Maria de Fátima Pessoa Militão de Albuquerque

Seroprevalence and risk factors for dengue infection in socio-economically distinct areas of Recife, Brazil.

Brazil currently accounts for the majority of dengue cases reported in the Americas, with co-circulation of DENV 1-3. Striking variation in the epidemiological pattern of infection within cities has been observed. Therefore, investigation of dengue transmission in small areas is important to formulate control strategies. A population-based household survey was performed in three diverse socio-economic and environmental areas of Recife, a large urban center of Brazil, between 2005 and 2006. Dengue serostatus and individual- and household-level risk factors for infection were collected in residents aged between 5 and 64 years. A total of 2833 individuals were examined, and their residences were geo-referenced. Anti-dengue IgG antibodies were measured using commercial ELISA. The dengue seroprevalence and the force of infection were estimated in each area. Individual and household variables associated with seropositivity were assessed by multilevel models for each area. A spatial analysis was conducted to identify risk gradients of dengue seropositivity using Generalized Additive Models (GAM). The dengue seroprevalence was 91.1%, 87.4% 74.3%, respectively, in the deprived, intermediate and high socio-economic areas, inversely related to their socio-economic status. In the deprived area, 59% of children had already been exposed to dengue virus by the age of 5 years and the estimated force of infection was three times higher than that in the privileged area. The risk of infection increased with age in the three areas. Not commuting away from the area was a risk factor for seropositivity in the deprived area (OR=2.26; 95% CI: 1.18-4.30). Number of persons per room was a risk factor for seropositivity in the intermediate (OR=3.00; 95% CI: 3.21-7.37) and privileged areas (OR=1.81; 95% CI: 1.07-3.04). Living in a house, as opposed to an apartment, was a risk factor for seropositivity in the privileged area (OR=3.62; 95% CI: 2.43-5.41). The main difference between the privileged and other areas could be attributed to the much larger proportion of apartment dwellers. Intensive vector control, surveillance and community education should be considered in deprived urban areas where a high proportion of children are infected by an early age.

Evaluation of PCR for Diagnosis of American Cutaneous Leishmaniasis in an Area of Endemicity in Northeastern Brazil

ABSTRACT PCR-based approaches targeting kinetoplast DNA were evaluated for the diagnosis of American cutaneous leishmaniasis (ACL) in regions of endemicity in northeastern Brazil. A total of 119 cutaneous biopsy specimens from patients with ACL and nonleishmaniasis cutaneous lesions were studied. Two PCR-based systems were used; one was specific for the subgenus Viannia, and the other was specific for the genus Leishmania. The PCR specific for the subgenus Viannia had a sensitivity of 95.4%, whereas the genus-specific PCR detected the target DNA in 88.2% of the samples tested. The specificities of the assays, determined with samples from a group with nonleishmaniasis cutaneous lesions, was 100%. The results of the conventional tests indicate that the sensitivities of the PCR-based methods were significantly higher than those of smear examination, histological staining, and isolation by culture (P < 0.05). Antibodies specific for Leishmania braziliensis were detected by indirect immunofluorescence in 82.9% of the patients tested. Parasites were isolated from 40 of 86 patients (46.5%). Sixty-seven percent of dermal scrapings and 66.2% of stained tissue sections were positive by microscopy. Amplified products from the subgenus-specific PCR hybridized with the Leishmania panamensis minicircle, confirming infection consistent with L. braziliensis. The evidence available at present incriminates L. braziliensis as the only causative agent of ACL in the state of Pernambuco in Brazil.

Smoking increases the risk of relapse after successful tuberculosis treatment

Background Recent tobacco smoking has been identified as a risk factor for developing tuberculosis, and two studies which have investigated its association with relapse of tuberculosis after completion of treatment had conflicting results (and did not control for confounding). The objective of this study was to investigate risk factors for tuberculosis relapse, with emphasis on smoking. Methods A cohort of newly diagnosed TB cases was followed up from their discharge after completion of treatment (in 2001–2003) until October 2006 and relapses of tuberculosis ascertained during that period. A case of relapse was defined as a patient who started a second treatment during the follow up. Results Smoking (OR 2.53, 95% CI 1.23–5.21) and living in an area where the family health program was not implemented (OR 3.61, 95% CI 1.46–8.93) were found to be independently associated with relapse of tuberculosis. Conclusions Our results establish that smoking is associated with relapse of tuberculosis even after adjustment for the socioeconomic variables. Smoking cessation support should be incorporated in the strategies to improve effectiveness of Tuberculosis Control Programs.

