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Biomedical subjects

F I Bastos

Publications and source records attributed to F I Bastos.

At least 19 recordsLinked to original sources
PubMed2006

A qualitative assessment of long distance truck drivers' vulnerability to HIV/AIDS in Itajaí, southern Brazil.

Itajaí is the largest port in southern Brazil and has one of the nation's highest AIDS incidence rates. Since over 400 truck drivers enter the city daily, they may play a key role in the HIV/AIDS epidemic due to transactions with commercial sex workers (CSWs) and/or substance use. We conducted a rapid assessment to establish the context of HIV vulnerability among truckers and CSWs in Itajaí. Forty three in-depth interviews and eight focus groups were conducted with truckers and CSWs. Two truck-driving routes involving brothels, meeting places and drug-use locations were mapped and field observations were collected. Tapes and field notes were transcribed and analyzed for emerging themes. Truck drivers typically had unprotected sex with several partners, including CSWs and truckstop employees. Both truckers and CSWs had low perceived HIV risk in spite of being engaged in high-risk sex behaviors. Use of alcohol and amphetamine-like drugs was frequent among truckers and appeared to influence unsafe sex practices. Knowledge about amphetamine-related risks was low, as was access to health services and HIV/AIDS behavioral interventions. Interventions, targeting truckers, CSWs and truckstop employees, are needed that traverse cities, states and borders and take into account seasonality, spatial context and workplace conditions.

Alcohol Drinking↗
PubMed2005

HIV-1 binding and neutralizing antibodies of injecting drug users.

Previous studies have demonstrated a stronger seroreactivity against some synthetic peptides responsible for inducing neutralizing antibodies in injecting drug users (IDU) compared to that of individuals sexually infected with HIV-1 (S), but the effectiveness in terms of the neutralizing ability of these antibodies has not been evaluated. Our objective was to study the humoral immune response of IDU by determining the specificity of their antibodies and the presence of neutralizing antibodies. The neutralization capacity against the HIV-1 isolate MN (genotype B), the primary HIV-1 isolate 95BRRJ021 (genotype F), and the seroreactivity with peptides known to induce neutralizing antibodies, from the V2 and V3 loops of different HIV-1 subtypes, were analyzed. Seroreactivity indicates that IDU plasma are more likely to recognize a broader range of peptides than S plasma, with significantly higher titers, especially of V3 peptides. Similar neutralization frequencies of the MN isolate were observed in plasma of the IDU (16/47) and S (20/60) groups in the 1:10 dilution. The neutralization of the 95BRRJ021 isolate was more frequently observed for plasma from the S group (15/23) than from the IDU group (15/47, P = 0.0108). No correlation between neutralization and seroreactivity with the peptides tested was observed. These results suggest that an important factor responsible for the extensive and broad humoral immune response observed in IDU is their infection route. There was very little difference in neutralizing antibody response between the IDU and S groups despite their differences in seroreactivity and health status.

Cross Reactions↗
PubMed2005

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals.

Anti-human immunodeficiency virus type 1 (HIV-1) "binding antibodies" (antibodies capable of binding to synthetic peptides or proteins) occur throughout HIV-1 infection, are high-titered and highly cross-reactive, as confirmed in this study by analyzing plasma from B and F genotype HIV-1 infected individuals. Plasma from individuals infected with clade F HIV-1 displayed the most frequent cross-reactivity, in high titers, while Bbr plasma showed much higher specificity. Similarly, neutralization of a reference HIV-1 isolate (HIV-1 MN) was more frequently observed by plasma from F than B genotype infected individuals. No significant difference was seen in neutralization susceptibility of primary B, Bbr or F clade HIV-1 by plasma from individuals infected with the classical B (GPGR) or F HIV-1, but Bbr (GWGR) plasma were less likely to neutralize the F genotype primary HIV-1 isolates. The data indicate that both B and F genotype derived vaccines would be equally effective against B and F HIV-1 infection, with a slightly more probable effectiveness for F than B genotype. Although the Bbr variant appears to induce a much more specific humoral immune response, the susceptibility in neutralizing the Brazilian HIV-1 B genotype Bbr variant is similar to that observed with the classical B genotype HIV-1.

