Epidemiological indicators of Chagas disease in the metropolitan region of Salvador, Bahia, Brazil.

BACKGROUND: Chagas disease (CD) is caused by Trypanosoma cruzi and transmitted by triatomines. Historical information from the 20th century demonstrates T. cruzi records in the metropolitan region of Salvador (MRS), the third largest urban agglomeration in the Brazilian Northeast and the eighth largest in Brazil, an area with intense migratory activity from CD-endemic regions. Therefore, this study aimed to evaluate CD indicators (prevalence and mortality) in the MRS. METHODS: A mixed ecological and descriptive study was conducted using secondary data. We analyzed data from 2008 to 2015: deaths due to CD, self-reported cases of CD, and blood donors that were non-negative for T. cruzi infection. RESULTS: São Francisco do Conde was one of the municipalities with the highest mortality rates due to CD. The seroprevalence rates varied by year and municipality; those with the highest values were 2008: Vera Cruz, 2009: Mata de São João, 2010: Dias D'Ávila, 2011 and 2015: São Francisco do Conde, 2012: São Sebastião do Passé, and 2013 and 2014: Pojuca. Spatial correlations between the municipalities were not detected. CONCLUSIONS: We conclude that CD is present in the MRS. The indicators analyzed in the MRS are below-state-level data. Given the importance of indicator analysis for the surveillance and control of CD at the state and national levels, it is important to strengthen the surveillance program at the municipal level, including the regions classified as low risk for T. cruzi vector transmission.

Epidemiological indicators of Chagas disease in the metropolitan region of Salvador, Bahia, Brazil

ABSTRACT Background: Chagas disease (CD) is caused by Trypanosoma cruzi and transmitted by triatomines. Historical information from the 20th century demonstrates T. cruzi records in the metropolitan region of Salvador (MRS), the third largest urban agglomeration in the Brazilian Northeast and the eighth largest in Brazil, an area with intense migratory activity from CD-endemic regions. Therefore, this study aimed to evaluate CD indicators (prevalence and mortality) in the MRS. Methods: A mixed ecological and descriptive study was conducted using secondary data. We analyzed data from 2008 to 2015: deaths due to CD, self-reported cases of CD, and blood donors that were non-negative for T. cruzi infection. Results: São Francisco do Conde was one of the municipalities with the highest mortality rates due to CD. The seroprevalence rates varied by year and municipality; those with the highest values were 2008: Vera Cruz, 2009: Mata de São João, 2010: Dias D'Ávila, 2011 and 2015: São Francisco do Conde, 2012: São Sebastião do Passé, and 2013 and 2014: Pojuca. Spatial correlations between the municipalities were not detected. Conclusions: We conclude that CD is present in the MRS. The indicators analyzed in the MRS are below-state-level data. Given the importance of indicator analysis for the surveillance and control of CD at the state and national levels, it is important to strengthen the surveillance program at the municipal level, including the regions classified as low risk for T. cruzi vector transmission.

Spatial distribution of congenital syphilis in the state of Bahia, Brazil from 2009 to 2018.

Objective: To describe the temporal trend and spatial distribution of congenital syphilis (CS) cases in the state of Bahia, Brazil between 2009 and 2018. Method: Mixed ecological study conducted through the analysis of data obtained from the Notifiable Diseases Information System and the Live Birth Information System. Global Moran Index I was performed in order to analyze spatial autocorrelation of CS cases in the municipalities of Bahia and the Local Spatial Association Indicator (LISA) was used to identify the formation of spatial regimes in the GeoDA software. Results: 8,786 cases of CS were registered in the period. An increasing growth in CS incidence, with a 511% increase between 2009 and 2018. Spatial autocorrelation was observed between the municipalities (I Moran = 0.452; p < 0.001) and four clusters were identified. More frequently, mothers were aged 20-29 years (50.7%); had incomplete primary education (54.9%); were Black and multiracial (93.2%); received prenatal care (82.2%); 49.0% were diagnosed with syphilis during prenatal care; 68.8% were not adequately treated, and 81.1% of their partners were not treated. Conclusion: The results showed that CS consolidates as a serious public health problem in Bahia, with an incidence 8.4 times higher in the period than the WHO target of 0.5/1,000 live births, predominantly related to inadequate prenatal care and social vulnerability indicators: young mothers with low education levels, as well as individuals identified as Black and multiracial. Thus, programs aimed at women of childbearing age and pregnant women need to be intensified.

