Willingness to participate in HIV vaccine trials among a sample of men who have sex with men, with and without a history of commercial sex, Rio de Janeiro, Brazil.

The study objective was to assess willingness of men who have sex with men (MSM) enrolled in a vaccine preparedness study ('Projeto Rio') to participate in phase III anti-HIV/AIDS vaccine trials. Overall, 57% of Projeto Rio participants stated they would participate in a putative vaccine trial. MSM who reported commercial sex work were significantly (p < 0.05) more likely to engage in risky behaviours than others. In bivariate analysis, commercial sex workers (CSWs) were significantly (p < 0.05) more likely than non-commercial sex workers (NCSWs) to be willing to participate in vaccine trials (62.6% versus 51.4%). Among those willing, CSWs reported significantly more often (p < 0.05) (50.5%) than NCSWs (38.0%) that they would enroll to protect themselves from HIV. In multivariate analyses, variables associated with willingness to participate (WTP) were lower educational level, positive serology for syphilis, and 'engagement, under the influence of alcohol, in risky sexual practices that would normally be avoided', but not commercial sex work. The potential enrollment in vaccine trials of MSM CWSs, as well as participants of low socio-economic status and high risk, seems thus to be possible.

Biological characterization and chemokine receptor usage of HIV type 1 isolates prevalent in Brazil.

The human immunodeficiency virus type 1 (HIV-1), the etiological agent of the acquired immunodeficiency syndrome (AIDS), shows a variety of biological properties, which may constitute an obstacle to development of effective vaccines or antiretroviral therapy. To characterize Brazilian strains of HIV-1, we studied 24 viruses isolated from blood samples of HIV-1-positive patients from different regions of the country. To examine the cell tropism and the virus ability to form syncytia, primary macrophages and the CD4+ T cell line MT-2 were infected with these viruses. We found that 22 isolates replicated well in macrophages (macrophage-tropic isolates), 2 infected only MT-2 cells (T cell line tropic variants), while 6 of them grew in both cells. We found 8 syncytium-inducing (SI) and 16 non-SI (NSI) isolates. Continuous cultures of 18 isolates were established in the CCR5+/CXCR4+ cell line PM-1, and SI/NSI features of these viruses were confirmed by cell fusion assay with uninfected CD4+ T cell lines (PM-1, MT-2, H9, and SUP-T1). The coreceptor usage of 18 isolates was investigated by infecting U87 cells transfected with CD4 and chemokine receptors, and we found that 11 isolates infected only CCR5+ cells, 3 only CXCR4+ cells, whereas 4 used both coreceptors. We also observed that X4 isolates were more sensitive to neutralization by dextran sulfate than R5 or R5X4 viruses. Our findings show that the Brazilian isolates are phenotypically similar to those prevalent in other regions, which could mean that therapeutic strategies based on HIV-1 phenotypic properties would be efficient in Brazil, as in other countries.

Perception of vulnerability to HIV infection in a cohort of homosexual/bisexual men in Rio de Janeiro, Brazil. Oswaldo Cruz Foundation STD/HIV Prevention Group.

The present study addresses sociodemographic characteristics, knowledge and attitudes regarding HIV/AIDS, as well as risk behaviour and perception of vulnerability to HIV infection, in the first 295 homosexual and bisexual volunteers (excluding male commercial sex workers and transvestites) taking part in a cohort study in Rio de Janeiro. The sample has a higher socio-economic level than the remainder of the cohort, and than comparable strata of the general population, and a sound knowledge about how to protect themselves against HIV infection. In addition, an association between perception of vulnerability to infection and the practice of unprotected anal sex was observed. An association was also observed between higher levels of formal education and perception of vulnerability; however no association was found with markers for past and recent exposure to sexually transmitted infections (hepatitis B, HbsAG and syphilis). The results of the present study suggest that knowledge and awareness of risk do not easily translate into behaviour change, since significant proportions of the cohort continue to practise unprotected sex with both principal and casual partners, despite their awareness of HIV infection risks as well as preventive measures.

The Rio de Janeiro HIV vaccine site-II. Recruitment strategies and socio-demographic data of a HIV negative homosexual and bisexual male cohort in Rio de Janeiro, Brazil.