AIDS Vaccines↗
PubMed2005

The impact of the transmission dynamics of the HIV/AIDS epidemic on sexual behaviour: a new hypothesis to explain recent increases in risk taking-behaviour among men who have sex with men.

Increases in sexually transmitted infections and related high-risk behaviours have been reported among men who have sex with men (MSM) in industrialised countries when effective antiretroviral therapy against HIV infection has become widely available, in the mid-nineties. The reasons for these increases are not fully understood and often conflicting. Prevention fatigue, relapses to unsafe sex, as well as optimism toward the risk of developing AIDS among people living with HIV are not unique to the era of antiretroviral therapy (ART). This has led researchers to highlight the need to investigate other potential reasons that could explain the increase in high-risk taking following the ART introduction. We put forward the hypothesis that the change in the transmission dynamics of the HIV/AIDS epidemic before and after the introduction of ART has contributed to this change in high-risk behaviour. It is suggested that a decline in sexual risk activities has occurred at the population-level following the initial spread of the HIV/AIDS epidemic because AIDS mortality and severe morbidity disproportionately depleted the pool of high-risk taking individuals. As a result, non-volitional changes may have occurred at the individual-level over time because the depletion of this pool of high-risk individuals made it more difficult for the remaining high-risk taking individuals to find partners to engage in risky sex with. Following its introduction, ART has facilitated the differential replenishment of the pool of individuals willing to engage in high-risk taking behaviours because ART reduces AIDS mortality, and morbidity. Consequently, high-risk taking individuals who had previously reduced their level of risky sex non-volitionally (i.e., as a result of the reduced availability of high-risk partners) were able to resume their initial high-risk practices as the pool of high-risk taking individuals replenished over time. Thus, a fraction of the recently reported increase in high-risk sexual activities may be secondary to the fact that those MSM who were unable to engage in their desired high-risky sexual activities (because of reduced availability) are now able to revert to them as the availability of men willing to engage in risky sexual behaviours increases partly due to ART. Therefore, we suggest that a fraction of the changes in individual behaviour are non-volitional and can be explained by a change in "sexual partner availability" due to the transmission dynamics of HIV/AIDS before and after ART. The hypothesis is formulated and explained using simple social network diagrams and the Theory of Planned Behaviour. We also discuss the implication of this hypothesis for HIV prevention.

Acquired Immunodeficiency Syndrome↗
PubMed2004

[The hidden face of AIDS in Brazil].

The authors report on the evolution of the AIDS epidemic in Brazil from the point of view of the construction of social representations about "risk groups" involved in the spread of the disease. They emphasize the need to demystify the immediate correlation between AIDS and homosexual transmission. They highlight the role of intravenous drug users and of heterosexual transmission in new AIDS cases in Brazil - groups and behaviours that are not included in the priorities of local health authorities.

English Abstract↗
PubMed2003

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.

AIDS Vaccines↗
PubMed2001

Retrovirus infections in a sample of injecting drug users in Rio de Janeiro City, Brazil: prevalence of HIV-1 subtypes, and co-infection with HTLV-I/II.

