OBJECTIVE:Investigate breeding sites with host snails and autochthonous human cases of schistosomiasis. METHODS:Between July 2010 and September 2012 were performed: (1) malacological survey searching for breeding sites, collection and identifi cation of Biomphalaria snails positive for Schistosoma mansoni in Recife, PE, Northeastern Brazil; (2) prevalence survey in 2,718 schoolchildren aged from seven to 14 years old to identify cases of schistosomiasis, clinical examination and ultrasound in positive cases of S. mansoni. The autochthony of the cases was investigated and the case were clinically evaluated. The cases and breeding sites were georeferenced and spatially described. RESULTS:The results identifi ed 30 breeding with B. straminea, four of which were potential foci of transmission, as molecular testing identifi ed snails with S. mansoni DNA. There were 14 children diagnosed with schistosomiasis, of which fi ve were considered to be autochthonous cases of the disease. CONCLUSIONS:Urgent measures are required in order to avoid schistosomiasis becoming endemic to Recife, as has happened in other coastal areas of the state of Pernambuco.

Abstract. In 2012 a malacological survey of the breeding sites of Biomphalaria glabrata and B. straminea, the two intermediate host snails of Schistosoma mansoni, was carried out on Itamaraca Island in Pernambuco, Brazil. This study has now been extended by studying the competition between the two species. Snails were collected and dissected to identify the species and tests were performed to verify S. mansoni infection. Student's t test was used to compare the proportion between the two species and their breeding sites and a parasitological survey was conducted among local residents, using the Kato-Katz method. The spatial distribution of the two snail species was determined using TerraView, while a snail density map was constructed by Kernel estimate. The survey identified two breeding sites for B. glabrata with 17 specimens and 19 breeding sites for B. straminea with 459 snails, all of them negative for S. mansoni infection. The statistical analysis revealed that the proportion of the numbers of specimens and breeding sites of B. straminea (37.84 ± 9.01) were significantly greater than those of B. glabrata (8.50 ± 6.50). Parasitological examinations from 41 residents diagnosed two cases of schistosomiasis with parasite loads of 60 and 84 eggs per 1 g of stool, respectively. This indiction of a competitive process between the two snail species requires monitoring of schistosomiasis in the resident and travelling human populations occupying this environment, which could potentially result in social and economic changes on the island risking its attraction as a centre for eco-tourism.

Realizou-se um inquérito malacológico em criadouros, permanentes e temporários, no bairro de Piedade, Jaboatão dos Guararapes, Pernambuco, entre novembro de 2006 e novembro de 2007 com o objetivo de conhecer a fauna malacológica dessa localidade, bem como o potencial de transmissão da esquistossomose mansoni. Além de Biomphalaria glabrata (Say, 1818), foram coletados moluscos Drepanotrema cimex (Moricand, 1837), Pomacea sp e Melanoides tuberculatus (Muller, 1774). Do total de Biomphalaria glabrata coletado, 1.490 exemplares encontraram-se vivos, sendo que 74 (5%) estavam positivos para Schistosoma mansoni. O maior número de moluscos capturados e todos aqueles positivos para Schistosoma mansoni foram coletados na estação anual das chuvas. Foi observada também a presença de outras larvas de trematódeos infectando os moluscos Biomphalaria glabrata. Pertencentes às famílias Strigeidae e Diplostomatidae, apresentam, a primeira vista, morfologia que pode levar a confusão com as cercárias do Schistosoma mansoni, tornando-se indispensável seu conhecimento para o diagnóstico diferencial do agente causador da esquistossomose.

ABSTRACT. Ecological aspects and malacological survey to identification of transmission riskglabrata collected, 44 specimens were positive for Schistosoma mansoni Sambon, 1907 cercariae and 91 specimens were positive for other trematode larvae. One Pomacea sp. specimen was positive for trematode larvae. These data, spatially georeferenced, will be used for determination of risk' sites for schistosomiasis transmission at Carne de Vaca beach and furthermore, they will be used for computational simulations to determine the expansion process of schistosomiasis in state of Pernambuco.

INTRODUCTION: The prevalence and intensity of geohelminth infections and schistosomiasis remain high in the rural areas of Zona da Mata, Pernambuco (ZMP), Brazil, where these parasites still represent a significant public health problem. The present study aimed to spatially assess the occurrences of schistosomiasis and geohelminthiasis in the ZMP. METHODS: The ZMP has a population of 1,132,544 inhabitants, formed by 43 municipalities. An ecological study was conducted, using secondary data relating to positive human cases and parasite loads of schistosomiasis and positive human cases of geohelminthiasis that were worked up in Excel 2007. We used the coordinates of the municipal headquarters to represent the cities which served as the unit of analysis of this study. The Kernel estimator was used to spatially analyze the data and identify distribution patterns and case densities, with analysis done in ArcGIS software. RESULTS: Spatial analysis from the Kernel intensity estimator made it possible to construct density maps showing that the northern ZMP was the region with the greatest number of children infected with parasites and the populations most intensely infected by Schistosoma mansoni. In relation to geohelminths, there was higher spatial distribution of cases of Ascaris lumbricoides and Trichuris trichiura in the southern ZMP, and greater occurrence of hookworms in the northern/central ZMP. CONCLUSIONS: Despite several surveys and studies showing occurrences of schistosomiasis and geohelminthiasis in the ZMP, no preventive measures that are known to have been effective in decreasing these health hazards have yet been implemented in the endemic area.