Triatomine fauna in the state of Bahia, Brazil: What changed after 40 years of the vector-control program?

BACKGROUND: Neglected tropical diseases are a growing threat to global health, and endemic Chagas disease has emerged as one of the most important health problems in America. The main strategy to prevent Trypanosoma cruzi transmission is chemical control of vectors. This study presents a descriptive analysis of synanthropic triatomines before and after the implementation of a vector-control program in Bahia, Brazil. METHODS: Descriptive analysis and geospatial statistics were performed on triatomine data, (1) the relative abundance and (2) proportional spatial distribution, from Bahia during two periods: (A) 1957 to 1971 and (B) 2006 to 2019. RESULTS: We observed a decrease in the relative abundance of Panstrongylus megistus (A: n=22.032, 61.9%; B: n=1.842, 1.0%) and Triatoma infestans (A: n=1.310, 3.7%; B: n=763, 0.43%), as well as an increase in the relative abundance of T. sordida (A: n=8.314, 23.4%, B: n=146.901, 81.6%) and T. pseudomaculata (A: n=894, 2.5%, B: n=16.717, 9.3%). CONCLUSIONS: Our results indicate a clear reduction in the occurrence of P. megistus and T. infestans (last record in 2015) and an increase in the relative abundance and geographical distribution of T. sordida and T. pseudomaculata after 40 years of the vector-control program. The high frequency of other triatomine species in the municipalities of the state of Bahia and their abundance in recent years highlight the need to reinforce permanent entomological surveillance actions to prevent Chagas disease.

Triatomine fauna in the state of Bahia, Brazil: What changed after 40 years of the vector-control program?

ABSTRACT Background: Neglected tropical diseases are a growing threat to global health, and endemic Chagas disease has emerged as one of the most important health problems in America. The main strategy to prevent Trypanosoma cruzi transmission is chemical control of vectors. This study presents a descriptive analysis of synanthropic triatomines before and after the implementation of a vector-control program in Bahia, Brazil. Methods: Descriptive analysis and geospatial statistics were performed on triatomine data, (1) the relative abundance and (2) proportional spatial distribution, from Bahia during two periods: (A) 1957 to 1971 and (B) 2006 to 2019. Results: We observed a decrease in the relative abundance of Panstrongylus megistus (A: n=22.032, 61.9%; B: n=1.842, 1.0%) and Triatoma infestans (A: n=1.310, 3.7%; B: n=763, 0.43%), as well as an increase in the relative abundance of T. sordida (A: n=8.314, 23.4%, B: n=146.901, 81.6%) and T. pseudomaculata (A: n=894, 2.5%, B: n=16.717, 9.3%). Conclusions: Our results indicate a clear reduction in the occurrence of P. megistus and T. infestans (last record in 2015) and an increase in the relative abundance and geographical distribution of T. sordida and T. pseudomaculata after 40 years of the vector-control program. The high frequency of other triatomine species in the municipalities of the state of Bahia and their abundance in recent years highlight the need to reinforce permanent entomological surveillance actions to prevent Chagas disease.

Household rat infestation in urban slum populations: Development and validation of a predictive score for leptospirosis.

Domestic rats are the principal reservoir for urban leptospirosis. However, few studies have identified infestation markers in slums and evaluated their predictivity for leptospirosis risk. We compared households with leptospirosis cases in Salvador, Brazil between 2007 and 2009 and their neighbors using a case control design, surveying for rodent infestation signs and environmental characteristics. With the 2007-2008 data, a conditional logistic regression modeling identified the peridomiciliar presence of rodent burrows (OR, 3.30; 95% CI, 1.50-7.26), rat feces (2.86; 1.24-6.59), runs (2.57; 1.06-6.22), households bordering abandoned houses (2.48; 1.04-6.02), and unplastered walls (2.22; 1.02-6.02) as risk factors and developed a predictive score for leptospirosis. With an independent data set from 2009, a receiver operating characteristic (ROC) curve analysis evaluated the prediction score performance, with the area under the curve being 0.70 (95% CI, 0.64-0.76) for score development and 0.71 (0.65-0.79) for validation. Results indicate that high proportions of urban slum households are infested with R. norvegicus. The score performed well when identifying high-risk households within slums. These findings need confirmation in other urban centers, but suggest that community-based screening for rodent infestation can allow to target rodent and environmental control measures in populations at highest risk for leptospirosis.