BACKGROUND: Retrovirus infections among injecting drug users (IDUs), a core at-risk population for both HIV-1 and HTLV-I/II infections in Brazil, were assessed within an ongoing cooperative research. OBJECTIVE: The study assessed the seroprevalences of HIV-1 and HTLV-I/II infections, as well as the prevalence of HIV-1 subtypes in a sample of IDUs from Rio de Janeiro, Brazil. An attempt to evaluate HIV incidence was carried out using a dual 'sensitive/less sensitive' testing strategy. STUDY DESIGN: Cross-sectional evaluation of 175 IDUs. Serostatus for HIV-1 and HTLV-I/II were established by enzyme-linked immunosorbent assays, and confirmed by western blot. The dual testing strategy aimed to estimate HIV-1 incidence rates. Differentiation between HTLV-I and -II was performed by western blot. DNA samples were polymerase chain reaction amplified by a nested protocol, and HIV-1 subtyping was determined by heteroduplex mobility assay. RESULTS: Forty-six and 29 samples were found to be, respectively, positive for HIV-1 and HTLV-I/II, 15 of them co-infected by both viruses. Among HTLV-I/II-infected patients, 75.9% were infected by HTLV-I. Thirty-one HIV samples were identified as B subtype, with seven of them showing the typical "Brazilian B" pattern in the gp120 V3 loop, and ten were identified as F subtype. The use of less sensitive assays for HIV infection wrongly identified a deeply immunocompromised patient as an incident case. CONCLUSION: Moderately high seroprevalences were found for both HIV-1 and HTLV-I/II infections, HIV-1/HTLV-I co-infections being of special concern. A non-statistically significant higher prevalence of F subtype was observed, when compared with the distribution of F/B subtypes among Brazilian patients from other exposure categories. No recent HIV-1 infections were detected, but a limitation of the "sensitive/less-sensitive" testing strategy was made evident.

Adult↗
PubMed2000

Differential trends in mortality from AIDS in men and women in Brazil (1984-1995).

OBJECTIVE: To analyse trends in AIDS mortality in men and women in Brazil, for the period 1984-1995. DESIGN AND METHODS: National statistics on yearly numbers of reported deaths by cause, in conjunction with census population counts and inter-censory estimates, were used to calculate age- and sex-specific AIDS mortality rates for Brazil as a whole and for São Paulo and Rio de Janeiro, the two largest cities in Brazil, and those most affected by the AIDS epidemic to date. RESULTS: Numbers of reported deaths from AIDS have increased yearly in Brazil since 1984, to approximately 15,000 in 1995. The data suggest that after a very dramatic rise in mortality rates, the epidemic may have started to slow even before the introduction of freely available highly-active anti-retroviral therapy, although unequally in terms of both geographical and sex distributions. Women also tended to die at relatively younger ages than men in all areas studied, and by 1995 the impact of AIDS on overall mortality was practically the same for men and women aged 25-34 years (21% in São Paulo). CONCLUSIONS: Trends in mortality from AIDS in Brazil reflect both the geographical expansion of the epidemic outwards from its original epicentres, and the fact that women are becoming increasingly affected by the AIDS epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Evaluating effectiveness of syringe exchange programmes: current issues and future prospects.

Although a large body of international literature has found syringe exchange programmes (SEPs) to be associated with reduced incidence of blood borne pathogens among injection drug users, recent studies have fuelled controversy surrounding SEP effectiveness. Existing studies are observational in nature and have seldom considered ecologic aspects affecting SEP functioning and evaluation. The authors apply concepts from infectious disease epidemiology to discuss the direct and indirect effects of SEP upon the spread of blood borne pathogens in drug users, their social networks and the broader community. Further, the authors discuss social policies, particularly drug control policies, which have directly and/or indirectly limited SEP functioning at local and national levels. A critical review of the literature suggests that biases common to observational studies can account for higher HIV incidence among SEP attenders relative to non-attenders. Strong selection factors often lead high-risk drug users to be over-represented among SEP attenders. Failure to account for these factors and the indirect effects of SEPs can bias interpretations of programme effectiveness. Future SEP evaluations should consider behavioural data, the local ethnographic context, the prevalence of infectious disease in the groups under study and the structural components of SEP that are most and least effective at reducing incidence of blood borne pathogens. Hierarchical models that take into account the ecological dimensions of SEP are recommended as an approach for future studies. Beyond methodologic concerns, the authors discuss social, legal and programmatic obstacles that must be overcome in order to maximise SEP effectiveness.

