P926 High prevalence of left ventricular systolic dysfunction assessed by speckle tracking in asymptomatic HIV patients

Background

Cardiomyopathy presenting in people living with HIV (PLWHIV) has been attributed to the effect of inflammation, opportunistic infections, myocyte invasion and cardiac steatosis, while peripheral artery disease (PAD) is linked to immune activation, abnormalities in lipid metabolism, and traditional risk factors. The diagnosis of subclinical myocardial dysfunction and PAD could enable prompt implementation of therapeutic measures. However, data available to date on the specific topic are limited.

Μethods:We investigated the association between global longitudinal strain (GLS) and a) patient history, b) baseline characteristics, c) carotid intima-media thickness (IMT) and presence of carotid atheromatic plaque(s) d) temperature difference (ΔT) along each carotid artery, measured by microwave radiometry (MWR) and e) basic blood panel measurements, including high-sensitivity troponin-T(hsTnT) and NT-proBNP in PLWHIV and no history of cardiovascular disease.

Results

We prospectively enrolled forty asymptomatic PLWHIV on long-term highly active antiretroviral therapy. Thirty-seven (93%) were men, while mean age was 52 ± 13 years. Subclinical left ventricular systolic dysfunction(SLVSD), defined as a value of GLS> -18.7%, was present in 35% of patients. GLS value was significantly associated with age (r = 0.410,P = 0.013), history of hyperlipidemia (r = 0.370,P = 0.026), body mass index (r = 0.462,P = 0.005), waist circumference (r = 0.471,P = 0.007) and right bulb IMT (r = 0.390,P = 0.036). hs-TnT levels were significantly associated with age (r = 0.513, P = 0.001), CD4 count (r=-0.357,P = 0.025), serum creatinine (r = 0.338,P = 0.035) and the presence of carotid plaque (r = 0.374,P = 0.038). NT-proBNP levels were significantly associated with history of diabetes (r = 0.336,P = 0.048) and serum creatinine (r = 0.548,P = 0.001). No significant associations were demonstrated between carotid ΔΤ and other parameters.

Conclusion

Our results indicate that apart from age, a dysmetabolic component, expressed by higher BMI and history of hyperlipidemia, may be implicated in the pathogenesis of SLVSD, which may lead to cardiomyopathy, in PLWHIV.

Experiences of Stigma and Support Reported by Participants in a Network Intervention to Reduce HIV Transmission in Athens, Greece; Odessa, Ukraine; and Chicago, Illinois

A growing body of evidence suggests that network-based interventions to reduce HIV transmission and/or improve HIV-related health outcomes have an important place in public health efforts to move towards 90-90-90 goals. However, the social processes involved in network-based recruitment may pose a risk to participants of increasing HIV-related stigma if network recruitment causes HIV status to be assumed, inferred, or disclosed. On the other hand, the social processes involved in network-based recruitment to HIV testing may also encourage HIV-related social support. Yet despite the relevance of these processes to both network-based interventions and to other more common interventions (e.g., partner services), there is a dearth of literature that directly examines them among participants of such interventions. Furthermore, both HIV-related stigma and social support may influence participants' willingness and ability to recruit their network members to the study. This paper examines (1) the extent to which stigma and support were experienced by participants in the Transmission Reduction Intervention Project (TRIP), a risk network-tracing intervention aimed at locating recently HIV-infected and/or undiagnosed HIV-infected people and linking them to care in Athens, Greece; Odessa, Ukraine; and Chicago, Illinois; and (2) whether stigma and support predicted participant engagement in the intervention. Overall, experiences of stigma were infrequent and experiences of support frequent, with significant variation between study sites. Experiences and perceptions of HIV-related stigma did not change significantly between baseline and six-month follow-up for the full TRIP sample, and significantly decreased during the course of the study at the Chicago site. Experiences of HIV-related support significantly increased among recently-HIV-infected participants at all sites, and among all participants at the Odessa site. Both stigma and support were found to predict participants' recruitment of network members to the study at the Athens site, and to predict participants' interviewer-rated enthusiasm for naming and recruiting their network members at both the Athens and Odessa sites. These findings suggest that network-based interventions like TRIP which aim to reduce HIV transmission likely do not increase stigma-related risks to participants, and may even encourage increased social support among network members. However, the present study is limited by its associational design and by some variation in implementation by study site. Future research should directly assess contextual differences to improve understanding of the implications of site-level variation in stigma and support for the implementation of network-based interventions, given the finding that these constructs predict participants' recruitment of network members and engagement in the intervention, and thereby could limit network-based interventions' abilities to reach those most in need of HIV testing and care.

