Suboptimal MMR Vaccination Coverages-A Constant Challenge for Measles Elimination in Romania

Measles is targeted for elimination since 2001, with a significant reduction in cases recorded worldwide, but outbreaks occur periodically due to immunization gaps. This study analyzes the evolution of vaccination coverage rates (VCRs) in Romania, a EU country with large measles epidemics during the last two decades, including an ongoing outbreak in 2023. Vaccination against measles has been part of the National Immunization Program since 1979, initially as a single dose, and from 1994 onwards it has had two doses. The initially high national VCRs of >97% gradually declined from 2010 onward and remained constantly under 90%, with further decreases during the COVID-19 pandemic. The lowest VCRs for both vaccine doses in the last decade were recorded in 2022 and were 83.4% for the first dose and 71.4% for the second dose, with significant differences among Romania's 42 counties. Several factors contributed to this decline, including failure to attend the general practitioners' offices, increased number of children lost to follow-up due to population movements, missed vaccination opportunities due to temporary medical contraindications, a surge in vaccine hesitancy/refusal, a decreasing number of general practitioners and discontinuities in vaccine supply. The persisting suboptimal VCRs in Romania threaten the progress toward measles elimination.

HIV-HBV Coinfection-Current Challenges for Virologic Monitoring

HIV-HBV coinfected patients have higher rates of liver-related morbidity, hospitalizations, and mortality compared to HBV or HIV mono-infected ones. Clinical studies have shown an accelerated progression of liver fibrosis and an increased incidence of HCC, resulting from the combined action of HBV replication, immune-mediated hepatocytolysis, and HIV-induced immunosuppression and immunosenescence. Antiviral therapy based on dually active antiretrovirals is highly efficient, but late initiation, global disparities in accessibility, suboptimal regimens, and adherence issues may limit its impact on the development of end-stage liver disease. In this paper, we review the mechanisms of liver injuries in HIV-HBV coinfected patients and the novel biomarkers that can be used for treatment monitoring in HIV-HBV coinfected persons: markers that assess viral suppression, markers for liver fibrosis evaluation, and predictors of oncogenesis.

HIV transmission clusters among injecting drug users in Romania

Injection drug use is increasingly an important route of HIV transmission in Romania (from 1.5% of the newly diagnosed cases prior to 2010 to 31% in 2013). In this study we investigated the viral characteristics and relationships in newly HIV infected persons who inject drugs in Bucharest, Romania.

RESULTS

HIV-1 pol sequencing, followed by phylogenetic and clustering analysis was performed on blood from 37 injecting drug users (IDUs) newly diagnosed with HIV infection. While HIV subtype F1, the dominant strain in Romania since 1990, remains prevalent, new subtypes were found including G, B, B/G and B/F recombinants. Overall, 27 of the available sequences (72.9%) clustered with at least one other. Network and phylogenetic analysis revealed tight monophyletic clusters for both subtypes F and G, with short genetic distances between sequences, suggesting recent numerous acute to acute transmissions or single burst-type episodes. No transmitted drug-resistance mutations were identified. Greater immunosuppression was present in subjects forming the subtype G cluster, possibly indicating a faster rate of progression associated with this subtype.

CONCLUSIONS

The recent increasing numbers of IDU related HIV transmissions in Bucharest, has resulted in closely-knit transmission networks that maychange the genetic profile of the local HIV epidemic.

HCV non-1b genotypes in injecting drug users from Romania

INTRODUCTION

Chronic hepatitis C cases diagnosed in Romania were mostly related to unsafe parenteral treatments and blood transfusions; HCV genotype 1b was prevalent. During the last decade, an increasing number of HCV infections was reported among people who inject drugs (PWID). The aim of the current study was to test if this epidemiological shift triggered a diversification of the circulating viral strains.

METHODOLOGY

HCV genotypes were determined by reverse hybridization in 130 HCV-infected PWID (87.7% males; mean age 27.9 ± 6.7 years, injecting drugs for 8.1 ± 4.8 years).

RESULTS

HIV-HCV co-infection was diagnosed in 80.8% of the subjects and 26.9% were HIV-HCV-HBV triple infected. Active HCV viral replication was present in 104 PWID (80%), more frequently in those HIV-co-infected (91.4% vs. 52% in HCV mono-infected, and 77.148.5% in HIV-HCV-HBV triple-infected, p = 0.0001). Non-1b genotypes were prevalent (54.8%), with subtype 1a the most commonly detected (24%), followed by genotypes 3a (14.4%) and 4 (7.7%). Mixed infections with genotypes 1a and 1b were found in nine subjects (8.7%). There was no difference in the genotypes frequencies based on HIV or HBV co-infection status, length of drug usage, or associated risk factors (tattoos, piercing, detention).

CONCLUSION

The continuous surveillance of HCV genotypes in PWID from Romania will add valuable information to the overall European epidemiological picture, with important therapeutic implications.

Injecting drug use: A vector for the introduction of new hepatitis C virus genotypes

Hepatitis C virus (HCV) genotypes’ monitoring allows real-time insight into the dynamic changes that occur in the global epidemiological picture of HCV infection. Intravenous drug use is currently the primary driver for HCV transmission in developed and developing countries. The distribution of HCV genotypes/subtypes differs significantly between people who inject drugs (PWID) and the general population. HCV genotypes that previously exhibited a limited geographical distribution (3a, 4) are becoming more prevalent in this high-risk group. Immigration from HCV-endemic countries and the evolving networks of HCV transmission in PWID influence HCV genotypes distribution in Europe. Social vulnerabilities (e.g., unemployment, homelessness, and limited access to social and healthcare insurances systems) are important triggers for illicit drug use, which increases the associated risks of HCV infection and the frequent emergence of less prevalent genotypes. Genotype/subtype determination bears important clinical consequences in the progression of liver disease, susceptibility to antiviral therapies and the emergence of resistance-associated variants. An estimated half of the chronically HCV-infected PWID are unaware of their infection, and only one in ten of those diagnosed enter treatment. Nevertheless, PWID exhibit high response rates to new antiviral regimens, and the level of HCV reinfection is unexpectedly low. The focus of the healthcare system must be on the early detection and treatment of infection, to avoid late presentations that are associated with high levels of viremia and liver fibrosis, which may diminish the therapeutic success rate.