Blood-Borne Pathogens↗
PubMed2000

Health conditions and residential concentration of poverty: a study in Rio de Janeiro, Brazil.

STUDY OBJECTIVES: To establish the geographical relation of health conditions to socioeconomic status in the city of Rio de Janeiro, Brazil. DESIGN: All reported deaths in the municipality of Rio de Janeiro, from 1987 to 1995, obtained from the Mortality Information System, were considered in the study. The 24 "administrative regions" that compose the city were used as the geographical units. A geographical information system (GIS) was used to link mortality data and population census data, and allowed the authors to establish the geographical pattern of the health indicators considered in this study: "infant mortality rate"; "standardised mortality rate"; "life expectancy" and "homicide rate". Information on location of low income communities (slums) was also provided by the GIS. A varimax rotation principal component analysis combined information on socioeconomic conditions and provided a two dimension basis to assess contextual variation. MAIN RESULTS: The 24 administrative regions were aggregated into three different clusters, identified as relevant to reflect the socioeconomic variation. Almost all health indicator thematic maps showed the same socioeconomic stratification pattern. The worst health situation was found in the cluster composed of the harbour area and northern vicinity, precisely in the sector where the highest concentration of slum residents are present. This sector of the city exhibited an extremely high homicide rate and a seven year lower life expectancy than the remainder of the city. The sector that concentrates affluence, composed of the geographical units located along the coast, showed the best health situation. Intermediate health conditions were found in the west area, which also has poor living standards but low concentration of slums. CONCLUSIONS: The findings suggest that social and organisation characteristics of low income communities may have a relevant role in understanding health variations. Local health and other social programmes specifically targeting these communities are recommended.

Adolescent↗
PubMed2000

Sexual behaviour and infection rates for HIV, blood-borne and sexually transmitted infections among patients attending drug treatment centres in Rio de Janeiro, Brazil.

A survey was carried out in 2 drug use treatment centres (TCs) in Rio de Janeiro, Brazil, to assess risk behaviours, HIV infection and other sexually transmitted infections/blood-borne infections (STIs/BBIs). Two hundred and twenty-five drug users (195 males and 30 females) were interviewed and clinically examined, and their blood and urine were tested for STIs/BBIs. Prevalences (%) for these infections were as follows--HIV: 0.9, hepatitis B virus (HBV): 14.7, hepatitis C virus (HCV): 5.8, syphilis: 5.3, gonorrhoea/chlamydia (CT/NG): 4.7. In bivariate analyses CT/NG infection was associated with younger age (P=0.003); current genitourinary symptoms (odds ratio [OR]=6.2) and a mainly illegal source of income (OR=9.1). Hepatitis C infection was associated with a history of ever having injected any drug (OR=19.6), and with each one of the injected drugs. After multiple logistic regression, lower educational level (adjusted odds ratio [AOR]=3.70) and 'ever having injected drugs' (AOR=3.69) remained as independent risk factors for hepatitis B infection. In conclusion, TCs must implement programmes directed towards the prevention of STIs/BBIs.

Adolescent↗
PubMed2000

Human immunodeficiency virus/acquired immunodeficiency syndrome and tropical diseases: a Brazilian perspective.

The paper summarizes recent findings on the epidemiology and pathogenesis of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/Aids), highlighting the role of co-infections with major tropical diseases. Such co-infections have been studied in the Brazilian context since the beginning of the Aids epidemic and are expected to be more frequent and relevant as the Aids epidemic in Brazil proceeds towards smaller municipalities and the countryside, where tropical diseases are endemic. Unlike opportunistic diseases that affect basically the immunocompromised host, most tropical diseases, as well as tuberculosis, are pathogenic on their own, and can affect subjects with mild or no immunosuppression. In the era of highly active anti-retroviral therapies (HAART), opportunistic diseases seem to be on decrease in Brazil, where such medicines are fully available. Benefiting from HAART in terms of restoration of the immune function, putative milder clinical courses are expected in the future for most co-infections, including tropical diseases. On the other hand, from an ecological perspective, the progressive geographic diffusion of Aids makes tropical diseases and tuberculosis a renewed challenge for Brazilian researchers and practitioners dealing with HIV/Aids in the coming years.