Prevalence of drug resistance among HIV-1 treatment-naive patients in Greece during 2003-2015: Transmitted drug resistance is due to onward transmissions

BACKGROUND

The prevalence of HIV-1 drug resistance among treatment-naïve patients ranges between 8.3% and 15% in Europe and North America. Previous studies showed that subtypes A and B were the most prevalent in the Greek HIV-1 epidemic. Our aim was to estimate the prevalence of resistance among drug naïve patients in Greece and to investigate the levels of transmission networking among those carrying resistant strains.

METHODS

HIV-1 sequences were determined from 3428 drug naïve HIV-1 patients, in Greece sampled during 01/01/2003-30/6/2015. Transmission clusters were estimated by means of phylogenetic analysis including as references sequences from patients failing antiretroviral treatment in Greece and sequences sampled globally.

RESULTS

The proportion of sequences with SDRMs was 5.98% (n=205). The most prevalent SDRMs were found for NNRTIs (3.76%), followed by N(t)RTIs (2.28%) and PIs (1.02%). The resistance prevalence was 22.2% based on all mutations associated with resistance estimated using the HIVdb resistance interpretation algorithm. Resistance to NNRTIs was the most common (16.9%) followed by PIs (4.9%) and N(t)RTIs (2.8%). The most frequently observed NNRTI resistant mutations were E138A (7.7%), E138Q (4.0%), K103N (2.3%) and V179D (1.3%). The majority of subtype A sequences (89.7%; 245 out of 273) with the dominant NNRTI resistance mutations (E138A, K103N, E138Q, V179D) were found to belong to monophyletic clusters suggesting regional dispersal. For subtype B, 68.1% (139 out of 204) of resistant strains (E138A, K103N, E138Q V179D) belonged to clusters. For N(t)RTI-resistance, evidence for regional dispersal was found for 27.3% and 21.6% of subtype A and B sequences, respectively.

CONCLUSIONS

The TDR rate based on the prevalence of SDRM is lower than the average rate in Europe. However, the prevalence of NNRTI resistance estimated using the HIVdb approach, is high in Greece and it is mostly due to onward transmissions among drug-naïve patients.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Public perceptions in relation to intention to receive pandemic influenza vaccination in a random population sample: evidence from a cross-sectional telephone survey

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Public perceptions in relation to intention to receive pandemic influenza vaccination in a random population sample: evidence from a cross-sectional telephone survey

A cross-sectional telephone survey on a nationally representative sample of 1,000 Greek households was performed to assess the acceptability of the pandemic influenza A(H1N1)v vaccine, factors associated with intention to decline and stated reasons for declining vaccination. The survey was initiated the last week of August 2009 (week 35) and is still ongoing (analysis up to week 44). The percentage of participants answering they would probably not/definitely not accept the vaccine increased from 47.1% in week 35 to 63.1% in week 44 (test for trend: p<0.001). More than half of the people which chronic illnesses (53.3%) indicated probably not/definitely not. Factors associated with intention to decline vaccination were female sex, age between 30-64 years, perception of low likelihood of getting infected or of low risk associated with influenza, and absence of household members suffering from chronic illnesses. For the majority of the respondents (59.8%), the main reason for intending to decline vaccination was the belief that the vaccine might not be safe. Promotion of vaccination programmes should be designed taking into account the attitudinal barriers to the pandemic vaccine.

Ongoing epidemic of blaVIM-1-positive Klebsiella pneumoniae in Athens, Greece: a prospective survey

OBJECTIVES

To determine the current frequency and study the characteristics of VIM-1-producing Klebsiella pneumoniae isolates from bloodstream infections in Greek hospitals.