Spatial and Simultaneous Seroprevalence of Anti-Leptospira Antibodies in Owners and Their Domiciled Dogs in a Major City of Southern Brazil.

Although leptospirosis has been considered a major concern in urban areas, no study to date has spatially and simultaneously compared both owner and dog serology in households of major cities. Accordingly, the aim of the present study was to assess the seroprevalence of Leptospira antibodies, evaluate associated risk factors and conduct spatial analyses in 565 randomly selected households, which included 597 dog owners and 729 dogs in Londrina, Southern Brazil. Seropositivity by MAT were detected in in 11/597 (1.84%) owners and in 155/729 (21.26%) dogs. The risk factors were evaluated with logistic regression analysis and spatial factors and case distribution were evaluated with kernel density analyses. The sera of 14/155 (9.03%) dogs reacted for more than one serovar with the same titer. Canicola was the most frequent serogroup, detected in 3/11 (27.27%) owners and 76/155 (49.03%) dogs. The highest titer among the owners was 1:3,200 and was detected in the same household with a titer of 1:800 in the dog. Simultaneous owner-dog seropositivity was found in 7/565 (1.23%) households, with three reacted against serogroup Canicola. Positive owners were detected in 4/565 (0.70%) households and positive dogs were detected in 141/565 (24.95%) households. The associated risks of infection for dogs were different from those associated with infection in owners. Risk analyses for Canicola also identified specific factors of infection. Regardless of owner and dog cases were not statistically clustered, the kernel map has shown dog positivity occurrence in the same hot locations and near positive owners. The dependent variable analysis and logit model suggested a greater likelihood of peri-domiciliary contact with Leptospira. In conclusion, exposure to Leptospira infection was significantly higher in dogs than in their owners and human cases spatially overlapped dog cases, implicating dogs as potential environmental sentinels for this disease. In addition, the associated risk may vary according to serogroup, and the observed simultaneous Canicola seropositivity of owner and dog has suggested intradomicile-transmitted infection.

Wide distribution of Trypanosoma cruzi-infected triatomines in the State of Bahia, Brazil.

BACKGROUND: The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is important to assess the potential risk of Chagas disease transmission. We identified T. cruzi infection and blood-meal sources of triatomines caught in and around houses in the state of Bahia, northeastern Brazil, and mapped the occurrence of infected triatomines that fed on humans and domestic animals. METHODS: Triatominae bugs were manually captured by trained agents from the Epidemiologic Surveillance team of Bahia State Health Service between 2013 and 2014. We applied conventional PCR to detect T. cruzi and blood-meal sources (dog, cat, human and bird) in a randomized sample of triatomines. We mapped triatomine distribution and analyzed vector hotspots with kernel density spatial analysis. RESULTS: In total, 5906 triatomines comprising 15 species were collected from 127 out of 417 municipalities in Bahia. The molecular analyses of 695 triatomines revealed a ~10% T. cruzi infection rate, which was highest in the T. brasiliensis species complex. Most bugs were found to have fed on birds (74.2%), and other blood-meal sources included dogs (6%), cats (0.6%) and humans (1%). Trypanosoma cruzi-infected triatomines that fed on humans were detected inside houses. Spatial analysis showed a wide distribution of T. cruzi-infected triatomines throughout Bahia; triatomines that fed on dogs, humans, and cats were observed mainly in the northeast region. CONCLUSIONS: Synanthropic triatomines have a wide distribution and maintain the potential risk of T. cruzi transmission to humans and domestic animals in Bahia. Ten species were recorded inside houses, mainly Triatoma sordida, T. pseudomaculata, and the T. brasiliensis species complex. Molecular and spatial analysis are useful to reveal T. cruzi infection and blood-meal sources in synanthropic triatomines, identifying areas with ongoing threat for parasite transmission and improving entomological surveillance strategies.

