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.