Due to the persistence of dengue and other arbovirus infections in Brazil, the government has stepped up measures to combat the Aedes aegypti mosquito vector. The responsibilities of community endemic disease workers (CEDW) and community health workers (CHW) include acting as intermediaries and disseminating knowledge in the community. The aim of this study was to analyze knowledge and practices in dengue control by different social subjects: residents and CEDW/CHW. Interviews were held with residents, field and mobilization CEDW, and CHW in two neighborhoods in Salvador, Bahia State, using focus groups. Residents expressed uncertainty on the form of transmission and hazards of dengue. Field CEDW voiced conflicting feelings due to the need to inform the community on issues over which they lack any control, while expressing personal dissatisfaction with their work and a feeling of underappreciation due to their lack of training. Mobilization CEDW blamed the population and emphasized their own importance as the solution to dengue control. CHW failed to reflect their field experience in their discourse and felt they had no responsibility over vector control. All the groups agreed that government is to blame for dengue and that the solution lies in education. There is an evident need for regular educational interventions, based on dialogue and awareness-raising to deal with residents' daily reality, drawing individuals (residents and CHW) into the knowledge-building process. Under the prevailing methodology, the dissemination of information and knowledge is insufficient to promote community improvements for dengue control.

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.

RESUMONa região do Subúrbio Ferroviário da Cidade do Salvador (Bahia, Brasil), foram relatados casos de esquistossomose, e isso motivou este estudo de prevalência em 268 escolares residentes em um dos seus bairros (São Bartolomeu). Em 30,2% das crianças, o exame parasitológico (Kato-Katz) foi positivo, com carga parasitária entre 24 a 2.160 ovos de Schistosoma mansoni/g de fezes, predominando entre os meninos e nos maiores de 10 anos de idade. Nas crianças com residências mais próximas das coleções naturais de água, ocorreu maior freqüência de eliminadores de ovos e nela residiam os três únicos casos com a forma hepatosplênica da esquistossomose. Também, todas as 81 crianças com ovos de Schistosoma mansoni nas fezes nasceram e sempre residiram na área de estudo. Como nesse bairro há todos os elementos da cadeia epidemiológica do Schistosoma mansoni, são fortes as evidências da transmissão urbana dessa infecção. Palavras-chaves: Esquistossomose mansônica. Transmissão urbana. Escolares. Salvador. Bahia. ABSTRACTIn the Subúrbio Ferroviário region of Salvador (Bahia, Brasil) occurrences of schistosomiasis were found. This fact motivated the investigation of the prevalence of the eggs in a group of 268 resident students in one of its neighborhoods (São Bartolomeu). The parasitological test analyzed by the Kato-Katz methodology, showed positive results in 30.2% of the children, ranging from 24 to 2,160 eggs Schistosoma mansoni/gram of feces. Infection was predominant in boys and in those 10 years old and over. Observation revealed that infection predominated in children that live close to natural water bodies. This region was where the three registered cases of hepatosplenicos occurred. Moreover, all the 81 children infected with Schistosoma mansoni eggs were born and live in the study area. Since this neighborhood presents all the elements of the epidemiological chain of Schistosoma mansoni, the evidences strongly suggests the urban transmission of this infection.

Many parasite populations are difficult to sample because they are non-uniformly distributed between several host species and are often not easily collected from the living host, limiting sample size and possibly distorting the representation of the population. For the parasite Schistosoma mansoni, we investigated the use of the aggregated eggs found in the stool of infected individuals as a simple and representative sample. Previously, we demonstrated that microsatellite allele frequencies can be accurately estimated from pooled DNA of cloned S. mansoni adults, and we show here that genotyping parasite populations from reproductively isolated laboratory strains can be used to identify these specific populations based on characteristic patterns of allele frequencies, as observed by polyacrylamide gel electrophoresis and automated sequencer analysis of fluorescently labeled PCR products. In addition, microsatellites used to genotype aggregates of eggs collected from stools of infected individuals produced results consistent with the geographic distribution of the samples. Direct analysis of total stool eggs can be an important approach to questions of population genetics for this parasite by increasing the sample size to thousands per individual and reducing bias.

Abstract. Environmental changes have a strong influence on the emergence and/or reemergence of infectious diseases. The city of Salvador, Brazil -currently the focus of a housing boom linked to massive deforestation-is an example in point as the destruction of the remaining areas of the Atlantic Forest around the city has led to an increased risk for Chagas disease. Human domiciles have been invaded by the triatomine vectors of Trypansoma cruzi, the flagellate protozoan causing Chagas disease, a problem of particular concern in urban/suburban areas of the city such as the Patamares sector in the north-east, where numbers of both the vector and human cases of the disease have increased lately. To control and prevent further deterioration of the situation, the control programme for Chagas disease, developed by the Bahia Center for Zoonosis Control, has divided the area into a grid of designated surveillance units (ZIs) that are subjected to vector examination. In six out of 98 of these ZIs, 988 triatomes were collected and georeferenced during the 3-year period between 2006 and 2009. The hottest months, that are also generally the driest, showed the highest numbers of triatomines with Triatoma tibiamaculata being the predominant species (98.3%) with Panstrongylus geniculatus present only occasionally (0.6%). Fifty-four percent of all triatomines captured were found inside the homes, and 48.6% out of 479 individuals in the affected ZIs selected for analysis tested positive for T. cruzi infection. The study presented here is a pioneering initiative to map the spatial distribution of triatomines based on geographical information systems with the additional aim of contributing to an expanded knowledge-base about T. cruzi and its vectors in urban areas and raise public health awareness of the risks involved.

Abstract. 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.

To understand the occurrence of the Congenital Zika Syndrome (CZS), the living conditions of pregnant individuals must be considered in order to identify factors and areas of risk. An intersectional approach provides an understanding of the vulnerabilities to which Black women are subjected. To that end, we present an overview of the spatio-temporal distribution of confirmed cases of microcephaly associated with CZS during the 2015-2016 period in Salvador, Bahia, Brazil based on a survey of Black and Caucasian, pregnant women seen through the intersectional lens of race and class. To consider the confirmed cases of microcephaly and other neurological anomalies associated with CZS, a Living Condition Index (LCI) was utilized to rate the socio-environmental vulnerability of pregnant women. There was less information in the notification records with regard to Black, pregnant women resulting in fewer examinations. Twelve, highrisk areas for Black, pregnant women were identified but only two for Caucasian women. CZS cases referred to Black, pregnant women were found to be concentrated in census sectors with a low (31.6%) and very low (34.5%) LCI, while those referred to Caucasian, pregnant women were concentrated in areas with a high (35.6%) and intermediate (29.4%) LCI. The study concludes that inequities in health expose different population groups to different forms of illnesses, and institutional racism solidifies scenarios of exclusion. In this sense, Black women experiences manifest directly in their health. Confrontation with arboviruses requires the implementation of inter-institutional policies aimed at overcoming discriminatory practices of exposure.

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