METHODS

All blood isolates of K. pneumoniae were prospectively collected during 2004-06 in three teaching hospitals located in Athens. MICs of antibiotics were determined by the Etest. Extended-spectrum- (ESBL) and metallo-beta-lactamase (MBL) production was examined by clavulanate- and EDTA-based techniques, respectively. Isolates were typed by PFGE of XbaI-digested genomic DNA. Detection of bla(VIM-1) and mapping of the VIM-1-encoding integrons were performed by PCR and sequencing. Beta-lactamase activities were analysed by IEF and imipenem hydrolysis was assessed by spectrophotometry. VIM-1-encoding plasmids were transferred to Escherichia coli by conjugation and transformation and characterized by Inc/rep typing and RFLP.

RESULTS

Sixty-seven (37.6%) of 178 K. pneumoniae blood isolates were bla(VIM-1)-positive (VPKP); 77.8% of these were from ICUs. All VPKP isolates were multidrug-resistant. The MICs of carbapenems for VPKP varied from the susceptible range to high-level resistance overlapping with those of MBL-negative isolates. The EDTA-imipenem synergy methods had reduced sensitivity in detecting VPKP isolates when the MICs were in the susceptible range. ESBL production was common among VPKP isolates (n = 45, 67.2%) as indicated by resistance to aztreonam and confirmed by a clavulanate-based double-disc synergy test. The responsible ESBL was always an SHV-5-type enzyme as indicated by IEF. PFGE identified eight clusters (A-H) of VPKP isolates with related (>80%) patterns, as well as four unique types. Both inter-hospital spread of several clones and genotypic similarities among susceptible, ESBL-positive and VPKP isolates were also observed. Location of bla(VIM-1) and expression of VIM-1 were studied in 12 isolates representing the eight PFGE clusters. In all isolates, bla(VIM-1) was part of a class 1 integron that also carried aacA4, dhfrI, aadA and sulI. In eight isolates (clusters C, D, G and H), the bla(VIM-1) integron was located in transferable IncN plasmids. A cluster F isolate carried a VIM-1-encoding, self-transferable plasmid that was not typeable by Inc/rep typing. VIM-1-encodingreplicons were not identified in three isolates (PFGE clusters A, B and E). VPKP isolates exhibited differences in imipenem-hydrolysing activities which, however, were not correlated with the respective carbapenem MICs.

CONCLUSIONS

A multiclonal epidemic of bla(VIM-1)-carrying K. pneumoniae is under way in the majorhospitals in Greece. Microorganisms producing both VIM-1 and SHV-5 constitute the prevalent multidrug-resistant population of K. pneumoniae in this setting.

Cholestatic syndrome with bile duct damage and loss in renal transplant recipients with HCV infection

BACKGROUND/AIMS

Bile duct cells are known to be susceptible to hepatitis B and C virus, while it has been recently suggested that hepatitis B virus (HBV) and hepatitis C virus (HCV) infection may have a direct role in the pathogenesis of vanishing bile duct syndrome (VBDS) after liver transplantation. We report the development of a cholestatic syndrome associated with bile duct damage and loss in four HCV-infected renal transplant recipients.

METHODS

All four patients were followed up biochemically, serologically and with consecutive liver biopsies. Serum HCV RNA was quantitatively assessed and genotyping was performed.

RESULTS

Three patients were anti-HCV negative and one was anti-HCV/HBsAg positive at the time of transplantation and received the combination of methylprednisolone, azathioprine and cyclosporine A. Two patients became anti-HCV positive 1 year and one patient 3 years post-transplantation. Elevation of the cholestatic enzymes appeared simultaneously with seroconversion, or 2-4 years later, and was related to lesions of the small-sized interlobular bile ducts. Early bile duct lesions were characterized by degenerative changes of the epithelium. Late and more severe bile duct damage was associated with bile duct loss. The progression of the cholestatic syndrome coincided with high HCV RNA serum levels, while HCV genotype was 1a and 1b. Two patients (one with HBV co-infection) developed progressive VBDS and died of liver failure 2 and 3 years after biochemical onset. One patient, despite developing VBDS within a 10-month period, showed marked improvement of liver function after cessation of immunosuppression because of graft loss. The fourth patient, who had mild biochemical and histological bile duct changes, almost normalized liver function tests after withdrawal of azathioprine.

