The present work reports on two epidemiological episodes resulting in acute schistosomiasis involving wealthy persons living in the State of Pernambuco, Brazil. The authors discuss the epidemiological, clinical and serologic characteristics of the acute infections and also the way in which the conditions for transmission occurred.

Espera-se que os grandes avanços da pesquisa de genomas alcancem saltos visíveis para a sobrevivência da humanidade dentro do contexto de sustentabilidade global. Vemos atualmente a necessidade imediata de incrementar a produção de alimentos e melhorar a qualidade de vida e saúde humana, mantendo a biodiversidade preservada. A biotecnologia é a utilização racional das ferramentas geradas pela biologia molecular e genética moderna que, dado ao grande avanço dessas áreas, poderá em breve responder essas novas questões. Este trabalho, escrito por três gerações de pesquisadores, inicia com uma perspectiva histórica da pesquisa biomédica em doenças parasitárias nos últimos séculos em nosso país. Em seguida, descrevemos os mais recentes avanços da biologia molecular e genética genômica. Ressaltamos a importância dessas novas conquistas dentro de uma prospecção da pesquisa biomédica deste século e seus possíveis impactos na saúde humana.

We all hope that biotechnology will answer some social and economical unavoidable requirements of the modern life. It is necessary to improve agriculture production, food abundance and health quality in a sustainable development. It is indeed a hard task to keep the progress on taking into account the rational use of genetic resources and the conservation of biodiversity. In this context, a historical perspective and prospects of the biomedical research on parasitic diseases is described in a view of three generations of investigators. This work begins with a picture of the scientific progress on biomedical research and human health over the last centuries. This black-and-white picture is painted by dissecting current advancements of molecular biology and modern genetics, which are outlined at the meaning of prospecting achievements in health science for this new millenium.

Este trabalho notifica a ocorrência de um surto de esquistossomose aguda na praia de Porto de Galinhas, Pernambuco, Brasil, quando 662 pessoas tiveram diagnóstico positivo para Schistosoma mansoni. A infecção humana em massa ocorreu no feriado de 7 de setembro, quando chuvas pesadas provocaram a enchente do rio Ipojuca que invadiu as residências. A maioria dos casos agudos foi representada por famílias de residentes locais que tiveram exposição diária às cercárias durante três semanas, até que as águas baixassem. O inquérito malacológico aponta para a possibilidade dos caramujos vetores terem sido introduzidos na localidade com os aterros realizados em quintais, onde vieram a se reproduzir em criadouros peridomiciliares. A infecção dos moluscos se deu a partir de vazamentos de fossas. Os resultados da clínica e do laboratório apontam para cerca de 62% de casos agudos. Estudos complementares estão sendo realizados, para a melhor compreensão deste evento epidemiológico de significativa magnitude para os órgãos de saúde pública e impacto para a população afetada.

We recently confirmed several cases of acute schistosomiasis in Porto de Galinhas beach, Northeast Brazil. A total of 662 patients were diagnosed by parasitological and clinical examinations. The infection likely occurred during the September 7 national holiday, when heavy rainfall flooded the Ipojuca River and people were infected when the water covered their yards. Families were continuously exposed to infection for a period of three weeks until the water had completely dried up. Previous investigation suggests that snail vectors were introduced as a result of landfill in marshy areas. The swamp-flooding of such areas facilitated the emergence of slums surrounded by snail breeding sites. Heavy rainfall caused open-air sewage ditches to overflow, allowing for infection of snails by Schistosoma mansoni. Thus, continuous floods were responsible for the spread of human infection. Clinical and laboratory results identified 62% of acute cases of S. mansoni. Complementary studies are being conducted to define the impact and epidemiological meaning of the acute schistosomiasis outbreak.