The initial effort of the Brazilian Ministry of Health to be an active partner in the world effort in the preparation of future accurate human immune deficiency virus (HIV) efficacy trials was the establishment of a multi-centered cohort of homosexual and bisexual men. An open cohort was established to determine the HIV incidence and the socio-behavioral aspects involved in Rio de Janeiro. A total of 318 potential participants, originated from multiple sources (health units, public information, snowball recruitment), were screened and recruitment became effective through the direct involvement of target communities (with the support of Non Governmental Organizations) and the population. Among this group, seropositivity for sexually transmitted diseases was high with 23, 32 and 46% for HIV, syphilis and hepatitis B, respectively. The socio-demographic data from the first 200 participants of this HIV negative cohort suggests that the cohort volunteers are an appropriate sample of the general male population of the State of Rio de Janeiro.

Acute respiratory infections in children living in two low income communities of Rio de Janeiro, Brazil.

Community studies of non-hospitalized children are essential to obtain a more thorough understanding of acute respiratory infections (ARI) and provide important information for public health authorities. This study identified a total ARI incidence rate (IR) of 4.5 per 100 child-weeks at risk and 0.78 for lower respiratory tract infections (LRI). Disease duration averaged less than one week and produced a total time ill with ARI of 5.8% and for LRI 1.2%. No clear seasonal variation was observed, the sex-specific IR showed a higher proportion of boys becoming ill with ARI and LRI and the peak age-specific IR occurred in infants of 6-11 months. Correlation with risk factors of the child (breastfeeding, vaccination, diarrheal disease, undernourishment) and the environment (crowding, living conditions, maternal age and education) showed marginal increases in the rate ratios, making it difficult to propose clear-cuts targets for action to lower the ARI and LRI morbidity. The importance of an integral maternal-child health care program and public education in the early recognition of LRI is discussed.

Etiology of acute respiratory tract infections among children in a combined community and hospital study in Rio de Janeiro.

We reviewed data collected between January 1987 and December 1989 on the etiology of acute respiratory infections (ARI) among 827 children in two low-income communities and a hospital in Rio de Janeiro. Respiratory syncytial virus was identified in 38% of cases of ARI, influenza A virus in 1%, parainfluenza 3 virus in 1%, and multiple viruses in 1%. Respiratory syncytial virus was most prevalent among hospitalized children, with seasonal increases in the late fall and winter. The principal bacterial pathogens were Staphylococcus aureus, gram-negative bacteria, Streptococcus pneumoniae, and alpha-hemolytic streptococci. Specimens that were most often positive were pleural fluid (46%) and specimens from other normally sterile sites (24%); normally sterile sites included the CSF, trachea, and lungs. Urine counterimmunoelectrophoresis for S. pneumoniae and Haemophilus influenzae polysaccharide antigens was positive in 3% and 2% of cases, respectively. Pharyngeal cultures yielded low numbers of S. pneumoniae and H. influenzae organisms and higher numbers of gram-negative bacteria. This study demonstrates the high incidence of ARI (4.5 cases per 100 child-weeks) among children in Rio de Janeiro and the high morbidity associated with the illness (ARI is responsible for 25%-50% of all pediatric hospitalizations) and the fact that continued attention must be paid to both viral and bacterial agents of ARI.

Longitudinal study of acute respiratory diseases in Rio de Janeiro: occurrence of respiratory viruses during four consecutive years

Investigamos, durante um periodo de 4 anos (1982 a 1985), a ocorrencia de virus em secrecoes de nasofaringe coletadas de criancas com menos de 5 anos de idade apresentando quadro clinico de infeccao respiratoria aguda (IRA), residentes na cidade do Rio de Janeiro. Foram encontrados todos os virus conhecidos como associados a IRA, com excessao do virus influenza C e parainfluenza 1, 2 e 4. Virus foram isolados mais frequentemente de criancas internadas em salas de emergencia e enfermarias que daquelas atendidas em ambulatorio. Este fato esta claramente relacionado com a alta incidencia do virus sincicial respiratorio (RSV) nos casos mais severos de IRA. Especimes positivos para RSV aparecem principalmente durante o outono, nos 4 anos consecutivos, indicando uma ocorrencia sazonal. As salas de emergencias sao a melhor fonte de dados para vigilancia do RSV, onde um aumento no numero de casos positivos corresponde a um aumento no numero total de casos de IRA internados. Os adenovirus ocupam o segundo lugar entre os virus frequentemente isolados, sendo predominante os sorotipos 1, 2 e 7. Embora em menor numero os virus influenza e parainfluenza tipo 3 tambem sao encontrados. Virus influenza A foram isolados igualmente em criancas internadas em enfermarias, salas de emergencia e nos pacientes atendidos em...