CONCLUSION

A progressive cholestatic syndrome due to bile duct damage and loss may develop in renal transplant patients with HCV infection. The occurrence of the lesions after the appearance of anti-HCV antibodies and the high HCV RNA levels are indicative of viral involvement in the pathogenesis. Withdrawal of immunosuppressive therapy may have a beneficial effect on the outcome of the disease.

Fibrosing cholestatic hepatitis in renal transplant recipients with hepatitis C virus infection

Fibrosing cholestatic hepatitis (FCH) has been described as a specific manifestation of hepatitis B virus (HBV) infection in liver allograft recipients characterized by a rapid progression to liver failure. Only sporadic cases have been reported in other immunocompromised groups infected with HBV and in a few transplant recipients with hepatitis C virus (HCV) infection. We present the occurrence of FCH in 4 HCV-infected renal transplant recipients within a series of 73 renal transplant recipients with HCV infection followed up closely serologically and with consecutive liver biopsies. All 4 patients received the triple-immunosuppressive regimen (azathioprine, cyclosporine A, methylprednisolone). The interval from transplantation to the appearance of liver dysfunction was 1 to 4 months and to histological diagnosis, 3 to 11 months. The biochemical profile was analogous to a progressive cholestatic syndrome in 3 patients, whereas the fourth patient had only slightly increased alanine aminotransferase and gamma-glutamyl transferase (gammaGT) levels. Liver histological examination showed the characteristic pattern of FCH in 2 patients, whereas the other 2 patients had changes compatible with an early stage. All patients were anti-HCV negative at the time of transplantation, whereas 2 patients, 1 with incomplete and 1with complete histological FCH features, seroconverted after 3 and 31 months, respectively. The patients were HCV RNA positive at the time of the first liver biopsy and showed high serum HCV RNA levels (14 to 58 x 10(6) Eq/mL, branched DNA). HCV genotype was 1b in 3 patients and 3a in 1 patient. After histological diagnosis, immunosuppression was drastically reduced. Two patients died of sepsis and liver failure 16 and 18 months posttransplantation, whereas the seroconverted patients showed marked improvement of their liver disease, which was histologically verified in 1 patient. In conclusion, FCH can occur in HCV-infected renal transplant recipients. It seems to develop as a complication of a recent HCV infection during the period of maximal immunosuppression and is associated with high HCV viremia levels. There are indications that drastic reduction of immunosuppression may have a beneficial effect on the outcome of the disease.

Prevalence patterns and genotypes of GB virus C/hepatitis G virus among imprisoned intravenous drug users

An RT-PCR assay using primers from the 5'-UTR of the GBV-C/HGV genome was used to detect viremia, and a serological assay was used to detect past exposure to GBV-C/HGV, in sera from 106 imprisoned Greek intravenous drug users. High seroprevalence rates indicative of the parenteral route of transmission of the virus were found (32.1% for GBV-C RNA and 46.2% for anti-GBV-C E2). These rates were nonetheless lower in comparison to the corresponding rates of HCV infection markers (64.2% for HCV RNA and 77.4% for anti-HCV). Statistically significant univariate associations were observed between GBV-C-RNA positivity and younger age (P=0.006) and HCV-RNA positivity (P=0.024), as well as with higher serum alanine aminotransferase levels (P< 0.001); this latter association was shown to be independent of coinfection with HCV and of age by a multiple logistic regression model. Apparently, GBV-C/HGV had spread readily by needle-sharing in prison, while causing acute subclinical hepatitis in infected inmates. Phylogenetic analysis of the partial 5'-UTR of the GBV-C/HGV genome from 16 seropositive individuals, which delineated their grouping within genotype 2, also revealed a close genetic relationship between two sets of sequences from 4 drug addicts, 3 of whom admitted to sharing needles while imprisoned.

A survey of bloodborne viruses and associated risk behaviours in Greek prisons

AIMS

To determine HIV and hepatitis infection prevalence and correlates with risk behaviour.

DESIGN

Cross-sectional study: voluntary, anonymous HIV, hepatitis (HCV, HBV and HDV) surveillance and questionnaire on risk factors.