Seroprevalence of Trypanosoma cruzi infection among blood donors in the state of Bahia, Brazil.

INTRODUCTION: Chagas disease (CD) affects 5.7-7.0 million individuals worldwide, and its prevalence reached 25.1% in the state of Bahia, Brazil. There is an association between the prevalence of CD, the socioeconomic status of the population, and the risk of re-emergence due to non-vectorial transmission, such as blood transfusion. This study determined the seroprevalence of T. cruzi infection among blood donors in the state of Bahia, located in northeastern Brazil, and their epidemiological profile during a 10-year period. METHODS: We performed a descriptive cross-sectional study involving a database review. Data were collected from patients with non-negative results for T. cruzi infection during a 10-year period. RESULTS: A total of 3,084 (0.62%) samples were non-negative for T. cruzi infection in an initial serological screening, and 810 (0.16%) samples were non-negative in the second screening. The correlation between infection and age (30 years or older) and between infection and lower educational level (12 years or less) in the first and second screening was statistically significant. The seroprevalence of T. cruzi infection was higher in men in the first screening. In addition, 99.52% of the municipalities of Bahia had at least one case of CD. Livramento de Nossa Senhora and Salvador presented the highest disease prevalence and recurrence, respectively. CONCLUSIONS: The seroprevalence of T. cruzi infection in these populations was lower than that found in other studies in Brazil but was comparatively higher in densely-populated areas. The demographic characteristics of our population agreed with previous studies.

Seroprevalence of trypanosoma cruzi infection among blood donors in the state of Bahia, Brazil

Abstract INTRODUCTION: Chagas disease (CD) affects 5.7-7.0 million individuals worldwide, and its prevalence reached 25.1% in the state of Bahia, Brazil. There is an association between the prevalence of CD, the socioeconomic status of the population, and the risk of re-emergence due to non-vectorial transmission, such as blood transfusion. This study determined the seroprevalence of T. cruzi infection among blood donors in the state of Bahia, located in northeastern Brazil, and their epidemiological profile during a 10-year period. METHODS: We performed a descriptive cross-sectional study involving a database review. Data were collected from patients with non-negative results for T. cruzi infection during a 10-year period. RESULTS: A total of 3,084 (0.62%) samples were non-negative for T. cruzi infection in an initial serological screening, and 810 (0.16%) samples were non-negative in the second screening. The correlation between infection and age (30 years or older) and between infection and lower educational level (12 years or less) in the first and second screening was statistically significant. The seroprevalence of T. cruzi infection was higher in men in the first screening. In addition, 99.52% of the municipalities of Bahia had at least one case of CD. Livramento de Nossa Senhora and Salvador presented the highest disease prevalence and recurrence, respectively. CONCLUSIONS: The seroprevalence of T. cruzi infection in these populations was lower than that found in other studies in Brazil but was comparatively higher in densely-populated areas. The demographic characteristics of our population agreed with previous studies.

Frequent house invasion of Trypanosoma cruzi-infected triatomines in a suburban area of Brazil.