Este trabalho notifica a ocorrência de um surto de esquistossomose aguda na praia de Porto de Galinhas, Pernambuco, Brasil, quando 662 pessoas tiveram diagnóstico positivo para Schistosoma mansoni. A infecção humana em massa ocorreu no feriado de 7 de setembro, quando chuvas pesadas provocaram a enchente do rio Ipojuca que invadiu as residências. A maioria dos casos agudos foi representada por famílias de residentes locais que tiveram exposição diária às cercárias durante três semanas, até que as águas baixassem. O inquérito malacológico aponta para a possibilidade dos caramujos vetores terem sido introduzidos na localidade com os aterros realizados em quintais, onde vieram a se reproduzir em criadouros peridomiciliares. A infecção dos moluscos se deu a partir de vazamentos de fossas. Os resultados da clínica e do laboratório apontam para cerca de 62% de casos agudos. Estudos complementares estão sendo realizados, para a melhor compreensão deste evento epidemiológico de significativa magnitude para os órgãos de saúde pública e impacto para a população afetada.

We recently confirmed several cases of acute schistosomiasis in Porto de Galinhas beach, Northeast Brazil. A total of 662 patients were diagnosed by parasitological and clinical examinations. The infection likely occurred during the September 7 national holiday, when heavy rainfall flooded the Ipojuca River and people were infected when the water covered their yards. Families were continuously exposed to infection for a period of three weeks until the water had completely dried up. Previous investigation suggests that snail vectors were introduced as a result of landfill in marshy areas. The swamp-flooding of such areas facilitated the emergence of slums surrounded by snail breeding sites. Heavy rainfall caused open-air sewage ditches to overflow, allowing for infection of snails by Schistosoma mansoni. Thus, continuous floods were responsible for the spread of human infection. Clinical and laboratory results identified 62% of acute cases of S. mansoni. Complementary studies are being conducted to define the impact and epidemiological meaning of the acute schistosomiasis outbreak.

INTRODUÇÃO: Em 1988, 22 casos autóctones de esquistossomose foram registrados na Praia do Forte Orange, ilha de Itamaracá, Pernambuco. Todos os casos ocorreram em indivíduos de classe média/alta que veraneavam na ilha. Foi realizado estudo com o objetivo de identificar e caracterizar criadouros/focos de vetores da esquistossomose na localidade, correlacionando os determinantes biológicos da doença com o contexto ambiental da sua ocorrência. MÉTODOS: Foram levantados dados secundários para resgatar as características ambientais da área antes da ocupação humana. O inquérito malacológico teve a duração de um ano com mapeamento da área, coleta mensal e exame dos moluscos. RESULTADOS/CONCLUSÕES: Em 1 km de extensão da praia, foram identificados 20 criadouros e demarcadas 28 estações de coleta. Os resultados mostram a variação mensal da densidade populacional de moluscos e das taxas de infecção, correlacionados com sazonalidade e tipos de criadouros. Destaca-se a importância desse novo perfil epidemiológico da esquistossomose em Pernambuco, relacionando o modo de ocupação daquele espaço com o estabelecimento de sítios de transmissão ativa da esquistossomose.

INTRODUCTION: In 1988, 22 autochthonous cases from accidental exposure were registered in Forte Orange beach, Itamaracá Island, Pernambuco, Brazil. All cases occurred in middle-to-upper class individuals who were vacationing in the island. After the cases were identified, the major objective was to find breading sites of schistosomiasis vectors and correlate the biological factors with the environmental conditions. METHODS: The environmental characteristics of the beach before human occupation were obtained from several documents. Also, a one-year malacological survey was conducted with monthly collection of mollusks, and the determination of their infectivity rates. RESULTS/CONCLUSIONS: The malacological survey was able to identify 20 breading sites of Biomphalaria glabrata and 28 capture station were set up. Snails were collected and examined each month throughout a whole year. The results show a seasonal variation in the mollusk population density associated with infection rates and types of breading sites. The importance of this new epidemiological profile of schistosomiasis in the State of Pernambuco relies on the fact that it can be related with the drastic human interference on the environment. Ecological, environmental, and demographic factors as well as the epidemiological characteristics of the disease have social and economic repercussions.