Influence of Staphylococcus aureus attachment to the herpes simplex virus infected cells

The purpose of this study was to investigate the response of HeLa cells to the interaction with inactivated Staphylococcus aureus cells and live challenge with herpes simplex virus (HSV).The results of this study are indicating that the interaction between the HeLa cells and S. aureus inactivated whole cells could modulate the host cell apoptosis and cytokine production, and therefore, influence the progression of HSV infection. The pre-treatment of HeLa cells with heat inactivated bacterial whole cells protects them from the occurrence of HSV mediated cytopathic effect, while the post viral infection treatment with bacterial cells prevents the high activation of bax/bcl-2 apoptotic pathway, a process that could change the fate of the infectious process triggered by the virus, and eventually reduce its multiplication rate. The pre-treatment of HeLa monolayer with inactivated bacterial cells 24 hours before the viral infection is increasing the expression level of TNF-a, IL-6 and IL-8 pro-inflammatory cytokines genes, also suggesting that bacterial antigens could contribute to the decrease of viral multiplication rate.

The effectiveness of cytological rescreening in the reduction of false negative/positive Pap reports

BACKGROUND

Cytological investigation of the cervix has proven to be a valuable tool in the early detection of cervical cancer; however, the high incidence of false negative or false positive smear reports is an important drawback.

OBJECTIVES

To investigate retrospectively the value of partial rescreening methods as tools for improving the sensitivity and specificity of Pap test routine screening.

METHODS

Out of a total of 4664 cervical samples examined by Pap test, 20% were randomly selected and rescreened with a more detailed examining protocol by the same cytologist; in addition, targeted rescreening of all samples with severe lesions was carried out.

RESULTS

During initial testing, 478 smears (10.24%) showed cytological abnormalities, classified as ASC-US (5.79%); L-SIL (3.32%) and H-SIL (1.14%). At random rescreening, a significant decrease in the number of negative smears (83.05% vs. 85.9%, p = 0.036) was recorded, together with an increase (7.68% vs. 5.79%, p = 0.043) in the number of smears classified as ASC-US. No significant differences were recorded for L-SIL or H-SIL samples. Retrospective targeted rescreening of all 208 samples initially diagnosed as L-SIL and H-SIL revealed 42 false positive results and 12 false negative ones. Errors were linked to suboptimal smear preparation: scant cellularity, material in clumps, paucity of abnormal cells, pale dyskarosis, small microbiopsy- like aggregates.

CONCLUSION

Partial random rescreening or targeted rescreening enables a better interpretation of suboptimal prepared smears. Targeted rescreening allows a correct detection of even low percentages of atypical cells. Other confounding factors, such as the laboratory workload and the regional prevalence of the disease, can exert an important effect on the correct classification of cytological lesions.

New interferons in the treatment of chronic hepatitis C

The current standard therapy for chronic HCV infection is a combination of pegylated-interferon (PEG-IFN) and weight-based ribavirin, administered for 24-48 weeks, according to the viral genotype. Although the weekly administration of pegylated interferons provides superior antiviral efficacy over standard interferon alpha, the rate of sustained virological response rarely overpasses 50% in patients infected with HCV genotypes 1 and 4. Consequently, multiple clinical trials with congeners of interferon (consensus interferon, interferon lambda, albinterferon, and controlled-release interferons) are ongoing. Their main advantages consist in maintenance of viral suppression across a longer dosing interval, avoidance of interdose trough and reduced dosing frequencies (twice or even once per month compared to once per week for the actual PEG-IFNs). Along with these superior pharmacokinetic properties, new interferons are expected to have improved side-effect profiles and better tolerability compared with the currently available formulations, providing an option for otherwise difficult to treat, challenging populations. New interferon formulation can be incorporated into future combination with direct acting antivirals, in order to maintain viral suppression over longer periods and minimize the development of viral resistance.

Tracking down of laryngo-pharyngeal metastasis

BACKGROUND

In Romania, the most optimistic statistics give a 5 years survival rate in approximately 33% of laryngo-pharyngeal cancer patients. Considering that a cell carrying the viral DNA is originating from primary tumor, we have tested whether HPV DNA could be detected in the blood cell of patients with laryngeal cancer as a marker of disease progression and metastases.

METHODS

The study was performed on 85 patients (59 +/- 8.7 age) with laryngo-pharyngeal cancer. HPV DNA was detected in tumor using nested PCR with consensus primers, and also in local lymph nodes and/or blood cells from patients HPV positive in primary tumor.

RESULTS

HPV DNA was detected in 75.29% of analyzed tumours, and all HPV16 positive samples were confirmed by mRNA E6 expression. 56.3% of patients presented HPV DNA in peripheral circulation as confirmed by PCR with E6 HPV16 specific primers followed by Southern Blot.

CONCLUSION

Our results sustain that the detection of HPV DNA in blood is a "surrogate marker" of metastasis when extension of metastasis cannot be estimated, this observation is very important for management of cancer patients with laryngopharyngeal localization.

Influence of social changes on the evolution of HIV infection in Romania

The Romanian HIV epidemic started and evolved as a paediatric one, accounting for more than a quarter of the total European juvenile AIDS cases. In response to this major AIDS outbreak, emphasis was placed on the patient's treatment, by implementation of a free, universal access program of Highly Active AntiRetroviral Therapy. This approach has been highly successful, and has greatly increased the rate of survival in infected children. Nevertheless, these children are now teenagers or young adults, representing a large cohort of "long term survivors"- a unique population that represent a great challenge for the public health system and for their integration in the civil society. As the number of HIV infected adults is increasing, new high-risk behaviour groups, as well as vulnerable populations (young people, people living in poverty, Rroma community) need to be reached in prevention programs. This article explores the impact of the socio-economic changes on the evolution of the HIV epidemic in Romania and speculates about the factors that might drive future increases in the incidence of HIV infections.

Alternatives to HIV-RNA and CD4 count to monitor HIV disease progression: a prospective cohort study in Romania

Little evidence exists on how to efficiently and effectively monitor HIV-disease progression in developing countries. Better understanding regarding cost-effective tests may help to resolve questions regarding treatment. A prospective cohort study was conducted with a 1-year follow-up period. Immune complex-dissociated (ICD) p24 antigen (ICD p24Ag), alone or in combination with HIV p24 antibody (p24Ab), was compared to HIV-RNA and CD4+ count in a cohort of 160 HIV-infected adolescents in Romania. The main outcome measure was disease progression, defined as >50,000 copies/ml of HIV-RNA or death. Among the 160 adolescents, a higher mean ICD p24Ag was significantly associated with clinical disease classification (CDC), plasma HIV-RNA concentration, and p24Ab. Multivariate logistic regression showed detectable ICD p24Ag had an odds ratio of 3.7 (95% CI 1.4-9.7) for disease progression in comparison to undetectable ICD p24Ag. ICD p24Ag is of value in determining the prognosis of disease in HIV-1-infected adolescents in developing countries. Additional studies for validation of this assay for HIV clades primarily affecting developing countries, are now needed.