SETTING

Korydallos Prison, Athens and Ag. Stefanos Prison, Patra, Greece.

PARTICIPANTS

Of 544 drug users imprisoned for drug related offences, all completed the questionnaire and 533 blood samples were collected.

MEASUREMENTS

HIV (by anti-HIV-1), HCV (by anti-HCV), HBV (by anti-HBc, HBsAg) and HDV (by anti-HDV) prevalence. Data on demography, legal status, drug use, sharing of injecting equipment.

FINDINGS

Of the 544 drug users, 375 (68.9%) had injected drugs (IDUs) at some time, 35% of whom had injected whilst in that prison. Of the 533 blood samples tested, one was positive for anti-HIV-1 (0.19%), 310 for anti-HCV (58.2%), 306/531 (57.6%) for anti-HBc, 34/527 (6.5%) for HBsAg and 12/527 (2.3%) for anti-HDV. Prevalence rates for IDUs only were 0.27% for HIV-1, 80.6% for hepatitis C, 62.7% for hepatitis B and 3.3% for hepatitis D. Ninety-two per cent of IDUs injecting in prison shared needles, indicating that IDUs inject less but share more during incarceration. Multiple logistic regression revealed needle-sharing as the most important risk factor for HCV infection in IDUs. Prior knowledge of a positive hepatitis result did not appear to inhibit IDUs from practising risky behaviours in prison.

CONCLUSIONS

The epidemic of hepatitis B and C among imprisoned IDUs identified by this study constitutes a major public health problem. Prevention programmes, such as counselling, HBV vaccination, community-based methadone maintenance treatment and syringe exchange schemes, are necessary in order to prevent a further spread.

Immunologic events during the incubation period of hepatitis C virus infection: the role of antibodies to E2 glycoprotein. Multicentre Hemodialysis Cohort Study on Viral Hepatitis

BACKGROUND

The study of the sensitivity of screening assays is greatly facilitated by testing the sequential changes in seroconverting individuals. The aim of this study was to investigate the early immunologic response after hepatitis C virus (HCV) infection and to evaluate whether HCV envelope (E2) recombinant antigen would provide a significant increase in sensitivity for detection of anti-HCV.

STUDY DESIGN AND METHODS

Twenty hemodialysis patients who were seroconverting to anti-HCV were included in this study. They were followed up for a mean period (+/- SD) of 10.5 +/- 3.3 months, in which 13 to 46 serum samples per case were collected. Each sample was tested for anti-HCV by second- and third-generation enzyme immunoassay (EIA-2 and EIA-3) and recombinant immunoblot assay (RIBA-3). E2 antibodies were tested by a prototype EIA in which E2 was expressed as a recombinant antigen in Chinese hamster ovary cells.

RESULTS

Alanine aminotransferase elevation was observed in 18 of 20 cases. Reactivity against c100, c33c, c22, NS5, and E2 was detected in 15 (75%), 19 (95%), 15 (75%), 2 (10%), and 17 (85%) patients, respectively; c33c was the most immunogenic antigen, followed in descending order by E2, c22, c100, and NS5. E2 antibody reactivity resolved the two RIBA-3-indeterminate cases. However, there was no case in which E2 reactivity preceded all other HCV antigens. Anti-E2 was found to react in all patients of genotypes 1a, 1b, and 3a but in only 2 of 4 patients of genotype 4a.

CONCLUSION

In this group of seroconverting individuals, E2 antigen was shown to be highly immunoreactive and did resolve some RIBA-3-indeterminate samples as being positive, on the basis of reactivity to multiple antigens, but it did not improve early detection of seroconversion.

Hepatitis E virus (HEV) infection in haemodialysis patients. The Multicentre Haemodialysis Cohort Study on Viral Hepatitis

BACKGROUND

The aim of this study was to determine the prevalence of hepatitis E virus (HEV) infection among patients undergoing haemodialysis (HD) and to evaluate whether chronic haemodialysis is associated with an increased risk of HEV infection.

METHODS

Serum samples from 420 HD patients and 316 healthy volunteers were tested for IgG and IgM antibodies to HEV (anti-HEV). Anti-HEV IgG positive sera were confirmed using synthetic peptides.