INTRODUÇÃO: Em 1988, 22 casos autóctones de esquistossomose foram registrados na Praia do Forte Orange, ilha de Itamaracá, Pernambuco. Todos os casos ocorreram em indivíduos de classe média/alta que veraneavam na ilha. Foi realizado estudo com o objetivo de identificar e caracterizar criadouros/focos de vetores da esquistossomose na localidade, correlacionando os determinantes biológicos da doença com o contexto ambiental da sua ocorrência. MÉTODOS: Foram levantados dados secundários para resgatar as características ambientais da área antes da ocupação humana. O inquérito malacológico teve a duração de um ano com mapeamento da área, coleta mensal e exame dos moluscos. RESULTADOS/CONCLUSÕES: Em 1 km de extensão da praia, foram identificados 20 criadouros e demarcadas 28 estações de coleta. Os resultados mostram a variação mensal da densidade populacional de moluscos e das taxas de infecção, correlacionados com sazonalidade e tipos de criadouros. Destaca-se a importância desse novo perfil epidemiológico da esquistossomose em Pernambuco, relacionando o modo de ocupação daquele espaço com o estabelecimento de sítios de transmissão ativa da esquistossomose.

INTRODUCTION: In 1988, 22 autochthonous cases from accidental exposure were registered in Forte Orange beach, Itamaracá Island, Pernambuco, Brazil. All cases occurred in middle-to-upper class individuals who were vacationing in the island. After the cases were identified, the major objective was to find breading sites of schistosomiasis vectors and correlate the biological factors with the environmental conditions. METHODS: The environmental characteristics of the beach before human occupation were obtained from several documents. Also, a one-year malacological survey was conducted with monthly collection of mollusks, and the determination of their infectivity rates. RESULTS/CONCLUSIONS: The malacological survey was able to identify 20 breading sites of Biomphalaria glabrata and 28 capture station were set up. Snails were collected and examined each month throughout a whole year. The results show a seasonal variation in the mollusk population density associated with infection rates and types of breading sites. The importance of this new epidemiological profile of schistosomiasis in the State of Pernambuco relies on the fact that it can be related with the drastic human interference on the environment. Ecological, environmental, and demographic factors as well as the epidemiological characteristics of the disease have social and economic repercussions.

Este artigo é parte de um estudo mais amplo que empregou abordagens epidemiológica e antropológica para procurar entender a produção e manutenção da esquistossomose em pequena comunidade de área endêmica de Pernambuco. No presente trabalho, realizamos um estudo de corte transversal para avaliação dos fatores de risco para esquistossomose, associando variáveis sócio-econômicas, sanitárias e comportamentais (quantificáveis), com a prevalência e intensidade da infecção. Uma análise estatística univariada selecionou três variáveis (faixa etária, escolaridade e número de contatos), que mostraram associação significativa com a positividade para S. mansoni. Os resultados da análise multivariada realizada a seguir permitiram a identificação dos fatores causais e das variáveis de confundimento, entre aquelas anteriormente selecionadas. O diagnóstico epidemiológico quantitativo é discutido criticamente, com embasamento no estudo qualitativo etnográfico, quanto às condições ambientais de risco (contaminação, transmissão) e práticas de risco (atividades econômicas e comportamentais).

This article is part of a larger study in which epidemiological and anthropological methods were used to help understand the production and maintenance of schistosomiasis in a small endemic area in Pernambuco State. A cross-sectional study identified several local risk factors for schistosomiasis, quantifying socioeconomic, sanitary, and behavioral variables and then relating them to the prevalence and intensity of schistosomiasis infection. Using univariate analysis, three variables (age group, schooling, and human/water contact) showed significant association with S. mansoni infection. Causal factors and confounding variables were identified through multivariate analysis. Quantitative epidemiological analysis is critically discussed regarding a qualitative ethnographic study in relation to environmental risk situations (contamination and transmission) as well as risk practices (economic and behavioral).