Acquired Immunodeficiency Syndrome↗
PubMed2000

[The spread of the AIDS epidemic in Brazil from 1987 to 1996: a spatial analysis].

Mean AIDS incidence rates were calculated for three time periods, 1987-89, 1990-92, and 1993-96, using reported adult AIDS cases by county. The analysis included the following variables: "population of counties for resident AIDS cases"; "proportion of population residing in urban areas", and "concentration of poverty", stratifying by gender and exposure categories. The Southeast region has experienced the lowest increase, contrasting with the steep rise observed in the North and South between the second and third study periods. Comparing variations in incidence rates from 1990-92 and 1993-96 by region or population, the greatest increase was among women. In the larger cities, AIDS cases among "homo/bisexual men" predominate, although the proportion of cases among men who have sex with men has decreased as heterosexual cases have undergone a continuous increase. IDUs have been the core stratum in medium-sized counties. For the smallest counties, heterosexual transmission has been the basic element in local dynamics. Even though AIDS is still an urban phenomenon in Brazil, the epidemic is spreading to rural counties. Until recently it has mainly affecting relatively more affluent areas, but there is now an evident spread of the epidemic to poorer areas.

Acquired Immunodeficiency Syndrome↗
PubMed2000

[AIDS and pauperization: principal concepts and empirical evidence].

This paper discusses methodologies for analyzing relations between social inequalities, marginalization, prejudice, and vulnerability to HIV/AIDS, highlighting current difficulties and alternative research strategies. It also reviews the international and Brazilian literature, emphasizing: economic and macropolitical dimensions in the spread of HIV/AIDS; the role of drug policies and consumption; gender inequalities and prejudice; racial/ethnic inequalities and prejudice; and interaction with other STIs and their relationship to poverty; HIV/AIDS and health care standards, especially access to antiretroviral therapy; and human rights violations. Despite current methodological dilemmas in analyzing relations between psychosocial, cultural, and sociopolitical variables and vulnerability to HIV/AIDS and the limited Brazil literature, such themes merit further investigation, addressing Brazilian social and cultural specificities and profiting from recently developed research strategies.

Acquired Immunodeficiency Syndrome↗
PubMed2000

[AIDS and level of education in Brazil: temporal evolution from 1986 to 1996].

This article analyzes the temporal distribution of reported AIDS cases by level of education used as a proxy variable for individual socioeconomic status. All AIDS cases aged 20-69 years and reported through May 29, 1999, with date of diagnosis between 1986-1996, were included in the study. Incidence rates were calculated for men and women according to level of education ("level 1" up to 8 years of schooling and "level 2" with over 8 years of schooling), by five geographic regions, and by year of diagnosis. Incidence rates for men with less schooling were close to or higher than those for men with more schooling (particularly in the Southeast region). For women, a time series showed that incidence rates increased at a higher rate among women with less schooling in all regions of the country; in the Southeast, the incidence rate for women with less schooling was already greater than for women with more schooling by 1989. According to the present analysis, the AIDS epidemic in Brazil began among people from the more highly educated social strata and progressed steadily through to the less educated social strata, especially among women.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Anti-HIV-1 seroreactivity and HIV transmission route[R1]. The HEC/FIOCRUZ AIDS Clinical Research Group.