High prevalence of hepatitis B virus markers in Romanian adolescents with human immunodeficiency virus infection

BACKGROUND

We evaluated the frequency of hepatitis coinfection in Romanian adolescents who were diagnosed with human immunodeficiency virus (HIV) infection prior to 1995.

METHODS

One hundred sixty-one adolescents (13-18 years of age) with symptomatic HIV infection, but without signs of hepatic dysfunction, and 356 age-matched, HIV-uninfected controls underwent laboratory testing for markers of parenterally acquired hepatitis virus infection.

RESULTS

Seventy-eight percent of HIV-infected adolescents had markers of past or present hepatitis B virus (HBV) infection, as compared with 32% of controls ( P = .0001). The prevalence of HBV replicative markers was more than 5-fold higher in HIV-infected adolescents as compared with controls: 43.4% vs 7.9% ( P = .0001), respectively, for hepatitis B surface antigen (HBsAg); and 11.2% vs 2.2% ( P = .0001), respectively, for hepatitis B e antigen (HBeAg). The prevalence of HBsAg chronic carriers and the presence of HBV replicative markers was significantly higher in patients with immunologically defined AIDS (CD4+ cell counts < 200 cells/mcL): 59.6% vs 34.6% ( P = .02) for HBsAg and 22.8% vs 5.7 %, ( P = .002) for HBV DNA. After 1 year of follow-up, the proportion of those who cleared the HBeAg was considerably lower in severely immunosuppressed coinfected patients: 4.7% vs 37.1% ( P = .003). Four additional HIV-infected adolescents became HBsAg-positive over the term of follow-up (incidence rate, 24.9/1000 person-years), despite a record of immunization against hepatitis B.

CONCLUSIONS

A substantial percentage of HIV-infected and HIV-uninfected Romanian adolescents have evidence of past or present HBV infection. In HIV-infected adolescents, the degree of immunosuppression is correlated with persistence of HBV replicative markers, even in the absence of clinical or biochemical signs of liver disease.

High prevalence of hepatitis B virus markers in romanian adolescents with human immunodeficiency virus infection

Background

We evaluated the frequency of hepatitis coinfection in Romanian adolescents who were diagnosed with human immunodeficiency virus (HIV) infection prior to 1995.

Methods

One hundred sixty-one adolescents (13–18 years of age) with symptomatic HIV infection, but without signs of hepatic dysfunction, and 356 age-matched, HIV-uninfected controls underwent laboratory testing for markers of parenterally acquired hepatitis virus infection.

Results

Seventy-eight percent of HIV-infected adolescents had markers of past or present hepatitis B virus (HBV) infection, as compared with 32% of controls (P = .0001). The prevalence of HBV replicative markers was more than 5-fold higher in HIV-infected adolescents as compared with controls: 43.4% vs 7.9% (P = .0001), respectively, for hepatitis B surface antigen (HBsAg); and 11.2% vs 2.2% (P = .0001), respectively, for hepatitis B e antigen (HBeAg). The prevalence of HBsAg chronic carriers and the presence of HBV replicative markers was significantly higher in patients with immunologically defined AIDS (CD4+ cell counts < 200 cells/mcL): 59.6% vs 34.6% (P = .02) for HBsAg and 22.8% vs 5.7%, (P = .002) for HBV DNA. After 1 year of follow-up, the proportion of those who cleared the HBeAg was considerably lower in severely immunosuppressed coinfected patients: 4.7% vs 37.1% (P = .003). Four additional HIV-infected adolescents became HBsAg-positive over the term of follow-up (incidence rate, 24.9/1000 person-years), despite a record of immunization against hepatitis B.

Conclusion

A substantial percentage of HIV-infected and HIV-uninfected Romanian adolescents have evidence of past or present HBV infection. In HIV-infected adolescents, the degree of immunosuppression is correlated with persistence of HBV replicative markers, even in the absence of clinical or biochemical signs of liver disease.

The comparison of different protocols for expansion of umbilical-cord blood hematopoietic stem cells

Hematopoiesis is maintained by the activity of multipotent stem cells, which have the dual capacity to self-renew and to differentiate into all of the blood cell lineages. The major challenge of stem cells based regenerative therapy is to expand ex vivo the primitive compartment to increase transplantable stem cells number. The present study was designed to evaluate several culture systems for in vitro maintenance of umbilical cord blood stem cells. The influences of different growth conditions such as stromal feeder layer, cytokines supplement and placental conditioned medium (PCM) have been evaluated over a relatively short period of time on CD34(+) cell expansion and maintenance of clonogenic progenitors. When cells were expanded on feeder layer in the presence of added cytokines and PCM on average a 2.96-fold increase of CD34(+)CD71(-) and a 3.13-fold increase of CD34(+)HLA-DR(-) was observed. The total number of colony forming cells (35 +/- 2.65) indicated also that the yield of clonogenic progenitors obtained with a combination of all factors was two folds higher than each of these factors alone and ten time above control (3.67 +/- 2.52). In conclusion, the results of our study clearly show that the ex vivo expansion of hematopoietic progenitor cells obtained from human umbilical cord blood is dependent on controlled experimental conditions, which might be helpful when designing culture systems for clinical applications.

The development of larger cells that spontaneously escape senescence--a step during the immortalization of a human cancer cell line

There are few information concerning the changes associated with the transition interval when slow growing, primary explanted human cancer cells are displaced by new selected faster growing cells and became an immortal cell line. In a previous paper (J. Cell. Mol. Med., 5: 49-59, 2001) we described the TV cell line derived from a laryngeal tumor which harbors human papillomavirus (HPV) gene sequences throughout more than sixty in vitro passages. In this paper we analyze the modifications observed during the crisis interval when significant amount of cells senesce but occasional cells acquire some mutations that make them immortal. Confocal microscopy analysis revealed the heterogeneity of the cells in terms of their size and nucleus/cell ratio. Proliferation capacity was assessed by flow cytometry analyzing DNA content and expression of transferrin receptor (CD71). We discussed the possibility that HPV genome sequences alleviate a proliferation block during the crisis growth arrest of human larynx carcinoma cell line and the possibility that the cells monitor their size and growth by measuring the levels of some protein whose synthesis is coupled to cell development.

