean adults.     

Lymphocytic choriomeningitis virus infection in a province of Spain: analysis of sera from the general population and wild rodents

Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne virus belonging to the family Arenaviridae, genus Arenavirus, which causes a wide spectrum of human disease. However, data on LCMV infection in Spain is scant. To investigate whether this virus causes infection in Spain, 400 serum samples from the general population (191 males, 209 females) and 100 from wild rodents were studied by immunofluorescence assay (IFA) using L-929 cells infected with LCMV. The study was performed in the "Community of Madrid," a region with both rural and urban areas in different ecological settings. Of the 400 human serum samples tested, antibodies against LCMV were detected in 7 (1.7%). No statistical differences in prevalence were found with respect to either age or rural or urban residence, but differences were seen with respect to sex. Nine (9%) of the rodent serum samples were positive. These results confirm the occurrence of LCMV infections in Man and rodents in Spain.     

Prevalence and mother-to-infant transmission of hepatitis viruses B, C, and E in Southern Tanzania.

Hepatitis B and C markers were tested in 980 pregnant women, in the infants born to infected mothers, and in a random sample of 42 and 50, respectively, children born to uninfected mothers in Tanzania. Sixty-two women (6.3%) were positive for HBsAg and 15 (24%) were HBeAg-seropositive. Anti-HCV was detected in 49 women (5%), 15 (31%) of whom had detectable viremia. HCV RNA serum levels were low and only genotype 4 was identified. Sixty-six women (6.7%) were positive for anti-HIV, six of whom were coinfected with HBV and one with HCV. Anti-HEV was negative in the 180 women tested. At 8 months of age, HBsAg was detected in 8% and 2% of children born to HBV-infected and noninfected mothers, respectively (P = 0.2). Corresponding figures at 18 months of age were 31% and 21% (P = 0.3). When tested at 2 months of age, HCV RNA was not detected in any of the 43 children born to anti-HCV-positive mothers nor in any of 50 children born to anti-HCV-negative mothers. At 18 months, only one child, born to an anti-HCV-positive mother, had detectable HCV RNA. None of the infants born to women with HIV coinfection were infected with hepatitis viruses. This study suggests that exposure to HEV does not occur in southern Tanzania. The prevalence of current HBV infection in pregnant women from rural Tanzania is lower than in other sub-Saharan areas. In early childhood, HBV infection appears to occur by horizontal rather than maternofilial mechanisms of transmission. The prevalence of HCV infection is similar to that in other African countries. The results of this study show for the first time in Africa that mother-to-infant transmission does not play a significant role in the acquisition of HCV infection.     

High prevalence of anti-hepatitis E virus antibodies in blood donors from South West France

Cases of autochthonous acute hepatitis E occur in most industrialized countries and are frequent in the South West of France. The prevalence of anti-hepatitis E virus (HEV) IgG antibodies in blood donors in this area was determined. A total of 529 samples from rural and urban blood donors were tested. The overall prevalence was 16.6%, 19.1% of rural donors and 14.2% of urban donors had anti-HEV antibodies (P = 0.13). The antibodies were widely distributed among all age groups and the sex ratio of the anti-HEV positive blood donors was 1.12 (P = 0.57). Hunting was the only pastime or profession associated with a high prevalence of anti-HEV antibodies (P = 0.038). The frequency of anti-HEV antibodies in blood donors could reflect active autochthonous transmission in this area of France. As the risk factors for HEV infection in industrialized countries are still unknown, further studies are needed to clarify the epidemiology of HEV infection in the Midi-Pyrénées region.     

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.     

Different seroprevalence and molecular epidemiology patterns of hepatitis C virus infection in Italy

The epidemiological picture of hepatitis C virus (HCV) infection in the general population is largely unknown, even in developed countries. The aim of this study was to estimate the prevalence and genotype distribution of HCV amongst a large sample of the Italian general population. A total of 3,577 serum samples were collected and screened for anti-HCV antibodies. ELISA and RIBA tests were used to assess the presence of anti-HCV. NS5b region sequencing was performed for molecular characterization. Of 3,577 tested sera, 95 (2.7%) were anti-HCV positive and a genome was detected and sequenced in 50 sera. The age-adjusted prevalence was 4.4%. Seroprevalence increased with age, following a North-South gradient, and increased steeply between the 15 and 30 and 31-45 age groups. Subtype 1b showed the highest prevalence in all geographical areas and age groups, followed by subtypes 2c (detected mainly in the elderly population in Southern Italy), 4a/d, and 3a (detected exclusively in adults) and 1a. These findings confirm that Central and Southern Italy are hyperendemic areas. The high prevalence observed in adults over age 30 is mainly attributable to an increase in 1b-prevalence but also to subtypes 2c- and 3/4-infections. Age-specific prevalence data and molecular characterization of the virus suggest that two transmission patterns co-exist in Italy: one characterized by subtype 1b and 2c infections, mainly in adults older than 60 years, and the other by subtype 3 and 4 infections, mainly in the 31-60 year age group, and consistent with intravenous drug use and immigration.     