BACKGROUND: The demographic transition of populations from rural areas to large urban centers often results in a disordered occupation of forest remnants and increased economic pressure to develop high-income buildings in these areas. Ecological and socioeconomic factors associated with these urban transitions create conditions for the potential transmission of infectious diseases, which was demonstrated for Chagas disease. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 930 triatomines, mainly Triatoma tibiamaculata, collected in artificial and sylvatic environments (forests near houses) of a suburban area of the city of Salvador, Bahia State, Brazil between 2007 and 2011. Most triatomines were captured at peridomiciles. Adult bugs predominated in all studied environments, and nymphs were scarce inside houses. Molecular analyses of a randomly selected sub-sample (n=212) of triatomines showed Trypanosoma cruzi infection rates of 65%, 50% and 56% in intradomestic, peridomestic and sylvatic environments, respectively. We detected the T. cruzi lineages I and II and mixed infections. We also showed that T. tibiamaculata fed on blood from birds (50%), marsupials (38%), ruminants (7%) and rodents (5%). The probability of T. cruzi infection was higher in triatomines that fed on marsupial blood (odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.22-3.11). Moreover, we observed a protective effect against infection in bugs that fed on bird blood (OR = 0.43, 95% CI = 0.30-0.73). CONCLUSIONS/SIGNIFICANCE: The frequent invasion of houses by infected triatomines indicates a potential risk of T. cruzi transmission to inhabitants in this area. Our results reinforce that continuous epidemiological surveillance should be performed in areas where domestic transmission is controlled but enzootic transmission persists.

The relative contribution of immigration or local increase for persistence of urban schistosomiasis in Salvador, Bahia, Brazil.

Urbanization is increasing across the globe, and diseases once considered rural can now be found in urban areas due to the migration of populations from rural endemic areas, local transmission within the city, or a combination of factors. We investigated the epidemiologic characteristics of urban immigrants and natives living in a neighborhood of Salvador, Brazil where there is a focus of transmission of Schistosoma mansoni. In a cross-sectional study, all inhabitants from 3 sections of the community were interviewed and examined. In order to determine the degree of parasite differentiation between immigrants and the native born, S. mansoni eggs from stools were genotyped for 15 microsatellite markers. The area received migrants from all over the state, but most infected children had never been outside of the city, and infected snails were present at water contact sites. Other epidemiologic features suggested immigration contributed little to the presence of infection. The intensity and prevalence of infection were the same for immigrants and natives when adjusted for age, and length of immigrant residence in the community was positively associated with prevalence of infection. The population structure of the parasites also supported that the contribution from immigration was small, since the host-to-host differentiation was no greater in the urban parasite population than a rural population with little distant immigration, and there had been little differentiation in the urban population over the past 7 years. Public health efforts should focus on eliminating local transmission, and once eliminated, reintroduction from distant migration is unlikely.

Influence of household rat infestation on leptospira transmission in the urban slum environment.

BACKGROUND: The Norway rat (Rattus norvegicus) is the principal reservoir for leptospirosis in many urban settings. Few studies have identified markers for rat infestation in slum environments while none have evaluated the association between household rat infestation and Leptospira infection in humans or the use of infestation markers as a predictive model to stratify risk for leptospirosis. METHODOLOGY/PRINCIPAL FINDINGS: We enrolled a cohort of 2,003 urban slum residents from Salvador, Brazil in 2004, and followed the cohort during four annual serosurveys to identify serologic evidence for Leptospira infection. In 2007, we performed rodent infestation and environmental surveys of 80 case households, in which resided at least one individual with Leptospira infection, and 109 control households. In the case-control study, signs of rodent infestation were identified in 78% and 42% of the households, respectively. Regression modeling identified the presence of R. norvegicus feces (OR, 4.95; 95% CI, 2.13-11.47), rodent burrows (2.80; 1.06-7.36), access to water (2.79; 1.28-6.09), and un-plastered walls (2.71; 1.21-6.04) as independent risk factors associated with Leptospira infection in a household. We developed a predictive model for infection, based on assigning scores to each of the rodent infestation risk factors. Receiver operating characteristic curve analysis found that the prediction score produced a good/excellent fit based on an area under the curve of 0.78 (0.71-0.84). CONCLUSIONS/SIGNIFICANCE: Our study found that a high proportion of slum households were infested with R. norvegicus and that rat infestation was significantly associated with the risk of Leptospira infection, indicating that high level transmission occurs among slum households. We developed an easily applicable prediction score based on rat infestation markers, which identified households with highest infection risk. The use of the prediction score in community-based screening may therefore be an effective risk stratification strategy for targeting control measures in slum settings of high leptospirosis transmission.