Cloning and expression of the L1 major capsid protein of the human papillomavirus 18 in murine cells

Human papillomavirus (HPV) type 18 is strongly associated with the development of cervical cancer. Studies of a model system with animal papillomaviruses have demonstrated the importance of neutralizing antibodies in preventing papillomavirus-associated disease. The immune response to HPV is poorly understood, and there are non- standardized serological assays to identify HPV infections. In our study, the assessment of antibody responses against HPVs (previously hampered by the lack of viral source) was enabled by the expression of the L1 major capsid viral protein type 18 (HPV18) into L929 murine cells using the pTARGET mammalian expression vector system (MEVS). The cloning was validated by PCR with specific primers for the L1 gene, as well as by enzyme restriction and in situ hybridization. The evidence for the viral cloned gene expression was acquired by RT-PCR. Presence and antigenic properties of the recombinant L1 protein were shown using it as antigen in an indirect enzyme linked immunosorbent assay (ELISA) system. Significantly higher reactivity was noted when the sera samples were from persons infected with HPV18 as compared with the non-infected individuals but a moderately different reactivity was observed when the sera from patients infected with other HPV genotypes were tested. The results showed that the murine transfected cells could be used as antigen in order to detect the presence of the specific antibodies in HPV infected persons.

Ex vivo differentiation of umbilical cord blood progenitor cells in the presence of placental conditioned medium

Hematopoetic stem cells (HSC) are the progenitors for the lympho-hematopoietic system, with long lifespan and high proliferation potential. Transplantation of HSC from bone marrow or peripheral blood represents a standard therapy in severe hematological conditions. A possible alternative source of HSC is the umbilical cord blood, prepared by various separation procedures followed by expansion in cultures supplemented with hematopoietic growth factors. In order to check the effects of placental conditioned medium (PCM) from placental cells culture upon viability of HSC, we added plasma, PCM, dimetil sulfoxyde or hemin in HSC cultures. Flow cytometry or direct scoring of solid cultures using CD45+, CD34+, CD71+ and CD14+ fluorescent-labeled monoclonal antibodies evaluated the effects upon cell proliferation and colony forming ability of HSC cultures, versus controls. PCM produced the highest proliferation, followed by plasma, DMSO and hemin. PCM improved the survival time and maintained a higher proportion of immature cells. PCM stimulates the differentiation towards myeloid lineage progenitor cells (>90% being CD45+), increasing the percentage of CD14+, granulocites /monocytes precursors. It is highly suggestive that PCM contains growth factors or cytokines, which regulate the development of HSC. Characterization of these factors is in progress.

West nile virus surveillance in Romania: 1997-2000

In response to the 1996 West Nile (WN) fever epidemic that occurred in Bucharest and southeastern Romania, a surveillance program was established. The surveillance system detected 39 clinical human WN fever cases during the period 1997-2000: 14 cases in 1997, 5 cases in 1998, 7 cases in 1999, and 13 cases in 2000. Thirty-eight of the 39 case-patients lived in the greater Danube Valley of southern Romania, and 1 case-patient resided in the district of Vaslui, located on the Moldavian plateau. The estimated annual case incidence rate for the surveillance area during the period 1997-2000 was 0.95 cases per million residents. Thirty-four cases were serologically confirmed, and 5 cases were classified as probable. Twenty-four case-patients presented with clinical symptoms of meningitis (62%), 12 with meningoencephalitis (31%), 1 with encephalitis (3%), and 2 with febrile exanthema (5%). Five of the 39 cases were fatal (13%). Fourteen case-patients resided in rural areas, and 25 in urban and suburban areas, including 7 case-patients who resided in Bucharest. The ages of case-patients ranged from 8 to 76 years with a median age of 45 years. Twenty-four case-patients were males and 15 were females. Dates of onset of illness occurred from May 24 through September 25, with 82% of onset dates occurring in August and September. Limited entomological surveillance failed to detect WN virus. Retrospective sampling of domestic fowl in the vicinity of case-patient residences during the years 1997-2000 demonstrated seroprevalence rates of 7.8%-29%. Limited wild bird surveillance demonstrated seroprevalence rates of 5%-8%. The surveillance data suggest that WN virus persists focally for several years in poorly understood transmission cycles after sporadic introductions or that WN virus is introduced into Romania at relatively high rates, and persists seasonally in small foci.

Detection of human papillomavirus gene sequences in cell lines derived from laryngeal tumors

The role of Human Papillomaviruses (HPV) in laryngeal carcinomas has been studied with conflicting results. To evaluate the etiologic relationship between HPV infection and epithelial malignancy of the larynx we studied five laryngeal carcinoma cell lines obtained from patients undergoing surgery for laryngeal tumors. The paraffin embedded biopsy samples of the original tumor and different passages of the new established cell lines were investigated by PCR with consensus primers specific for HPV DNA. The findings indicate that HPV infection is associated with some larynx carcinomas. The positive association has been enhanced when a method of enrichment of epithelial cells from fresh tumor samples was used. All tumor cells enriched smears were positive for HPV DNA not only by PCR but also by in situ hybridization (ISH). Investigated by PCR, different passages of larynx tumor cell lines maintained expression of HPV DNA. At subsequent passages ISH gives constantly no signals suggesting a minimal amount of viral harbored sequences. In one cell line propagated more than 60 population doublings, the chromosomal frequency distribution shifted from modal number 46 at the 5(th) passage to 63 at the 60(th) passage. The mechanisms by which persistent HPV infection maintains continuous cell proliferation were discussed.

Evaluation of immunoglobulin M (IgM) and IgG enzyme immunoassays in serologic diagnosis of West Nile Virus infection

A unique urban encephalitis epidemic in Romania signaled the emergence of neurological infection due to West Nile (WN) virus as a novel public health threat in Eastern Europe and provided an opportunity to evaluate patterns of immunoglobulin G (IgG) and IgM reactivity in IgM capture and IgG enzyme-linked immunosorbent assays (ELISAs). WN virus infection was diagnosed serologically in 236 of 290 patients from whom acute serum or cerebrospinal fluid (CSF) samples were available. In 37% of serum samples and in 25% of CSF samples collected in the first week of illness, anti-WN virus IgM antibody was detected in the absence of virus-specific IgG. The switch to an IgG antibody response occurred after 4 to 5 days of illness and earlier in CSF than in serum. A specific humoral immune response was detected in the CSF before the serum in some patients for whom paired CSF and serum samples from the same day were available. IgM antibody in convalescent serum samples persisted beyond 2 months after the onset of illness in more than 50% of patients. ELISA optical density values and antibody concentrations were well correlated for both IgM and IgG immunoassays. Anti-WN virus IgM antibody in acute-phase samples did not cross-react significantly with flaviviruses in other antigenic groups.