Evidence for high genetic diversity and long-term endemicity of hepatitis C virus genotypes 1 and 2 in West Africa

During 1994 and 1995, the prevalence of hepatitis C virus (HCV) and its genotypes were studied in several rural and urban populations in three West African countries: Guinea, Burkina Faso, and Benin. The following groups were screened for antibodies to HCV (anti-HCV): 459 villagers in the forest region of Guinea; 965 individuals in urban, suburban, and rural populations of the Bobo Dioulasso area, Burkina Faso; and 582 blood donors in Cotonou, Benin. In Benin, 60 patients with sickle cell anemia (30 with and 30 without history of multiple transfusion) and 13 hospital patients with liver disease were also tested. RT-PCR detection of HCV-RNA was carried out on all anti-HCV positive samples, followed by genotyping and sequencing of unrecognized subtypes. The prevalence rates of anti-HCV were 1.1% in the Guinean population group, 1.4% among blood donors in Benin, and 4.9% in residents of Burkina Faso. In patients with sickle cell anemia, five of the 30 polytranfused patients (17%) had anti-HCV, whereas none of the patients without a history of blood transfusion had anti-HCV (P < 0.05). Among the 13 patients with liver disease, five had anti-HCV, of whom four had history of blood transfusion. HCV-RNA was detected in 41 anti-HCV positive sera. All belonged to genotypes 1 or 2, with a high genomic diversity; 18 different subtypes were identified, including 2c, 2d, and 16 new subtypes. Such genetic diversity poses a challenge for vaccine development and also implies that HCV infection is long-established in these West African regions. J. Med. Virol. 55:92–97, 1998. © 1998 Wiley-Liss, Inc.     

Simultaneously high prevalences of hepatitis B and C virus infections in a population in Putian County, China

This study investigated a rare area of endemicity with a high prevalence of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, in Putian County, China. Among 1,050 subjects, the overall prevalence of HBsAg seropositivity was 15.8%, and that of anti-HCV seropositivity was 28.9%. Intrafamilial viral transmission might be the major cause of the high prevalence of HBV infection in this region. However, HCV infection was shown to be associated with the use of inadequately sterilized medical equipment.     

HCV-related morbidity in a rural community of Egypt

The origin of the hepatitis C virus (HCV) epidemic in Egypt has been attributed to intravenous schistosomiasis treatment in rural areas in the 1960s to 70s. The objective of this study was to estimate the HCV-related morbidity in a rural area where mass schistosomiasis treatment campaigns took place 20-40 years before. The study sample included 2,425 village residents aged 18-65 years recruited through home-based visits. Overall, HCV antibody prevalence was 448/2,425 = 18.5% (95% CI = 16.9-20.1%), reaching 45% in males over 40 years, and 30% in females over 50 years. Of those with HCV antibodies, 284/448 (63.4%, 95% CI = 58.7-67.9%) had chronic HCV infection, among which 107/266 (40.2%, 95% CI = 34.3-46.4%) had elevated alanine aminotransferase (ALT). As part of pre-treatment screening, 26 consenting patients had a liver biopsy: 13 (50.0%) had a treatment indication. Thus, of all patients with HCV antibodies, 13 (2.9%) were eligible for treatment and willing to be treated. The relatively low level of morbidity observed in this study is discussed in view of co-factors of HCV infection progression, such as young age at infection, absence of alcohol intake, the prevalence of Schistosoma mansoni infection, and the prevalence of chronic hepatitis B.     

Prevalence and risk factors for viral hepatitis in the Kosovarian population: implications for health policy

The prevalence of hepatitis infection among the Kosovarian population is largely unknown. The aim of the study was to evaluate the prevalence and risk factors of hepatitis A, B, C, and D (HAV, HBV, HCV, HDV) infection among the general population and in a group of health care workers in the Kosovo region. Overall, 1,287 participants were recruited, 460 males (36%) and 827 females (64%). Health care workers accounted for 253 individuals (20%), 301 were blood donor candidates (23%), 334 were pregnant women (26%), and 399 (31%) were subjects who had been examined in two clinics for routine laboratory testing. The prevalence of total anti-HAV was 88.6% (95% CI: 86.69-90.25). Prevalence of anti-HAV among children up to 10 years was 40.5% (95% CI: 29.6-53.15), reaching 70% (95% CI: 62.25-77.10) in the 11-20 age group. Age, living in rural areas and unemployment were factors associated with higher risk of HAV infection. HBsAg was detected in 2.4% (95% CI: 1.57-3.38%) of the study sample, with a significant age trend (P-value:0.0110). Positivity for total anti-HBc was detected in 18.4% (95% CI = 16.27-20.59) of the subjects. Ninety-three subjects (7.2%) were positive for anti-HBs alone. An association between age, HSV-2 positivity, working nurses and HBV infection has been observed. One patient was HDV positive. The prevalence for HCV was 0.5% (95% CI: 0.22-1.12%). HAV infection seems to be high-intermediate, while HBV shows an intermediate endemicity. It is necessary to highlight the importance of an immunization strategy against HAV and HBV in reducing the incidence of the infection. The prevalence for HCV was very low.     

Hepatitis C virus infection in 2,744 hemodialysis patients followed regularly at nine centers in Hiroshima during November 1999 through February 2003

Patients on maintenance hemodialysis (HD) are at increased risk of infection with hepatitis C virus (HCV). A prospective follow-up study on HCV infection from November 1999 to February 2003 was conducted in nine hemodialysis (HD) units in Hiroshima. A total of 2,744 HD patients were surveyed regularly for HCV RNA in serum. The prevalence of HCV RNA decreased from 15.7% (262/1,664) on the first survey to 12.9% (242/1,882) in the last one (P<0.05). This decrease may be attributed to the inclusion of patients with a lower prevalence of HCV RNA compared to patients leaving dialysis centers (111/1,080 [10.3%] vs. 132/862 [15.3%], P<0.01). During the 40 months of this study, 16 de novo HCV infections were documented in the nine HD units corresponding to an incidence of 0.33% per year. These cases included eight new HCV infections, three re-infections, and five infections that presumably occured in the window period when tested during the first survey. Our study shows that the annual incidence of de novo HCV infection during HD was 0.33%, and emphasizes the need for frequent serum HCV RNA testing and for stringent disinfection procedures in order to prevent the transmission of HCV in these settings.