Maria da Conceição Nascimento Costa

Dynamics of dengue virus circulation: a silent epidemic in a complex urban area

Serotypes of dengue DEN‐1 and DEN‐2 have been reported in much of Brazil over the last 15 years, and DEN‐3 serotype was only recently detected. This prospective study was conducted in Salvador, a large city in north‐east Brazil, where two epidemics were previously recorded (DEN‐1 and DEN‐2). We obtained the seroprevalence and 1‐year incidence of dengue infections in the population of 30 sampling areas of Salvador and analysed the relationship between intensity of viral circulation, standard of living and vector density. High seroprevalence (68.7%) and annual incidence (70.6%) of infection for one or both circulating serotypes (DEN‐1 and DEN‐2) were found. High rates of transmission were observed in all studied areas, from the highest to the lowest socio‐economic status. The mean PI (Premise Index) for Aedes aegypti was 7.4% (range 0.27–25.6%). Even in the areas with the lowest PI (≤3%) the observed seroincidence was 54.6%. These findings highlighted the existence of a silent epidemic during a period perceived by the Health Services as of low endemicity, indicating the strength and speed of dengue transmission in the city of Salvador.

Dengue: twenty-five years since reemergence in Brazil

This article revisits the epidemiology of dengue in Brazil, 25 years after its reemergence in the country, discussing the main determinants and implications for its control. The authors emphasize the clinical and epidemiological peculiarities of this viral disease in Brazil, which leads the world in both the number of cases reported and risk of occurrence of the disease. The article presents the changes occurring in the dengue epidemiological pattern in recent years, like the sudden age shift in the incidence of dengue hemorrhagic fever, and discusses possible associated factors. The article focuses specifically on the epidemic in Rio de Janeiro in 2008, this episodes impact on the international community, and the fear that the disease could spread to Europe. The authors conclude that the current situation emphasizes the need for the international scientific community to renew its efforts to generate knowledge allowing improvement and progress in the development of new tools and strategies for dengue prevention.

Dengue and dengue hemorrhagic fever epidemics in Brazil: what research is needed based on trends, surveillance, and control experiences?

Dengue epidemics account annually for several million cases and deaths worldwide. The high endemic level of dengue fever and its hemorrhagic form correlates to extensive domiciliary infestation by Aedes aegypti and multiple viral serotype human infection. This study analyzed serial case reports registered in Brazil since 1981, describing incidence evolutionary patterns and spatial distribution. Epidemic waves followed the introduction of every serotype (DEN 1 to 3), and reduction in susceptible individuals possibly accounted for decreasing case frequency. An incremental expansion of affected areas and increasing occurrence of dengue fever and its hemorrhagic form with high case fatality were noted in recent years. In contrast, efforts based solely on chemical vector control have been insufficient. Moreover, some evidence demonstrates that educational measures do not permanently modify population habits. Thus, as long as a vaccine is not available, further dengue control depends on potential results from basic interdisciplinary research and intervention evaluation studies, integrating environmental changes, community participation and education, epidemiological and virological surveillance, and strategic technological innovations aimed to stop transmission.

Recent shift in age pattern of dengue hemorrhagic fever, Brazil.

To the Editor: Brazil is responsible for >60% of reported cases of dengue fever (DF) in the American region (a designation of the Pan American Health Organization, which includes all of North, Central and South America) (1). The epidemiologic characteristics of dengue diseases in Brazil differ from those described in Southeast Asia. In Brazil, the incidence of DF and dengue hemorrhagic fever (DHF) is highest in adults. By contrast, in Southeast Asia, DHF cases predominate and occur more often in children than in adults (2,3).

Violência e desigualdade social: mortalidade por homicídios e condições de vida em Salvador, Brasil

INTRODUCTION Some studies have been questioning the association between poverty and violence. This studys purpose is to assess the distribution of homicide indicators associated with living conditions in Salvador, Brazil. METHODS A cluster study for the years 1991 to 1994 was carried out including the 75 data centers of the city of Salvador, BA, Brazil. Using death certificates for the study period, yearly mortality rates and mortality ratios were estimated. The 1991 census data of monthly wages and years of education for all family providers were used to define a four-category variable related to living conditions. Mortality rates due to homicide and the relative risk regarding the lowest living condition area were calculated for each social stratum. The 95% confidence intervals were calculated using the Confidence Interval Analysis software. RESULTS The highest mortality rates due to homicide were seen in the poorest areas. The relative risk due to homicide for the lowest and the highest living condition areas was statistically significant at 5% level and ranged from 2.9 to 5.1. CONCLUSIONS The data show a strong association between social inequalities and homicide in this urban area, emphasizing the importance of crime reduction programs.