Continued transmission of West Nile virus to humans in southeastern Romania, 1997-1998

After an epidemic of West Nile (WN) virus neurologic infections in southeastern Romania in 1996, human and animal surveillance were established to monitor continued transmission of the virus. During 1997 and 1998, neurologic infections were diagnosed serologically as WN encephalitis in 12 of 322 patients in 19 southeastern districts and in 1 of 75 Bucharest patients. In addition, amid a countrywide epidemic of measles, the etiology of the febrile exanthem in 2 of 180 investigated cases was determined serologically to be WN fever; 1 case was complicated by hepatitis. Sentinel chickens placed in Bucharest seroconverted to WN virus during the summer months, indicating their potential value in monitoring transmission. The continued occurrence of sporadic WN infections in southeastern Romania in consecutive years after the 1996 epidemic is consistent with local enzootic transmission of the virus.

Romanian HIV-AIDS epidemic after a decade of evolution

Situated in Southeastern Europe, with a surface of 237,500 km2 and a population of over 22 million, Romania was a special case in the evolution of global AIDS crisis. After the first reported case in a homosexual male in 1985, five years elapsed till the epidemiological investigations done in the Institute of Virology, Bucharest (1-4) provided strong evidence for what may represent the world's largest iatrogenic transmission of blood-borne pathogens in children. On the basis of Epidemiological Fact Sheet concerning Romania provided by UNAIDS/WHO Working Group on Global HIV/AIDS and STD Surveillance we offer a couple of graphics which are considered important for informed decision-making and planning at national and regional levels. We emphasize the lack of availability of many specific data both on epidemiological and socio-behavioral indicators. Structural collapse in Eastern Europe sets the scene for the rapid spread of HIV/AIDS among young people and the lack of information may contribute to an unexpected rebound of the epidemic.

Risk factors for West Nile virus infection and meningoencephalitis, Romania, 1996

In 1996, an epidemic of 393 cases of laboratory-confirmed West Nile meningoencephalitis occurred in southeast Romania, with widespread subclinical human infection. Two case-control studies were performed to identify risk factors for acquiring infection and for developing clinical meningoencephalitis after infection. Mosquitoes in the home were associated with infection (reported by 37 [97%] of 38 asymptomatically seropositive persons compared with 36 [72%] of 50 seronegative controls, P<.01) and, among apartment dwellers, flooded basements were a risk factor (reported by 15 [63%] of 24 seropositive persons vs. 11 [30%] of 37 seronegative controls, P=.01). Meningoencephalitis was not associated with hypertension or other underlying medical conditions but was associated with spending more time outdoors (meningoencephalitis patients and asymptomatically seropositive persons spent 8.0 and 3.5 h [medians] outdoors daily, respectively, P<.01). Disease prevention efforts should focus on eliminating peridomestic mosquito breeding sites and reducing peridomestic mosquito exposure.

An outbreak of aseptic meningitis due to ECHO 30 virus in Romania during the 1999 summer

Between April-September 1999 an unusually high number of acute aseptic meningitis was reported in six North Eastern counties of Romania. At the end of 1999 summer the epidemic area extended in South Romania including the Capital City Bucharest. The total number of cases surpassed 5500. The majority of confirmed cases were young children under 15 years of age. More than 1800 cases were registered in the same interval in the neighboring Republic of Moldavia. We report the isolation of ECHO 30 virus from 12 CSF samples of 52 tested on RD and human diploid cells. A small case control study identified high seroneutralization titers confirming a recent ECHO 30 infection in 74% of patient's samples and in 54% of samples from control children tested. The time spent outdoors and poor hygiene practices were prominent risk factors for transmission.

West Nile encephalitis epidemic in southeastern Romania

BACKGROUND

West Nile fever (WNF) is a mosquito-borne flavivirus infection endemic in Africa and Asia. In 1996, the first major WNF epidemic in Europe occurred in Romania, with a high rate of neurological infections. We investigated the epidemic to characterise transmission patterns in this novel setting and to determine its origin.

METHODS

Hospital-based surveillance identified patients admitted with acute aseptic meningitis and encephalitis in 40 Romanian districts, including Bucharest. Infection was confirmed with IgM capture and indirect IgG ELISAs. In October, 1996, we surveyed outpatients in Bucharest and seven other districts to estimate seroprevalence and to detect infected patients not admitted to hospital. We also measured the rates of infection and seropositivity in mosquitoes and birds, respectively.

RESULTS

Between July 15 and Oct 12, we identified 393 patients with serologically confirmed or probable WNF infection, of whom 352 had acute central-nervous-system infections. 17 patients older than 50 years died. Fatality/case ratio and disease incidence increased with age. The outbreak was confined to 14 districts in the lower Danube valley and Bucharest (attack rate 12.4/100000 people) with a seroprevalence of 4.1%. The number of mild cases could not be estimated. WN virus was recovered from Culex pipiens mosquitoes, the most likely vector, and antibodies to WN virus were found in 41% of domestic fowl.

INTERPRETATION

The epidemic in Bucharest reflected increased regional WNF transmission in 1996. Epidemics of Cx pipiens-borne WNF could occur in other European cities with conditions conducive to transmission.

Low rates of seroconversion after hepatitis B vaccination in orphanges with high prevalence of virus carriers

A serosurvey of Hepatitis B infection markers was conducted in two orphanages that adhered to Hepatitis B vaccination policy. In spite of comparable sizes (80-90 children per facility), housing conditions and infection control practices, the level of HbsAg endemicity was different in each unit in direct relation with the mean age of the children. The prevalence of HbsAg carriers and the interval spent in collectivity strongly affect the seroconversion rate after HB vaccination. Other elements that can explain the low seroconversion rate were: the proportion on fully vaccinated children, the number of vaccine administered doses and the delayed age at which childhood immunization schedule was initiated. In order to increase the protective antibody response, booster doses were administered to a limited number of nonseroconvertors or to children with a nonprotective level of anti-HBs antibody (< 10 UI). This intervention provides evidence of prompt rising in antibody titers, comparable with titers found in children with wild infection.

"Trial moves rapidly on, when the judge has determined the sentence beforehand" (W. Scott: Ivanhoe, 36) or pitfalls in serosurvey of anti-hepatitis C antibody in children

Hepatitis C is and will be a major public health concern. Confirmed infections were reported from all Romanian counties but important differences between regions raise several explanations. Differences may reflect the different levels of testing, the performances of laboratories in confirming initially reactive samples or the risk factors higher prevalence. We have suggested that the prevalence of anti HCV infections can be a surrogate marker for the quality of parenteral medical or paramedical interventions. Present report identified additional problems in the surveillance of HCV infection in children. We screened 1787 samples from children hosted in orphanages (children under three years old) or in preschool children institutions (between 3-7 years old). We detected 31 repeatedly reactive samples with two EIA screening kits but confirmed only 8 in WB anti HCV. Four confirmed samples come from children under four months old suggesting maternally transmitted antibodies. In highly endemic area, many infants have maternally derived antibodies and the wane of reactivity comes with age above 12 months. Therefore, the prevalence of anti HCV antibody in infants reflects the prevalence in adult population. Confirmatory tests are mandatory for the serosurvey in children. More frequent than adults samples, children EIA reactive samples give indeterminate or negative Western Blot profiles. Only the viral load evaluation can confirm those samples as false positive or, on the contrary, samples at the beginning of seroconversion.