Este artigo é parte de um estudo mais amplo que empregou abordagens epidemiológica e antropológica para procurar entender a produção e manutenção da esquistossomose em pequena comunidade de área endêmica de Pernambuco. No presente trabalho, realizamos um estudo de corte transversal para avaliação dos fatores de risco para esquistossomose, associando variáveis sócio-econômicas, sanitárias e comportamentais (quantificáveis), com a prevalência e intensidade da infecção. Uma análise estatística univariada selecionou três variáveis (faixa etária, escolaridade e número de contatos), que mostraram associação significativa com a positividade para S. mansoni. Os resultados da análise multivariada realizada a seguir permitiram a identificação dos fatores causais e das variáveis de confundimento, entre aquelas anteriormente selecionadas. O diagnóstico epidemiológico quantitativo é discutido criticamente, com embasamento no estudo qualitativo etnográfico, quanto às condições ambientais de risco (contaminação, transmissão) e práticas de risco (atividades econômicas e comportamentais).

This article is part of a larger study in which epidemiological and anthropological methods were used to help understand the production and maintenance of schistosomiasis in a small endemic area in Pernambuco State. A cross-sectional study identified several local risk factors for schistosomiasis, quantifying socioeconomic, sanitary, and behavioral variables and then relating them to the prevalence and intensity of schistosomiasis infection. Using univariate analysis, three variables (age group, schooling, and human/water contact) showed significant association with S. mansoni infection. Causal factors and confounding variables were identified through multivariate analysis. Quantitative epidemiological analysis is critically discussed regarding a qualitative ethnographic study in relation to environmental risk situations (contamination and transmission) as well as risk practices (economic and behavioral).

This study focuses on the possibility of experimental hybridization among host snail species for Schistosoma mansoni in Brazil, with morphological characterization of the hybrids found. By using albinism as a genetic marker, intraspecific crossbreedings were performed between two strains of each species involved, in addition to interspecific crossbreedings; the only viable crossbreeding was between pigmented Biomphalaria glabrata (Paulista, PE) and albino B. tenagophila (Joinville, SC), with the formation of F1 and F2 generations. All offspring in F1 displayed black eyes and a renal ridge on the mantle, while F2 displayed dissociated morphological traits. With regard to reproduction, F1 was more efficient than F2. The experiment's results suggest post-zygotic reproductive isolation.

A esquistossomose continua a ser um problema de saúde pública no Nordeste do Brasil embora o emprego, em larga escala, da quimioterapia venha sendo apontado como um dos fatores responsáveis pela redução das formas graves. O Estado de Pernambuco vem apresentando taxas crescentes de infecção humana para esquistossomose com perfil epidemiológico de prevalências crônicas (até 80%) na região rural e casos recentes de infecção aguda no litoral. Discute-se a reprodução e expansão da esquistossomose a partir de uma concepção estrutural e histórica de causas, onde se inserem fatores não só de ordem biológica mas também sociais, políticos e culturais que vêm contribuindo para a formação dos quadros endêmicos: a forma de ocupação e do uso da terra, desemprego, desnutrição, migração e outros. Questionam-se as crescentes dificuldades para o controle da doença e o papel da investigação epidemiológica na compreensão da essência social do processo saúde/doença.

Schistosomiasis mansoni can be considered an important public health problem in Northeastern Brazil, in spite of the reduction in the prevalence of the hepatosplenic clinical forms which have been attributed to the large scale use of chemotherapy in this country. However, the rise in the prevalence rates and the spread of this endemic disease to new areas show that schistosomiasis is assuming its must cruel expression: less lethal but more greatly incapacitating in terms of irreversible physical and moral damage to human beings. The state of Pernambuco presents growing rates for schistosomiasis infection in humans. The epidemiological profile of this disease displays high and consistent prevalence rates (up to 80%) in rural areas, and new cases of acute infection on the coast, where schistosomiasis has recently been introduced. The reproduction and expansion of this endemic disease can be better understood on the basic of a conception of structural and historical causation. The disease construction process should be reconstructed in the light of biological as well as the social, political and cultural factors which are jointly responsible for the present endemic situation. Within that frame work, the historical and socio-economic features that interact with the parasite and give rise to the present proportions of the schistosomiasis epidemic in Pernambuco are discussed. The mode of occupation and use of the land, unemployment, under-nutrition, migration, etc., raise the question of the growing difficulties confronting the control of the disease, both in rural areas where populations are extremely mobile as well as in the poorly organized urban population. Epidemiological investigation is fulfithing its role in its attenpts to understand the complex relationships of an intrinsecally social nature of the health/disease process between health problems and the quality of life for the purpose of producing consistent disease control models.