Avaliação ambiental e do gradiente social nas infecções por leptospira em uma comunidade de Salvador-Bahia / Environmental and social gradient on leptospira infection in a community assessment of Salvador-Bahia

Introdução: A leptospirose tem emergido como um importante problema de saúde pública no mundo. Esta zoonose é responsável por epidemias anuais que acometem principalmente indivíduos residentes em comunidades negligenciadas como as existentes em Salvador. Poucos estudos longitudinais foram realizados com objetivo de identificar os fatores de risco para infecção, fontes de transmissão e compreender a real dimensão da leptospirose nessas comunidades. Objetivo: Identificar fatores de risco para infecção prévia e novas infecções por leptospiras no contexto ambiental e socioeconômico em uma comunidade em Salvador Bahia. Métodos: Estudos de soroprevalência e coorte foram conduzidos na comunidade de Pau da Lima, com a realização de entrevistas domiciliares, avaliação peridomiciliar, coleta de material biológico e análises espaciais para mensurar a associação epidemiológica entre fatores de risco ambientais e as infecções. O teste de microaglutinação foi utilizado para avaliar amostras sorológicas obtidas. Resultados: Residir próximo aos esgotos abertos e do fundo do vale proximidade do domicílio a acúmulo de lixo e baixa renda foram associados com as infecções. A incidência anual de infecções secundárias foi de 2,3 vezes maior que as infecções primárias. Conclusão: O presente estudo sugere que medidas preventivas devem focalizar nas deficiências de infraestrutura que servem como fontes de transmissão. Intervenções mais efetivas precisam se concentrar especialmente nos adultos jovens e nos grupos populacionais mais desfavorecidos nestas comunidades.

Introduction: Leptospirosis has emerged as an important public health problem in the world. This zoonosis is responsible for annual epidemics affecting mainly individuals living in disadvantaged communities as existing in Salvador. Few longitudinal studies have been conducted in order to identify risk factors for infection, transmission sources and understand the real dimension of leptospirosis in these communities. Objective: To identify risk factors for early infection and new infections by Leptospira in environmental and socioeconomic context in a community in Salvador Bahia. Methods: Seroprevalence and cohort studies were conducted in Pau da Lima community, conducting home interviews peridomicilary review, collection of biological material and spatial analysis to measure the epidemiological association between environmental risk factors and infections. The agglutination test was used to evaluate serum samples obtained. Results: Residing next to open sewers and the valley floor near the homes of waste accumulation and low income were associated with infections. The annual incidence of secondary infections was 2.3 times higher than primary infections. Conclusion: This study suggests that preventive measures should focus on infrastructure deficiencies that serve as sources of transmission. More effective interventions need to focus especially on young adults and the most disadvantaged population groups in these communities.

Genetic population structure of cercariae from an urban foci of Schistosoma mansoni, Brazil.

Rapid urbanization in Brazil has meant that many persons from rural areas where Schistosoma mansoni is endemic have migrated to cities. Discovery of a focus of active transmission in the city of Salvador prompted a citywide survey for active and potential transmission sites. Cercariae shed from infected snails collected from four locations were used to determine how these samples were related and if they were representative of the parasite population infecting humans. Each cercarial collection was greatly differentiated from the others, and diversity was significantly lower when compared with eggs from natural human infections in one site. Egg samples collected 7 years apart in one neighborhood showed little differentiation (Jost's D = 0.01-0.03). Given the clonal nature of parasite reproduction in the snail host and the short-term acquisition of parasites, cercariae from collections at one time point are unlikely to be representative of the diversity in the human population.

[Geographical distribution of leptospirosis in Aracaju, State of Sergipe from 2001 to 2007]. / Espacialização da leptospirose em Aracaju, Estado de Sergipe, no período de 2001 a 2007.