Longitudinal study of acute respiratory diseases in Rio de Janeiro: occurrence of respiratory viruses during four consecutive years.

The occurrence of different viruses in nasopharyngeal secretions from children less than 5 years old with acute respiratory infections (ARI) was investigated over a period of 4 years (1982-1985) in Rio de Janeiro. Of the viruses known to be associated with ARI, all but influenza C and parainfluenza types 1, 2 and 4 were found. Viruses were found more frequently in children attending emergency or pediatric wards than in outpatients. This was clearly related to the high incidence of respiratory syncytial virus (RSV) in the more severe cases of ARI. RSV positive specimens appeared mainly during the fall, over four consecutive years, showing a clear seasonal occurrence of this virus. Emergency wards provide the best source of data for RSV surveillance, showing sharp increase in the number of positive cases coinciding with increased incidence of ARI cases. Adenovirus were the second most frequent viruses isolated and among these serotypes 1, 2 and 7 were predominant. Influenza virus and parainfluenza virus type 3 were next in frequency. Influenza A virus were isolated with equal frequency in outpatient departments, emergency and pediatric wards. Influenza B was more frequent among outpatients. Parainfluenza type 3 caused outbreaks in the shanty-town population annually during the late winter or spring and were isolated mainly from outpatients. Herpesvirus, enterovirus and rhinovirus were found less frequently. Other viruses than RSV and parainfluenza type 3 did not show a clear seasonal incidence.

A serological investigation of rotavirus infections in a shanty town population in Rio de Janeiro.

The presence of antibodies against rotavirus was investigated by enzyme immunosorbent assay (ELISA) in two distinct groups of children living in a shanty town in Rio de Janeiro. One hundred and thirty six plasma samples were randomly collected from children of 0 to 33 months (first group) and 255 serum samples were collected from other 85 children at ages of 2, 6 and 9 months (second group). A high percentage of antibodies were found in the newborn children and this rate decreased progressively until the age of 11 months, after which it increased again. At the age of 7 months, geometric mean antibody titers increased indicating that infection had occurred.

Influenza surveillance in Rio de Janeiro between 1980-1981: a virological and serological study.

Laboratory surveillance of Influenza has shown a low virus activity in Rio de Janeiro during 1980 and 1981. A few influenza A (H3N2) viruses were isolated in both years during the winter months. Serological investigations showed that this subtype has circulated mostly among children under 10 years of age. No H1N1 virus was isolated but an increase in the proportion of adults with antibody to this virus was noted in sera collected in 1981. Influenza B virus was isolated from children in the spring of 1981 and again an increase was noted in the proportion of adults with antibody to this virus.

Comparison of polyacrylamide gel electrophoresis (PAGE), immuno-electron microscopy (IEM) and enzyme immunoassay (EIA) for the rapid diagnosis of rotavirus infection in children.

Detection of rotavirus RNA by polyacrylamide gel electrophoresis (PAGE) proved to be a highly sensitive and rapid diagnostic test. A comparison of this assay with immuno-electron microscopy (IEM) and enzyme immunoassay (EIA) in 245 faeces from children with gastroenteritis revealed complete agreement between the three assays in 238 (97.14%) samples. Among 75 samples positive in at least one of the three assays, negative results were observed in 5 (6.48%) by PAGE, in 6 (6.76%) by EIA and in none by IEM. Silver staining greatly increased the sensitivity of the PAGE assay. We conclude that although IEM remains the most sensitive and rapid rotavirus diagnostic assay, the PAGE technique has many advantages in its favour, including the non-requirement of expensive equipment, the use of only chemically defined reagents and the capacity to distinguish virus subgroup and variants and to detect non-crossreactive rotaviruses which are missed in serological assays.