Allergies and Diabetes as Risk Factors for Dengue Hemorrhagic Fever: Results of a Case Control Study

Background The physiopathology of dengue hemorrhagic fever (DHF), a severe form of Dengue Fever, is poorly understood. We are unable to identify patients likely to progress to DHF for closer monitoring and early intervention during epidemics, so most cases are sent home. This study explored whether patients with selected co-morbidities are at higher risk of developing DHF. Methods A matched case-control study was conducted in a dengue sero-positive population in two Brazilian cities. For each case of DHF, 7 sero-positive controls were selected. Cases and controls were interviewed and information collected on demographic and socio-economic status, reported co-morbidities (diabetes, hypertension, allergy) and use of medication. Conditional logistic regression was used to calculate the strength of the association between the co-morbidities and occurrence of DHF. Results 170 cases of DHF and 1,175 controls were included. Significant associations were found between DHF and white ethnicity (OR = 4.70; 2.17–10.20), high income (OR = 6.84; 4.09–11.43), high education (OR = 4.67; 2.35–9.27), reported diabetes (OR = 2.75; 1.12–6.73) and reported allergy treated with steroids (OR = 2.94; 1.01–8.54). Black individuals who reported being treated for hypertension had 13 times higher risk of DHF then black individuals reporting no hypertension. Conclusions This is the first study to find an association between DHF and diabetes, allergy and hypertension. Given the high case fatality rate of DHF (1–5%), we believe that the evidence produced in this study, when confirmed in other studies, suggests that screening criteria might be used to identify adult patients at a greater risk of developing DHF with a recommendation that they remain under observation and monitoring in hospital.

Infant mortality in Brazil during recent periods of economic crisis

OBJECTIVE To analyze time trends in infant mortality in Brazil during a recent period of economic crisis (1980-1998). METHODS Time-series study based on the Ministry of Healths Mortality Information System, IBGE Foundation and Funda o Nacional de Sa de (National Health Institute database. Serial parameters were described using autoregressive integrated moving average (ARIMA) models, and the association between infant mortality rates and a number of determinants was evaluated using Spearman correlation coefficients. RESULTS Infant mortality showed a declining trend (-59.3%) and a strong correlation with most of the indicators analyzed. However, only correlations between infant mortality rate and total pregnancy and birth rates presented a significant difference between the two decades. CONCLUSIONS Variations in pregnancy rate were the main cause for the persistent decline in infant mortality in the 1980s. In the subsequent period, causes related to living conditions, especially healthcare, may have been more important.

Sentinel areas: a monitoring strategy in public health

Resumo As tecnicas disponiveis para monitoramento da situacao de saude tem-se mostrado insuficientes, razao pela qual se discute a necessidade de aperfeicoa-las com base no desenvolvimento de novas estrategias de coleta de informacoes, de modo a permitir seu uso pelos sistemas locais de saude. Este artigo apresenta as bases metodologicas de uma estrategia de monitoramento de problemas de saude que emprega espacos intra-urbanos delimitados – areas sentinelas – para coleta de informacoes sociais, economicas, comportamentais e biologicas fundamentais para a Saude Publica, por permitirem uma maior aproximacao com a realidade de espacos sociais complexos. Os autores apresentam uma experiencia que esta sendo desenvolvida em Salvador/Bahia, Brasil, para avaliacao de impacto epidemiologico resultante da implantacao de um programa de saneamento ambiental. Discutem-se os criterios de selecao das areas e as potencialidades de uso dessa estrategia para possibilitar o emprego agil dos recursos epidemiologicos pelos servicos de saude de forma agil e a aplicacao oportuna de seus resultados na reorientacao e aprimoramento das praticas de intervencao em saude. Palavras-chave: areas sentinelas; monitoramento; saude publica; vigilância sentinela. Summary Because available techniques for monitoring the health situation have shown to be insufficient, this article discusses methods to improve these techniques based on the development of new strategies of data collection that permit their use by local health systems. The methodological basis of a strategy of health monitoring using well-defined inner-urban spaces, called sentinel areas, is presented. The proposed strategy permits the collection of social, economic, behavioral, and biological information essential for public health practice, including a better approach to the reality of complex social spaces. The authors present an experience developed in the city of Salvador, the capital of Bahia state, Brazil, which has been used to evaluate the epidemiological impact of an environment sanitation program. Criteria for area selection are discussed, as well as the potential use of this strategy by health services, as it allows the use of epidemiological resources and their results for improving health intervention programs in a timely manner.