INTRODUCTION: Leptospirosis, a disease caused by pathogenic spirochetes of the genus Leptospira, is one of the most widespread zoonoses in the world and is considered an important public health problem. This paper aims to describe the spatial pattern of leptospirosis in the City of Aracaju from 2001 to 2007 in an effort to identify areas at risk for leptospirosis. METHODS: We used the ratio of Kernel, which represents the ratio between two surfaces, to visualize the surface of disease risk. The numerator corresponds to the number of cases geocoded to the census tract, and the denominator of the kernel corresponds to the population of these areas. Using this method, the areas with the highest density of cases were delineated and compared visually with socioeconomic factors, such as average income. RESULTS: The spatial pattern was different in periods of rain compared with periods of drought and did not coincide with the areas considered most at risk for the disease. This study revealed the importance of applying spatial analysis techniques in the field of public health. CONCLUSIONS: These findings indicate that the kernel is a useful tool for obtaining a comprehensive review of the epidemiology of leptospirosis in Aracaju, which supports the kernel's use by the municipal health departments and by the state.

Espacialização da leptospirose em Aracaju, Estado de Sergipe, no período de 2001 a 2007 / Geographical distribution of leptospirosis in Aracaju, State of Sergipe from 2001 to 2007

INTRODUÇÃO: A leptospirose, enfermidade causada por uma espiroqueta patogênica do gênero Leptospira, é uma das zoonoses mais difundidas no mundo, considerada um importante problema de saúde pública. Este trabalho tem como objetivo descrever o padrão espacial da leptospirose na Cidade de Aracaju, no período de 2001 a 2007, buscando identificar as áreas de risco para ocorrência da leptospirose. MÉTODOS: Utilizou-se a razão de Kernel, que consiste na criação de uma razão entre duas superfícies, para visualizar a superfície de risco da doença, onde no numerador coloca-se os casos, georreferenciados para setor censitário, e no denominador o kernel da população dessas áreas. Através deste método, foi possível delimitar áreas de maior densidade de casos, e compará-las visualmente com fator socioeconômico, como renda média. RESULTADOS: Comparando os períodos de chuva com os períodos de seca, verificou-se que não ocorre a presença de padrão espacial semelhante nos dois períodos, não coincidindo com as áreas consideradas de maior risco para ocorrência da doença. Através dos parâmetros estabelecidos, neste estudo, foi permitido verificar a importância da aplicação de técnicas de análise espacial na área de saúde pública. CONCLUSÕES: O kernel se mostrou uma ferramenta útil na obtenção de uma análise global da situação epidemiológica da leptospirose em Aracaju, o que viabiliza sua utilização pelas secretarias de saúde municipal e estadual.

INTRODUCTION: Leptospirosis, a disease caused by pathogenic spirochetes of the genus Leptospira, is one of the most widespread zoonoses in the world and is considered an important public health problem. This paper aims to describe the spatial pattern of leptospirosis in the City of Aracaju from 2001 to 2007 in an effort to identify areas at risk for leptospirosis. METHODS: We used the ratio of Kernel, which represents the ratio between two surfaces, to visualize the surface of disease risk. The numerator corresponds to the number of cases geocoded to the census tract, and the denominator of the kernel corresponds to the population of these areas. Using this method, the areas with the highest density of cases were delineated and compared visually with socioeconomic factors, such as average income. RESULTS: The spatial pattern was different in periods of rain compared with periods of drought and did not coincide with the areas considered most at risk for the disease. This study revealed the importance of applying spatial analysis techniques in the field of public health. CONCLUSIONS: These findings indicate that the kernel is a useful tool for obtaining a comprehensive review of the epidemiology of leptospirosis in Aracaju, which supports the kernel's use by the municipal health departments and by the state.

[Identification of schistosomiasis risk areas using spatial analysis in Lauro de Freitas, Bahia State, Brazil]. / Análises espaciais na identificação das áreas de risco para a esquistossomose mansônica no município de Lauro de Freitas, Bahia, Brasil.

The spread of schistosomiasis mansoni defies efforts by Brazil's Unified National Health System, thus demonstrating the need to reassess endemic control programs in the country. The aim of this study was to demarcate geographic areas at risk of schistosomiasis in Lauro de Freitas, Bahia State, Brazil, and to establish the epidemiological and socioeconomic profile of the disease in this municipality (county). Kernel density estimator exploratory analysis was used for visual identification of areas at risk. Kulldorff & Nagarwalla's spatial analysis was used to obtain statistically significant clusters and to measure risk. These technologies identified four risk areas for schistosomiasis. Clusters identified within the risk areas were characterized by lower socioeconomic conditions. Multiple correspondence analyses showed a distinct profile for positive patients in the primary cluster. The techniques employed here represent an important methodological acquisition for tracking and controlling schistosomiasis in Lauro de Freitas.