A esquistossomose continua a ser um problema de saúde pública no Nordeste do Brasil embora o emprego, em larga escala, da quimioterapia venha sendo apontado como um dos fatores responsáveis pela redução das formas graves. O Estado de Pernambuco vem apresentando taxas crescentes de infecção humana para esquistossomose com perfil epidemiológico de prevalências crônicas (até 80%) na região rural e casos recentes de infecção aguda no litoral. Discute-se a reprodução e expansão da esquistossomose a partir de uma concepção estrutural e histórica de causas, onde se inserem fatores não só de ordem biológica mas também sociais, políticos e culturais que vêm contribuindo para a formação dos quadros endêmicos: a forma de ocupação e do uso da terra, desemprego, desnutrição, migração e outros. Questionam-se as crescentes dificuldades para o controle da doença e o papel da investigação epidemiológica na compreensão da essência social do processo saúde/doença.

Schistosomiasis mansoni can be considered an important public health problem in Northeastern Brazil, in spite of the reduction in the prevalence of the hepatosplenic clinical forms which have been attributed to the large scale use of chemotherapy in this country. However, the rise in the prevalence rates and the spread of this endemic disease to new areas show that schistosomiasis is assuming its must cruel expression: less lethal but more greatly incapacitating in terms of irreversible physical and moral damage to human beings. The state of Pernambuco presents growing rates for schistosomiasis infection in humans. The epidemiological profile of this disease displays high and consistent prevalence rates (up to 80%) in rural areas, and new cases of acute infection on the coast, where schistosomiasis has recently been introduced. The reproduction and expansion of this endemic disease can be better understood on the basic of a conception of structural and historical causation. The disease construction process should be reconstructed in the light of biological as well as the social, political and cultural factors which are jointly responsible for the present endemic situation. Within that frame work, the historical and socio-economic features that interact with the parasite and give rise to the present proportions of the schistosomiasis epidemic in Pernambuco are discussed. The mode of occupation and use of the land, unemployment, under-nutrition, migration, etc., raise the question of the growing difficulties confronting the control of the disease, both in rural areas where populations are extremely mobile as well as in the poorly organized urban population. Epidemiological investigation is fulfithing its role in its attenpts to understand the complex relationships of an intrinsecally social nature of the health/disease process between health problems and the quality of life for the purpose of producing consistent disease control models.

The subject of this conference reflects the scientific community's interest in seeking to understand the complex causal web whose various social, economic, and biological components interact in the production and reproduction of schistosomiasis and its control in relation to community participation. From the onset, the author stresses the impossibility of dealing separately with community participation, as if social components were just one more "weapon" in the arsenal for schistosomiasis control. This study begins with a brief historical review of the 71 years of control activities with this endemic disease, stressing the enormous efforts and huge expenditures in this field vis-à-vis the limited results, despite the extraordinary technological development of specific, classical control inputs such as new treatment drugs and molluscicides. The article then discusses the various strategies used in control programs, emphasizing ideological consistencies and contradictions. Interactions at the macro and micro levels are discussed, as are the determinants and risk factors involved in producing the disease's endemicity. Unequal occupation of space leaves the segregated portion of the population exposed to extremely favorable conditions for transmission of the disease. This raises the issue of how to control an endemic disease which is so closely linked to the way of life imposed on the population. The study challenges the classical control model and suggests an alternative model now undergoing medium-term investigation in the States of Espirito Santo, and Pernambuco, Brazil. The author concludes that we do not need new strategies, but a new control model, contrary to the prevailing classical model in both concept and practice. From the conceptual point of view, the new model mentioned above is different from others in that schistosomiasis control is seen from a social perspective stressing the population's accumulated knowledge in addition to the building of shared knowledge. The model's praxis has the following characteristics: (1) it is integrated with and financed by research agencies and health services; (2) it operates at the local health services level; (3) use of molluscicides has been eliminated; (4) emphasis is given to individual medical treatment and improvement of sanitary conditions.