RESULTS

Anti-HEV IgG was confirmed in 27/420 (6.4%) of the HD patients and in 7/316 (2. 2%) of the reference group (P=0.07). However, multiple logistic regression analysis showed that the prevalence of anti-HEV IgG was not significantly higher in HD patients compared with the reference group, after controlling for age and sex. No patient was found positive for anti-HEV IgM. The presence of anti-HEV was associated with sex in HD patients (P=0.04). No significant association was found between anti-HEV and underlying renal disease, anti-HCV, anti-HBc, blood transfusions, history of elevated transaminases, history of clinical hepatitis and renal transplantation. A marginal association, which was observed with the duration of haemodialysis in univariate analysis (P=0.07), was not confirmed in multivariate analysis.

CONCLUSIONS

Chronic haemodialysis is not associated with an increased risk of exposure to HEV, and the high prevalence of anti-HEV IgG in HD patients reported in uncontrolled studies is possibly due to the confounding effect of age and sex.

Prevalence study of different hepatitis markers among pregnant Albanian refugees in Greece

Aim of the study was to record the prevalence of the various types of viral hepatitis, especially hepatitis B, in pregnant Albanian refugees in Greece. The study comprised 500 pregnant refugees of mean age 25.1 +/- 4.6 years. In Albania, all women had lived in overcrowded houses and had been exposed to non throw-away needles and syringes. Various indices for all hepatitis types were determined. The prevalence of HBsAg was 13.4%, of anti-HBs 53%, of total anti-HBc 70.8%, of anti-HBc IgM 0.4%, of HBeAg 1.2%, of anti-HBe 58.6%, of anti-HAV 96.2%, of anti-HAV IgM 1%, of anti-HDV 0.4%, of anti-HCV 0.6% and of anti-HEV 2%. HBeAg was found positive in 7.5% of HBsAg carriers. Prevalence of hepatitis B markers, as determined by HBsAg and/or anti-HBs and/or total anti-HBc was significantly higher in those with a history of previous hospitalization in Albania (p = 0.01) and those with previous history of hepatitis (p = 0.02). The high prevalence of hepatitis B markers in pregnant Albanian refugees proves that HBV infection is highly endemic in Albania and the possibility of perinatal transmission to the offsprings urges for HBV vaccination programmes. On the other hand improvements in the socioeconomic conditions and the sanitation system in Albania is anticipated to reduce the incidence of HAV and HBV infections.

Hepatitis E virus infection in individuals at high risk of transmission of non-A, non-B hepatitis and sexually transmitted diseases

The aim of the study was to determine the prevalence of hepatitis E virus (HEV) infection among individuals at high risk of transmission of non-A, non-B hepatitis or sexually transmitted diseases (STDs), and to evaluate whether they have an increased risk of exposure to HEV. Serum samples from 125 thalassemia patients, 300 intravenous drug users, 420 hemodialysis patients, 263 individuals with STDs, 47 human immunodeficiency virus (HIV) infected homosexual men, and 316 healthy volunteers were tested for immunoglobulin G (IgG) and M (IgM) antibodies to HEV (anti-HEV) by enzyme immunoassays (EIAs) following a predetermined algorithm (Abbott Labs). Anti-HEV IgG was confirmed in 3/125 (2.4%) thalassemia patients, 5/300 (1.7%) intravenous drug users, 27/420 (6.4%) hemodialysis patients, 4/263 (1.5%) STD patients, 1/47 (2.1%) homosexual men, and 7/316 (2.2%) of the reference group. No patient was found positive for anti-HEV IgM. The higher prevalence which was observed in hemodialysis group was due to the confounding effect of age, as multivariate analysis showed. The anti-HEV prevalence increased significantly with age (p = 10(-4)). No significant association was found between anti-HEV, anti-HCV, and anti-HBc. In conclusion, individuals at high risk of non-A, non-B hepatitis and STDs have no increased risk of exposure to HEV and the higher prevalence of anti-HEV IgG among older subjects may be due to an epidemic form of HEV infection which occurred some decades ago, when the sanitary conditions in our country were poor.