Viral etiology of acute respiratory diseases in Rio de Janeiro: first two years of a longitudinal study.

A two-year study was undertaken to establish the incidence and possible viral etiology of acute respiratory diseases among the child population of a shanty town in Rio de Janeiro, Brazil. The results demonstrated that nearly half of all the illnesses seen were respiratory infections, 10% of them affecting the lower respiratory tract. Viruses were isolated from 20% of the throat swabs collected. Of the viruses identified, 47% were adenoviruses, 25% were enteroviruses, 9% were influenza A, 8% herpes simplex, 7% parainfluenza, 3% respiratory syncytial and 1% influenza B viruses.

An atypical rotavirus detected in a child with gastroenteritis in Rio de Janeiro, Brazil.

Particulas morfologicamente identicas a rotavirus foram encontradas nas fezes de uma crianca de dois meses com gastroenterite. Analise do genoma viral por eletroforese em gel de poliacrilamida revelou 10 faixas (provavelmente 11 segmentos) de RNA, algumas das quais diferem em velocidade de migracao das observadas na grande maioria de rotavirus de hospedeiros humanos e de diversas especies de animais. O virus nao foi revelado por um ensaio imuno-enzimatico de alta sensibilidade, o que sugere a ausencia do antigeno de grupo que da reacoes cruzadas entre a maioria dos rotavirus. O virus descrito no presente trabalho foi o unico com tal comportamento entre 230 amostras analisadas por nos desde 1979. A relevancia de existencia de rotavirus nao relacionados antigenicamente a outros membros do grupo e discutida

Comparasion of polyacrylamide gel electrophoresis (PAGE), immuno-electron microscopy (IEM) and enzyme immunoassay (EIA) for the rapid diagnosis of rotavirus infection in children.

A evidenciacao da presenca de acido ribonucleico (ARN) viral por eletroforese em gel de policrilamida (EGPA) foi comprovada como um metodo altamente sensivel e rapido para o diagnostico de infeccoes por rotavirus. Uma comparacao desta prova com a imunomicroscopia eletronica (IEM) e com o ensaio imunoenzimatico (EIE) no exame de 245 fezes de criancas com gastroenterite revelou completa concordancia entre os tres ensaios em 238 (97.14%) amostras. Entre 75 amostras positivas pelo menos em um dos tres ensaios, resultados negativos foram observados em 5 (6.48%) por EGPA, em 6 (6.76%) por EIE e em nenhum por IEM. Coloracao pela prata aumentou consideravelmente a sensibilidade do ensaio por EGPA.Concluimos que embora a IEM ainda seja a prova mais sensivel e rapida para o diagnostico de infeccoes por rotavirus, o ensaio por EGPA tem muitas vantagens em seu favor, sendo as principais as de nao necessitar equipamentos caros, de empregar exclusivamente reagentes quimicamente definidos, de identificar grupos e variantes virais e de detectar amostras que nao possuindo antigenos comuns a maioria dos rotavirus, nao sao revelaveis por ensaios sorologicos

An outbreak of gastroenteritis caused by both rotavirus and Shigella sonnei in a private school in Rio de Janeiro.

In May 1980 an extensive outbreak of gastroenteritis occurred in a private school in the city of Rio de Janeiro. Examination of faeces and paired sera showed that this outbreak was caused by both rotavirus and a virulent strain of Shigella sonnei. In the first 19 stool samples collected seven (37%) had rotavirus only, six (32%) had Sh. sonnei only, while four (21%) had both agents. Examination of the second and third stool collections revealed only the presence of Sh. sonnei. The 18 paired sera showed seroconversion for rotavirus in four cases (22%) and in seven cases (39%) for Sh. sonnei. The overall attack rate of the disease was approximately 75%, the nursery and kindergarten having higher attack rates. Students in all grades became sick at the same time, and the unimodal curve of the onset dates of symptoms indicates a common source outbreak. Evidence suggested a contaminated water supply.