Factors associated with treatment failure, dropout, and death in a cohort of tuberculosis patients in Recife, Pernambuco State, Brazil

A cohort of cases initiating tuberculosis treatment from May 2001 to July 2003 was followed in Recife, Pernambuco State, Brazil, to investigate biological, clinical, social, lifestyle, and healthcare access factors associated with three negative tuberculosis treatment outcomes (treatment failure, dropout, and death) separately and as a group. Treatment failure was associated with treatment delay, illiteracy, and alcohol consumption. Factors associated with dropout were age, prior TB treatment, and illiteracy. Death was associated with age, treatment delay, HIV co-infection, and head of familys income. Main factors associated with negative treatment outcomes as a whole were age, HIV co-infection, illiteracy, alcoholism, and prior TB treatment. We suggest the following strategies to increase cure rates: further training of the Family Health Program personnel in TB control, awareness-raising on the need to tailor their activities to special care for cases (e.g., literacy training); targeting use of directly observed therapy for higher risk groups; establishment of a flexible referral scheme to handle technical and psychosocial problems, including alcoholism; and increased collaboration with the HIV/AIDS program.

Characteristics of pulmonary tuberculosis in HIV seropositive and seronegative patients in a Northeastern region of Brazil

The aim of this study was to analyse the clinical, epidemiological and bacteriological features present in 60 pulmonary tuberculosis patients who were also infected with human immunodeficiency virus (HIV) and to compare these with 120 TB patients who were not infected with HIV. The patients with pulmonary tuberculosis and HIV coinfection were mostly male (p = 0.001), showed a higher frequency of weight loss >10 kilos (p <0.001), had a higher rate of non-reaction result to the tuberculin skin test (p <0.001), a higher frequency of negative sputum smear examination for acid-fast bacilli (p = 0.001) and negative sputum culture for Mycobacterium tuberculosis (p = 0.001). Treatment failure was more common in those who were HIV positive (p <0.000). No higher frequency of resistance to antituberculosis drugs was found to be associated with TB/HIV coinfection (p = 0.407). Association between extrapulmonary and pulmonary tuberculosis was more frequent in those seropositive to HIV than those without HIV virus, 30% and 1.6% respectively. These findings showed a predominance of atypical clinical laboratory features in co-infected patients, and suggest that health care personnel should consider the possibility this diagnosis.

Tuberculose no Brasil: construção de um sistema de vigilância de base territorial

OBJECTIVE: To analyze the occurrence of tuberculosis and to identify variables that define situations of collective risk that determine the spatial distribution of the disease, as backing for implementing a territory-based surveillance system for tuberculosis control. METHODS: This was an ecological study performed in Olinda, a municipality in the metropolitan region of Recife, State of Pernambuco, between 1996 and 2000. The median number of notified tuberculosis cases in each census tract served as the cutoff point for characterizing areas of high and low transmission. A logistic regression model using this response variable allowed odds ratios for some socioeconomic variables from the 2000 demographic census and other covariates related to the transmission of the disease to be estimated. RESULTS: Tuberculosis in Olinda presented high incidence rates during the study period (average of 111 cases per 100,000 inhabitants). Significant associations with the occurrence of tuberculosis were found for the variables of average number of inhabitants per household (OR=2.2; 95% CI: 1.3; 3.6); existence of families with more than one case during the study period (OR=5.1; 95% CI: 2.3; 11.3); and presence of cases of retreatment (OR=6.8; 95% CI: 2.7; 17.1). The census tract where the latter two events occurred accounted for 45% of the total number of cases during the study period, while representing only 28% of the population of Olinda. CONCLUSIONS: The two explanatory covariates that were strongly associated with higher incidence rates of the disease are events that need to be carefully monitored at a local level by the tuberculosis surveillance system. Simply by mapping out retreatment cases and households with more than one case, attention could be focused on small areas with high priority for intensive intervention, thus facing up to the tuberculosis problem.