Assessment of the anti-hepatitis B vaccination efficacy in high risk children

In October 1995, The Ministry of Health has initiated the national immunization program of newborns against hepatitis B. Owing to the frequency of asymptomatic Hepatitis B clinical forms in children, as well as the deficiencies in the surveillance system, the assessment of the vaccination efficacy can be performed objectively only by the detection of the prevalence of anti HBs antibodies in children to whom the complete three doses of immunization schedule have been administered (at 0, 2 and 6 months of age). We report in this study the results of a seroprevalence research carried out on a group of 272 children from orphanages who have been vaccinated. A protective anti HBs titer (> 10 mIU) was recorded only in 66.3% of cases; other 10 samples contained antibodies at a titer lower than the protective level. In the 80 children without seroconversion the presence of anti HBc antibodies (marker for the natural infection) was investigated. 30% of the seronegative children have anti HBc antibodies from which 54.2% have also HbsAg. Significant differences were recorded in the seroconversion level and in the geometric mean of titers between the various units in which sera were collected. In four orphanages (district Arad, Jassy, Sibiu and Teleorman) the seroconversion exceeded 90%, in 5 orphanages it was over 80% and in the others it ranged from 30% to 70%. The lowest seroconversions were recorded in the orphanages in Bucharest, Botoşani, Galaţi and Olt. The possible causes of the low immunogenicity are analyzed: non-vaccination or incomplete vaccination; low immunoreactivity of children, many of whom are premature; high HbsAg carriage rate among the mother's etc. Although the evolution of the post vaccinal seroconversion is not a routine practice in the appraisement of Hepatitis B vaccine immunogenicity, our results require the extension of the study in order to adopt the most effective vaccinal strategy.

A high number of severe neurologic clinical forms during an epidemic of West Nile virus infection

The serologic confirmation of more than 800 cases hospitalized during the viral meningoencephalitis epidemic caused by the West Nile virus (WNV) that affected the South-East of Romania during the summer of 1996 consolidated the case definition in over 80% of the patients admitted to the hospital with neurological impairments. Other clinical forms of the WN infection were reported only scarcely during the epidemic and were seroconfirmed at a lower rate (60%). IgM capture ELISA (MAC-ELISA) is a test of choice for the rapid diagnosis. The major advantage of MAC-ELISA procedure is the high probability of accurate diagnosis of WN infection when the test is performed only with acute serum or cerebrospinal fluid (CSF) specimens obtained while the patient is still hospitalized. Rapid diagnosis by MAC-ELISA is important for the institution of public health control, but the results obtained have also some predictive values. We report the serological patterns of 65 pairs of CSF and serum samples collected in the early days of neuroinfection for diagnostic purposes. An unexpected onset of the intrathecal specific humoral immune response before serum immunoglobulins synthesis was recorded in 25% of cases. For 14 patients with intrathecal onset of IgM synthesis, their records evaluated retrospectively showed a severe evolution. The presence of only IgM antibodies in CSF is a characteristic which matched with other laboratory variables described which predict poor evolution in viral encephalitis: pleocytosis, elevated protein concentration in CSF (> 100 mg per deciliter), hyponatremia (< 130 mmol per liter).

Serological profile assessment of the infection with hepatitis C virus (HCV) in haemophiliacs and thalassemic patients

Polytransfused patients represent a major risk group for hepatitis C (HCV) acquirement. Haemophiliacs and thalassemic patients treated with virus contaminated blood or blood derivatives frequently exhibit anti-HCV antibodies and signs of chronic hepatitis. The serological profile for the HCV infection was investigated in 13 haemophiliacs, 18 cases of thalassemia and in 14 polytransfused patients affected by other diseases. The presence of anti-HCV antibodies was detected by means of the ORTHO HCV 3.0 ELISA kit and confirmed by Western-blot Murex. The serotyping used synthetic peptides mimicking the immunodominant epitopes in the NS4 region, characteristic of each of the six HCV genotypes in an ELISA blocking reaction (Murex). Serotype 1 was prevalent (51.1%), while serotype 2 was detected in 13.3% of patients, with a higher frequency in thalassemia cases. The remaining samples were multireactive, and serotype 3 alone was not detected. The profile of Western-blot bands was distinct for the monoreactive samples belonging to serotype 1 or 2. The analysis of the multireactive samples in young (thalassemic, age mean 15.17 +/- 6.5) and aged patients (haemophiliacs, age mean 32.64 +/- 13.5) allows us to suggest a different succession of reinfection acquirements. The infection with one of the subtypes does not confer protection against the reinfection with others. However, a certain attenuation of the symptomatology is obvious in the case of reinfections, indicating the existence of crossantigenic reactivities which contribute to protection. This protection is more evident in the case of primary infection with type 2 and is partially due to antigens coded by the NS4 genomic segment.

Immunological disorders of increased severity in children with AIDS associated with hepatitis B and C infections

Two groups of children were set up: children infected with HIV and hepatitis viruses and children infected with HIV, but not with hepatitis viruses, too. The immunological aspects investigated referred to the Ig serum value, the absolute number of T CD4 lymphocytes and the T CD4/T CD8 ratio. The subjects of the first group (in whom hepatitis markers were present) displayed increased IgA and IgM values at a higher rate than those of the second group (54.87% against 32%, 83.3% against 53%), as well as a lowering below 300/ml of the number of T CD4 lymphocytes (50% against 29.4%). On the other hand, increased IgG levels and values below 0.8 of the T CD4/T CD8 ratio were found at similar rates in the two groups of children (77.4% against 80% and 70.5% against 70% respectively). By means of the data obtained, the authors try to point out one of the ways by which hepatitis viruses, considered as a potential cofactor in the AIDS development, contribute to the course of this disease, namely by intensifying the immunological disorders.

Nucleic acid vaccines

Direct DNA delivery in vivo can be utilized for the production of proteins as well as for the induction of specific cellular and hunoral immune response against a large number of viral pathogens (influenza, hepatitis B, HIV, etc.). Immunogenic levels of gene expression can be achieved in vivo or, alternatively, facilitated DNA inoculation methods have been described for efficient induction of protective immunity. DNA immunization of a number of viral target proteins has been accomplished in a variety of species including non human primates. Our review focuses on the use of this novel technology for the prevention of human retroviruses infections. Some safety considerations for viral nucleic acid vaccines and regulatory requirements are also discussed.