A expansão da esquistossomose para o litoral de Pernambuco vem sendo registrada desde 1992 com a detecção de casos agudos da doença em indivíduos de classe média/alta. Para diagnosticar este novo cenário de transmissão da endemia em localidades turísticas na orla marítima do estado é de fundamental importância o conhecimento prévio da distribuição georreferenciada das espécies de moluscos vetores, por meio de mapas que apontem sua exata localização, assim como é necessário espacializar as situações de risco biológico e as condições ambientais insalubres. Nos períodos de 15 a 18 de setembro de 2008 e 10 a 13 de setembro de 2013 foram realizadas caravanas expedicionárias, por epidemiologistas e parasitologistas por 11 municípios do litoral do estado, percorrendo todas as coleções de água doce distantes até 2 km da beira-mar. Os dados foram georreferenciados para posterior condução de análises espaciais. Para identificação da positividade dos exemplares de Biomphalaria glabrata, foi utilizada a técnica de exposição à luz. Os espécimes de B. straminea que permaneceram negativos até o 15º dia foram submetidos à técnica de diagnóstico molecular (PCR-single tube). Nas coletas de 2008 foram capturados 3.392 caramujos B. glabrata e 725 B. straminea, cujas taxas de infecção variaram entre 0,9% a 22,2%. Em 2013, foram coletados 948 B. glabrata e 504 B. straminea e somente foram encontrados caramujos eliminando cercarias na localidade Porto de Galinhas com taxa de infectividade de 81,4%, permanecendo como localidade de maior risco para transmissão da esquistossomose.

OBJECTIVE Diagnose risk environments for schistosomiasis in coastal localities of Pernambuco using geoprocessing techniques.METHODS A coproscopic and malacological survey were carried out in the Forte Orange and Serrambi areas. Environmental variables (temperature, salinity, pH, total dissolved solids and water fecal coliform dosage) were collected from Biomphalaria breeding sites or foci. The spatial analysis was performed using ArcGis 10.1 software, applying the kernel estimator, elevation map, and distance map.RESULTS In Forte Orange, 4.3% of the population had S. mansoni and were found two B. glabrata and 26 B. straminea breeding sites. The breeding sites had temperatures of 25ºC to 41ºC, pH of 6.9 to 11.1, total dissolved solids between 148 and 661, and salinity of 1,000 d. In Serrambi, 4.4% of the population had S. mansoni and were found seven B. straminea and seven B. glabrata breeding sites. Breeding sites had temperatures of 24ºC to 36ºC, pH of 7.1 to 9.8, total dissolved solids between 116 and 855, and salinity of 1,000 d. The kernel estimator shows the clusters of positive patients and foci of Biomphalaria, and the digital elevation map indicates areas of rainwater concentration. The distance map shows the proximity of the snail foci with schools and health facilities.CONCLUSIONS Geoprocessing techniques prove to be a competent tool for locating and scaling the risk areas for schistosomiasis, and can subsidize the health services control actions.

We developed a stochastic model for quantitative risk assessment for the Schistosoma mansoni (SM) parasite, which causes an endemic disease of public concern. The model provides answers in a useful format for public health decisions, uses data and expert opinion, and can be applied to any landscape where the snail Biomphalaria glabrata is the main intermediate host (South and Central America, the Caribbean, and Africa). It incorporates several realistic and case-specific features: stage-structured parasite populations, periodic praziquantel (PZQ) drug treatment for humans, density dependence, extreme events (prolonged rainfall), site-specific sanitation quality, environmental stochasticity, monthly rainfall variation, uncertainty in parameters, and spatial dynamics. We parameterize the model through a real-world application in the district of Porto de Galinhas (PG), one of the main touristic destinations in Brazil, where previous studies identified four parasite populations within the metapopulation. The results provide a good approximation of the dynamics of the system and are in agreement with our field observations, i.e., the lack of basic infrastructure (sanitation level and health programs) makes PG a suitable habitat for the persistence and growth of a parasite metapopulation. We quantify the risk of SM metapopulation explosion and quasi-extinction and the time to metapopulation explosion and quasi-extinction. We evaluate the sensitivity of the results under varying scenarios of future periodic PZQ treatment (based on the Brazilian Ministry of Health's plan) and sanitation quality. We conclude that the plan might be useful to slow SM metapopulation growth but not to control it. Additional investments in better sanitation are necessary.