Spread pattern of the first dengue epidemic in the city of Salvador, Brazil

BackgroundThe explosive epidemics of dengue that have been occurring in various countries have stimulated investigation into new approaches to improve understanding of the problem and to develop new strategies for controlling the disease. The objective of this study was to evaluate the characteristics of diffusion of the first dengue epidemic that occurred in the city of Salvador in 1995.MethodsThe epidemiological charts and records of notified cases of dengue in Salvador in 1995 constituted the source of data. The cases of the disease were georeferenced according to census areas (spatial units) and epidemiological weeks (temporal unit). Kernel density estimation was used to identify the pattern of spatial diffusion using the R-Project computer software program.ResultsOf the 2,006 census areas in the city, 1,400 (70%) registered cases of dengue in 1995 and the spatial distribution of these records revealed that by the end of 1995 practically the entire city had been affected by the virus, with the largest concentration of cases occurring in the western region, composed of census areas with a high population density and predominantly horizontal residences compared to the eastern region of the city, where there is a predominance of vertical residential buildings.ConclusionThe pattern found in this study shows the characteristics of the classic process of spreading by contagion that is common to most infectious diseases. It was possible to identify the epicenter of the epidemic from which centrifugal waves of the disease emanated. Our results suggest that, if a more agile control instrument existed that would be capable of rapidly reducing the vector population within a few days or of raising the group immunity of the population by means of a vaccine, it would theoretically be possible to adopt control actions around the epicenter of the epidemic and consequently reduce the incidence of the disease in the city. This finding emphasizes the need for further research to improve the technology available for the prevention of this disease.

Doença periodontal materna como fator associado ao baixo peso ao nascer

OBJETIVO: Estudos recentes tem apresentado evidencias de que a doenca periodontal em gestantes pode ser um dos determinantes do baixo peso ao nascer. Realizou-se estudo para verificar a existencia de associacao entre doenca periodontal materna e baixo peso ao nascer. METODOS: Estudo do tipo caso-controle com 302 mulheres, sendo 102 maes de nascidos vivos de baixo peso (grupo caso) e 200 maes de nascidos vivos com peso normal (grupo controle). A existencia de associacao entre doenca periodontal e baixo peso ao nascer foi avaliada mediante modelo multivariado de regressao logistica, considerando outros fatores de risco para o baixo peso. RESULTADOS: Ambos os grupos de maes eram comparaveis no que se refere a idade, altura, peso pre-gestacional, tabagismo, alcoolismo, doencas previas, estado civil, situacao socioeconomica, numero de escovacoes e uso de fio dental, numero de refeicoes diarias, e visitas ao dentista. A doenca periodontal foi diagnosticada em 57,8% das maes do grupo caso e 39,0% do grupo controle. A analise de regressao logistica indicou associacao positiva entre doenca periodontal e baixo peso ao nascer (ORbruto=2,15; IC 95%: 1,32-3,48), especialmente entre as maes com escolaridade menor ou igual a quatro anos (ORajustada=3,98; IC 95%: 1,58-10,10). CONCLUSOES: A doenca periodontal e um possivel fator de risco para o baixo peso ao nascer.OBJECTIVE Recent studies have presented evidence that periodontal disease in pregnant women may be a determining factor for low birth weight. The present investigation was carried out to verify whether or not there is an association between maternal periodontal disease and low birth weight. METHODS This was a case-control study on 302 women, of whom 102 were the mothers of live newborns of low weight (case group) and 200 were the mothers of live newborns of normal birth weight (control group). The existence of an association between periodontal disease and low birth weight was evaluated by means of a multivariate logistic regression model that considered other risk factors for low weight. RESULTS The two groups were comparable with regard to age, height, pre-gestational weight, smoking, alcohol use, previous diseases, marital status, socioeconomic status, frequency of tooth-brushing and use of dental floss, number of meals per day and visits to the dentist. Periodontal disease was diagnosed in 57.8% of the mothers in the case group and 39.0% in the control group. Logistic regression analysis indicated a positive association between periodontal disease and low birth weight (unadjusted OR=2.15; 95% CI: 1.32-3.48), especially among the mothers with schooling of less than or equal to four years (ORadjusted=3.98; 95% CI: 1.58-10.10). CONCLUSIONS Periodontal disease is a possible risk factor for low birth weight.