Serological diagnosis of chronic viral hepatitis

Chronic viral hepatitis must be distinguished from other chronic liver disorders. The clinical picture associated with typical biochemical findings provides no definite information about the causative agent. An important factor, both for the patient and for the individuals in contact with him, is the evaluation of his infectivity. From 172 chronic hepatitis disorders the serological diagnosis confirmed the viral etiology in 120 patients (69.7%). HBsAg was present in 33.7% (with HBeAg in 5%), anti-HCV antibodies 22.6% and markers for both viruses in 13.4% of cases. The HCV etiology was more frequently found in chronic hepatitis (44.9%) in liver cirrhosis (50.7%). The smaller number of patients displaying simultaneously anti-HBs and anti HCV antibodies did not confirm the recent suggestions that HCV would be the most important hepatotropic virus which enhances HBsAg clearance in chronic hepatitis.

Studies on the intermolecular forces involved in the antibody-antigen interactions, using V3 synthetic peptides and sera from HIV1 seropositive patients

The nature of physical forces responsible for the antibody-antigen (Ab-Ag) reaction was analyzed in an original system, represented by synthetic peptides derived from the V3 consensus sequences of some HIV1 subtypes gp 120 and HIV1 positive human serum. For locating antigenic determines, flexibility, hydrophilicity and hydrophobicity profiles of the V3 peptides were analysed. The hydrophilicity indicates that V3 apex borders are involved in the first stage of the reaction. The flexibility and hydrophobicity suggest that the apex of the V3 loop (GPGR/Q) is involved in the stabilization of the complex by hydrophobic interactions. Further, we followed up the influence of the dielectric constant and of the pH upon the forces established between Ab and Ag. Modifications in the dielectric constant and pH reveal a significant contribution of electrostatic and van der Waals forces in securing the intermolecular complementarity. D2O produces the highest augmentation of the antibody affinity for the most hydrophilic peptides, while a very slight one was recorded for the most hydrophobic sequence. A high affinity of antibodies for the peptides MN, R and Z was registered at an acid pH, when their His residue was protonated. On the contrary, no influence was recorded in the case of the peptide A, which does not contain any His residue.

Syncytium forming capacity of HIV 1 strains in inhibited by pretreatment of CD4 expressing cells with 3'-azido-3'-deoxythymidine but not by alpha interferon

3'azido-3'deoxythymidine (AZT) inhibits the ability of uninfected CD4 expressing cells to participate in syncytium formation, when cocultured with cells chronically infected with human immunodeficiency virus type 1 (HIV 1). The inhibition of giant cells formation is similar, irrespective of the AZT-sensitive or resistant phenotype of the HIV1 strains. The effect on syncytium formation occurs when the uninfected target cells are pretreated with AZT, the therapeutic index varying between 290 (CEMss, H9 and > 2000 (HeLa CD4 beta gal). The syncytium reducing effect of AZT is an additional antiviral property, distinct from the inhibition of HIV replication. The HIV 1 phenotype (AZT sensitive or resistant) determines differences both in the morphology of syncytia and in the kinetics of syncytium formation. Pretreatment of the target cells with alpha interferon (125-2000 UI/ml) either alone or in combination with AZT, has no effect on the ability of these cells to participate in syncytium formation, probably owing to the basal IFN synthesis in the system.

CD 26--to be or not to be a cofactor for CD 4 receptor of human immunodeficiency viruses

Earlier work has shown that HIV binding to CD 4 is necessary, but apparently not sufficient, for viral entry into cells. Several molecules have been proposed as potential candidates for coreceptors in HIV infection. Remarkable attention and criticism was raised by the report of Hovanessian group from Pasteur Institute, France, which claimed the role of CD 26, an enzyme also known as dipeptidyl peptidase IV, as cofactor in HIV entry and HIV infection. Present review mentions some reports which support or reject this hypothesis.

Considerations about the prophylactic role of T cell vaccination in HIV infection

The AIDS epidemic in Romania has properties that are both common to countries of Eastern Europe and unique to Romania. The unique aspects include the large number of cases in children infected parenterally and a relatively low but steadily increasing number of HIV infected adults. Other groups of children and adults were also exposed at risk to acquire HIV by transfusion with unscreened blood or by multiple parenteral treatments with potentially contaminated needles. Our hypothesis was that a substantial number of people in area of high endemicity was "silently" infected but did not undergo specific immune response or clinical signs. In an attempt to explore the possibility that immunization with autologous proteins (consequence of multiple transfusions) can play a role in the protection from HIV infection or in slowing down the progression of disease, we compared the incidence of autoantibodies (anti-nuclear, smooth muscle and anti-HEp-2) in a group of long survivors children with AIDS, in HIV infected children with rapid evolution and in adults at risk for parenteral acquisition of blood borne viral disease. We analyzed also the incidence of some blood borne viral infections and the presence of anti-HLA antibodies in the same groups of patients. Our results do not support the suggestion that HIV infection or AIDS can be prevented, respectively, delayed by T-cell vaccination.

Preliminary results of HIV screening in sentinel facilities in Romania

In the first months of 1994, 393 patients (random consecutive clinic attenders) from three sentinel clinics were tested for anti-V3 loop antibodies in ELISA with a branched synthetic peptide reproducing eight copies of full V3 sequence. Compared with a commercial HIV 1/2 ELISA kit the sensitivity of anti-V3 assay was 97.6% and the specificity 89.7%. The seroprevalence in women attending prenatal clinic was 7.54% and in children with multiple hospitalization record, 3.82%. Both heterosexual and parenteral transmission through unsafe medical practices fuel actual AIDS epidemic in Romania.

Neuroophthalmological examination in children with AIDS

Evaluation of HIV disease status includes physical examination (anthropomorphic measurements, neurological assessment, etc.) and laboratory examination. Consideration should be given to changes from baseline values, age adjusted normal values and the rapidity of changes. Here we compare results of neuroophthalmologic assessment with Western Blo (WB) profiles in cerebrospinal fluids (CSF) of 54 children with AIDS. Children were classified by Denver Developmental Screening Test (DDST) administration in encephalopathy positive (n = 44) and encephalopathy negative (n = 10) groups. Neuroophthalmological examination which included nine items with good test-retest reliability showed that two of them (nystagmus on following and visual memory impairment) appeared early in the encephalopathy free group and correlated with the loss of some gag band in Western Blot (lower gag score). No correlation was however, found with respect to p24 antigen level in cerebrospinal fluid, a marker which reflects CNS viral load.