BACKGROUND: Antibody binding assays carried out by our group have consistently indicated a higher reactivity of sera from male HIV-1 infected individuals. This study was carried out in order to analyze the importance of gender, route of transmission, disease progression and HIV-1 genotype in seroreactivity assays. STUDY DESIGN: Specificity of antibody binding was studied in plasma of 247 HIV-1 seropositive individuals belonging to patient groups of pregnant women, injecting drug users (IDUs) and recent seroconvertors, resident in Rio de Janeiro, RJ. Recognition of synthetic peptides corresponding to antigenically important epitopes in the envelope of HIV-1 (gp41 immunodominant epitope, V3 loop, V2 loop and gp41 735-752 epitope) was determined. RESULTS: The immunodominant gp41 peptide (amino acids 594-613, HIV-1 MN sequence) was recognized by 85% of all plasma tested. Reactivity with the gp41 735-752 peptide and gp120 V2 loop peptides was low but quite variable, being generally more often specific to a Brazilian V2 peptide used than to the HIV-1 MN derived V2 peptide. The overall recognition of the different V3 peptides tested varied from 41 to 76%. Patients with more advanced disease showed a more frequent reactivity with the peptides studied than did asymptomatic patients. Statistically significant differences in peptide recognition were observed by multiple logistic analyses comparing plasma derived from individuals infected by blood or sexual HIV transmission, adjusting for disease progression and gender. Plasma from individuals infected by sexual transmission showed lower peptide recognition than did plasma from individuals infected through HIV positive blood. Association attempts between seroreactivity and genotype indicated that plasma derived from patients infected with HIV-1 of the F subtype showed highest recognition of heterologous V3 peptides, as well as a slightly more frequent recognition of the non-V3 peptides tested. Recognition of homologous peptides was generally higher than recognition of heterologous peptides. Differences were most pronounced between the prototypical HIV-1 B subtype and the Brazilian B" variant of this subtype but almost non-existent between the HIV-1 B and F subtypes. CONCLUSIONS: Individual gender was shown to be a confounder when investigating the relationships of peptide reaction to HIV-1 route of transmission through multivariate statistical methods: patients infected by blood transmission (IDU) present higher frequency of peptide recognition than individuals infected by sexual HIV-1 transmission. Plasma from individuals infected with the B" variant (GWG) of B subtype HIV-1 showed lower heterologous peptide recognition than that from HIV-1 B (GPG) or F infected individuals.

Amino Acid Sequence↗
PubMed1999

Co-infection with malaria and HIV in injecting drug users in Brazil: a new challenge to public health?

AIMS: To describe AIDS and malaria geography in Brazil, highlighting the role of injecting drug users (IDUs) in malaria outbreaks occurring in malaria-free regions, and the potential clinical and public health implications of malaria/HIV co-infection. DESIGN: Review of the available literature and original analyses using geoprocessing and spatial analysis techniques. FINDINGS: Both HIV/AIDS and malaria distribution are currently undergoing profound changes in Brazil, with mutual expansion to intersecting geographical regions and social networks. Very recent reports describe the first clinical case of AIDS in a remote Amazonian ethnic group, as well as malaria cases in Rio de Janeiro state (hitherto a malaria-free area for 20 years); in addition, two outbreaks of both infections occurred at the beginning of the 1990s in the most industrialized Brazilian state (São Paulo), due to the sharing of needles and syringes by drug users. Spatial data point to: (a) the expansion of HIV/AIDS towards malarigenic areas located in the centre-west and north of Brazil, along the main cocaine trafficking routes, with IDU networks apparently playing a core role; and (b) the possibility of new outbreaks of secondary malaria in urban settings where HIV/AIDS is still expanding, through the sharing of needles and syringes. CONCLUSIONS: New outbreaks of cases of HIV and malaria are likely to occur among Brazilian IDUs, and might conceivably contribute to the development of treatment-resistant strains of malaria in this population. Health professionals should be alert to this possibility, which could also eventually occur in IDU networks in developed countries.

AIDS-Related Opportunistic Infections↗