Análises espaciais na identificação das áreas de risco para a esquistossomose mansônica no município de Lauro de Freitas, Bahia, Brasil / Identification of schistosomiasis risk areas using spatial analysis in Lauro de Freitas, Bahia State, Brazil

A disseminação da esquistossomose mansônica vem desafiando o sistema de saúde brasileiro, deixando clara a necessidade da reavaliação das estratégias do programa de controle da endemia. O objetivo deste trabalho foi delimitar as áreas geográficas de risco para a esquistossomose em Lauro de Freitas, Bahia, Brasil, e estabelecer o perfil epidemiológico e socioeconômico da doença no município. Utilizou-se o estimador de densidade de Kernel para a identificação visual de aglomerados de casos e a análise de varredura espaço-temporal de Kulldorff & Nagarwalla para a obtenção de aglomerados com significância estatística e mensuração do risco. As duas técnicas identificaram quatro áreas de risco para a doença no município, com indicadores socioeconômicos mais baixos que as áreas fora dos aglomerados. A análise de correspondência múltipla mostrou um perfil diferenciado nos pacientes positivos para a esquistossomose pertencentes ao aglomerado primário. As técnicas empregadas se configuram em uma importante aquisição metodológica para a vigilância e controle da doença no município.

The spread of schistosomiasis mansoni defies efforts by Brazil's Unified National Health System, thus demonstrating the need to reassess endemic control programs in the country. The aim of this study was to demarcate geographic areas at risk of schistosomiasis in Lauro de Freitas, Bahia State, Brazil, and to establish the epidemiological and socioeconomic profile of the disease in this municipality (county). Kernel density estimator exploratory analysis was used for visual identification of areas at risk. Kulldorff & Nagarwalla's spatial analysis was used to obtain statistically significant clusters and to measure risk. These technologies identified four risk areas for schistosomiasis. Clusters identified within the risk areas were characterized by lower socioeconomic conditions. Multiple correspondence analyses showed a distinct profile for positive patients in the primary cluster. The techniques employed here represent an important methodological acquisition for tracking and controlling schistosomiasis in Lauro de Freitas.

Tecnologias de geoprocessamento no estudo dos acidentes escorpiônicos na cidade de Salvador, Bahia / Geoprocessing technologies in the study of scorpionism outbreak in Salvador, BA

Foram analisados 205 casos de acidentes ocasionados por escorpiões ocorridos na cidade de Salvador,BA, registrados pelo Centro de Informações Antiveneno-CIAVE -BA, no período de 1999 a 2000, com objetivo de testar a viabilidade do uso de tecnologias de geoprocessamento, na detecção de grupos populacionais prioritários para a alocação de recursos dos serviços de saúde, visando a dinamização dos processos de controle desses agravos à saúde. O SIG proporcionou o georreferenciamento dos exatos locais da ocorrência dos acidentes escorpiônicos, permitindo a identificação e delimitação das áreas de maior concentração (clusters), representadas pelas ZI 006 e ZI 007, que correspondem aos bairros de Nordeste de Amaralina, Vale das Pedrinhas e Alto de Santa Cruz. Os resultados obtidos indicaram, também, que o escorpionismo está urbanizado e que a sua maior ocorrência está relacionada ao intradomicílio em áreas de maior densidade demográfica. As técnicas de geoprocessamento, seguindo a metodologia do enfoque de risco, possibilitaram a classificação do espaço geográfico em áreas endêmicas (ZI 006 E 007) e de risco (ZI 069, 063, 046 e 037)para os acidentes escorpiônicos na cidade de Salvador,BA. Tais resultados nos levam a inferir que a utilização dessas tecnologias nas tomadas de decisões e nas formulações de campanhas de controle, essenciais às ações do setor saúde, possibilitarão a agilização das atividades de combate desse artrópodo quando da incorporação da distribuição espacial dos eventos.