Relevance of the reactivity of HIV 1 positive sera with synthetic peptides for understanding antigenic differences between circulating strains

Several problems have arisen concerning the detection methodology of sources and chains of HIV transmission based on molecular and antigenic relatedness of HIV isolates. Great progress in mapping virus genome or provirus, especially in identifying the changes in the env gene provides interesting data for molecular epidemiology. We address the same problem by the investigation of the reactivity of sera from HIV 1 seropositive children with two panels of synthetic peptides mimicking immunoreactive fragment of HIV1 glycoproteins in solid phase EIA. The samples proceed from two distinct settings: an orphanage in which nosocomial transmission was highly suspected and from different hospitals caring for HIV infected children. The synthetic peptides have sequences which reproduce two target regions: one in the principal neutralization domain of gp 120 (V3 loop) and the other at the COOH end of gp 41. Our results indicate that minimal differences in aminoacids flanking central conserved GPGRA region in V3 loop of gp 120 evidence strain specific antibodies while the COOH end of gp 41 reveals antibodies which link HIV 1 strains in a broad fashion. Sera from HIV infected children collected in different settings recognize the same synthetic peptides panel with distinct frequencies suggesting circulation of different antigenic strains.

[Seroprevalence of hepatitis C virus among the multiply transfused]

A study was conducted on 61 polytransfused patients, 24 patients submitted to long lasting parenteral treatments, 116 blood donors and 132 controls. Immuno-enzymatic tests were used for detection of antibodies against hepatitis C virus (HCV). They were found in 56 (91.8%) out of the 61 polytransfused patients, in 5 (4.3%) of the donors, in 5 (20.8%) of the patients with multiple treatments and in 5 (3.7%) controls. The VHB markers were detected at variable rates in all investigated groups. The high rate of seropositivity indicates that hepatitis C is becoming an important public health problem in Romania.

[A seroprevalence study of the hepatitis C virus among multiply transfused patients]

A study was conducted on 61 polytransfused patients, 24 patients submitted to long lasting parenteral treatments, 116 blood donors and 132 controls. Immuno-enzymatic tests were used for detection of antibodies against hepatitis C virus (HCV). They were found in 56 (91.8%) out of the 61 polytransfused patients, in 5 (4.3%) of the donors, in 5 (20.8%) of the patients with multiple treatments and in 5 (3.7%) controls. The VHB markers were detected at variable rates in all investigated groups. The high rate of seropositivity indicates that hepatitis C is becoming an important public health problem in Romania.

The evolution of hepatitis B virus infection in children with symptomatic AIDS

Hepatitis B virus (HBV) markers were determined in 80 children under 5 years of age with HIV symptomatic infection. Because of high carrier rate of hepatitis B virus in Romania we investigated as control a group of age matched 36 HIV negative children offsprings of HBsAg carrier mothers. Serological and epidemiological investigations in families of HIV infected children support horizontal nosocomial and not vertical transmission for HIV in contrast with HBV whose perinatal transmission can not be excluded. Concerning the probable route of HBV infection both groups of children seem to have a comparable risk for parenteral, contact-associated or maternal-neonatal transmission. HBsAg was detected in 76.25% HIV positive subjects and in 13.9% of control (P = 0.05). From all serum samples tested, only 12, all from the control group, did not present any markers of past or current HBV infection. Two serum markers have been used as an index of active HBV replication: HBe antigen detection and HBs antigen quantification in one or paired serum specimens. HBeAg was detectable in 20% of HIV infected children and only in 2.8% controls (P = 0.05). Almost all HBeAg positive patients have higher values for HBs antigenemia. HBsAg concentrations well above the assay cut off value (sample/cut off ratio > 15) were generally representative for HIV infected children (54% versus 5.6% in controls). The prevalence of hepatitis Delta markers and anti-HCV antibodies was not significantly higher in HIV infected children in spite of the fact that they are potentially exposed to a wider range of antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological roles of HIV Nef proteins. A minireview

The nef gene, its protein products and diverse mechanisms by which HIV pathogenicity is nef-mediated in vivo and in vitro explain the huge amount of works on this topic. Until now the following functional roles have been assigned for nef: 1. downregulation of virus replication; 2. GTP binding and GTPase activities; 3. modulation of cytoplasmic signalling; and 4. cellular (CD4 and IL-2) gene regulation. Many reports which demonstrate the possible functions of nef in viral replication and in development of AIDS have been refuted by other scientists who failed to confirm some biological activities. Host immune response against nef proteins has been claimed as an early diagnosis marker or to be involved in disease progression. Also, nef proteins have been involved in blocking of HLA antigens, in superantigen production or in crossreactivity with some cellular antigens. The role of nef is a complex one, important in establishing and maintaining viral latency in vivo and regulating virus replication in vitro.

[The knowledge and attitudes of medical students in their 2d year about AIDS]

This study had two specific aims: determining the level of knowledge about AIDS acquired through the courses on this subject; analysing the students' attitude towards the disease, with respect to different aspects related to the future professional risk. For this purpose, a questionnaire was made up and from the answers a data base was set up, processed and stored for further studies. We analysed to which extent the students are acquainted with the routes of transmission of HIV infection, with the groups of risk and with the groups of ages exposed to contagion in Romania. We were interested in whether the students recognize the clinical signs of the disease, the diagnosis methods and the specific medicines used. We studied to which extent the students consider the routine HIV diagnosis necessary for all hospitalised patients, for foreigners residing in Romania, for Romanians working abroad, as well as for couples before marriage. In order to have a clear image on the students' opinion about the risk of getting the disease in general as well as on their fears concerning the professional risk of infection, several questions in this regard were included in the questionnaire. Another important aspect of the study consists in estimating the degree to which the knowledge acquired through the courses make the students able to offer in their turn useful and credible information to their family, friends or strangers. The students' perception of AIDS is mainly determined by the risk of sexual contamination, while the control measures regarding the interruption of the other ways are underestimated.

HCV seroprevalence in dialysis patients, their relatives and medical staff

HCV infection has emerged as a significant problem for both dialysis patients and medical staff. We report the data found in a dialysis center in Bucharest for hepatitis B, C and HIV infections. Single random samples collected from 133 dialysis patients give a seroprevalence of 91.7% for HCV antibodies in contrast with the absence of seropositives between medical staff members. To assess the relative risk for HCV transmission by sexual or casual contacts we investigated also 15 samples from the relatives of patients. One spouse and the child were found positive. The differences in the epidemiology of B and C hepatitis are discussed.