Vigilância da hanseníase em Olinda, Brasil, utilizando técnicas de análise espacial

In the State of Pernambuco, Brazil, leprosy has been mainly an urban disease, with an uneven geographical distribution related at least partially to the way urban space has been occupied and transformed. Spatial analysis may thus become an important tool to establish an epidemiological surveillance system for leprosy. Homogeneous micro-areas were defined in the city of Olinda through the integration of two databases, the Population Census and SINAN, and through the use of digital maps and geoprocessing techniques. Census tracts were classified according to a social deprivation index (SDI), and micro-area homogeneity was based on similar values for this indicator. Cluster analysis (K-means) was used to define cut-offs between strata. The same procedure was repeated using the income variable only. When the association was tested between the mean SDI value and the mean leprosy detection rate for the period 1991-1996, the value obtained for r2 was 66.1% in the multiplicative model, increasing to 84.3% when the income variable was used. To define different intervention strategies, census tracts were regrouped in three levels of risk: high, moderate, and low. The methodology enabled the identification (within each health district) of groups and/or areas with different risk of leprosy, hence allowing for the definition of control measures.

Aplicação de modelo bayesiano empírico na análise espacial da ocorrência de hanseníase

OBJETIVO: Analisar a distribuicao espacial da hanseniase, identificar areas de possivel sub-registro de casos ou de provavel alta transmissao (risco) e verificar a associacao dessa distribuicao a existencia de casos de formas multibacilares. METODOS: O estudo foi realizado em Recife, PE, de acordo com 94 bairros analisados. A fonte de coleta de dados foi o Sistema de Informacoes sobre Agravos de Notificacao do Ministerio da Saude. Foi adotada uma abordagem ecologica com utilizacao do metodo bayesiano empirico para suavizacao local de taxas, a partir de informacoes de bairros vizinhos por adjacencia. RESULTADOS: A ocorrencia media anual foi de 17,3% de casos novos em menores de 15 anos (28,3% de formas multibacilares), indicando um processo de intensa transmissao da doenca. A analise da distribuicao espacial de hanseniase apontou tres areas onde se concentram bairros com taxas de deteccao elevadas e que possuem baixa condicao de vida. CONCLUSOES: O emprego do modelo bayesiano, baseado em informacoes de unidades espaciais vizinhas, permitiu estimar novamente indicadores epidemiologicos. Foi possivel identificar areas prioritarias para o programa de controle de hanseniase no municipio, tanto pelo elevado numero de ocorrencias correlacionado a presenca de formas multibacilares de doenca em menores de 15 anos quanto pela existencia de subnotificacao.

Is it better to be rich in a poor area or poor in a rich area? A multilevel analysis of a case–control study of social determinants of tuberculosis

BACKGROUND Tuberculosis is known to have socio-economic determinants at individual and at area levels, but it is not known whether they are independent, whether they interact and their relative contributions to the burden of tuberculosis. METHODS A case-control study was conducted in Recife, Brazil, to investigate individual and area social determinants of tuberculosis, to explore the relationship between determinants at the two levels and to calculate their relative contribution to the burden of tuberculosis. It included 1452 cases of tuberculosis diagnosed by the tuberculosis services and 5808 controls selected at random from questionnaires completed for the demographic census. Exhaustive information on social factors was collected from cases, using the questionnaire used in the census. Socio-economic information for areas was downloaded from the census. Multilevel logistic regression investigated individual and area effects. RESULTS There was a marked and independent influence of social variables on the risk of tuberculosis, both at individual and area levels. At individual level, being aged >or=20, being male, being illiterate, not working in the previous 7 days and possessing few goods, all increased the risk of tuberculosis. At area level, living in an area with many illiterate people and where few households own a computer also increased this risk; individual and area levels did not appear to interact. Twice as many cases were attributable to social variables at individual level than at area level. CONCLUSIONS Although individual characteristics are the main contributor to the risk of tuberculosis, contextual characteristics make a substantial independent contribution.

Vigilância de doenças endêmicas em áreas urbanas: a interface entre mapas de setores censitários e indicadores de morbidade

In this article we discuss the methodological issues associated with the creation of a surveillance system for endemic diseases in urban areas based on analysis of populations at risk and on spatially referenced epidemiological indicators. We comment on the systems basic requirements, selection criteria for socioeconomic variables, and methodological steps to combine these variables so as to construct a census-based deprivation index. We also present the ways we solved some operational problems related to generation of digitized census tracts maps and linkage of morbidity data from different sources. This approach, spatial organization into account in surveillance of endemic diseases, exemplified here by tuberculosis and leprosy, allows for the interaction of several official data sets from census and health services in order to geographically discriminate inner-city risk strata. Criteria for constructing these risk strata were considered a useful tool for health planning and management activities for the control of endemic diseases in cities.