Malacological, socio-environmental evaluation, and evidence of local transmission and maintenance of schistosomiasis in an urban area of Northeast Brazil

To present the current epidemiological scenario of schistosomiasis related to urban transmission through an epidemiological risk assessment in Porto de Galinhas, a coastal area of Pernambuco, Brazil. Malacological and parasitological surveys were performed between the years 2018 and 2020. Snails were identified taxonomically and examined to confirm infection by Schistosoma mansoni, and so to identify Schistosomiasis Transmission Foci (STF) by the artificial light exposure technique. Stool samples were examined using the Kato-Katz method to identify schistosomiasis cases. Socioeconomic, environmental, behavioural and health data were collected by a questionnaire applied to participates in the survey and used to predict the schistosomiasis risk occurrence by multivariate logistic regression. In all, a total of 6466 snails of Biomphalaria glabrata were collected and 36 breeding sites were identified, of which 25 % were STF. A total of 2236 individuals took part of the survey which identified 187 cases of schistosomiasis, registering a positivity percentage of 8.36 %. The surveys identified the neighbourhoods with the highest risk for transmission while the socioenvironmental analysis identifies other risk factors for disease occurrence, such as gender, age range, level of education and absence of water drainage. We found that areas with poor sanitation, flooding during winter periods and dwellings located near mangroves should be treated by health authorities as priority areas for health interventions to minimize disease transmission. In addition, efforts to improve the population's educational level could certainly contribute to the adoption of measures to prevent and control this neglected tropical disease.

FioSchisto's expert perspective on implementing WHO guidelines for schistosomiasis control and transmission elimination in Brazil

The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission. The perspectives presented here, collectively prepared by members of the Oswaldo Cruz Foundation's (Fiocruz) Schistosomiasis Translational Program (FioSchisto), along with invited experts, examine the feasibility of the WHO recommendations for the Brazilian settings, providing appropriate recommendations for public health policies applicable to the epidemiological reality of Brazil, and suggests future research to address relevant issues. In Brazil, the provision of safe water and sanitation should be the key action to achieve schistosomiasis elimination goals. The agencies involved in measures implementation should act together with the Primary Care teams for planning, executing, monitoring, and evaluating actions in priority municipalities based on their epidemiological indicators. Host snails control should prioritize judicious ecological interventions at breeding sites. The Information, Education, and Communication (IEC) strategy should be associated with water and sanitation and other control actions, actively involving school community. To identify infected carriers, FioSchisto recommends a two-stage approach of immunological and molecular tests to verify transmission interruption during the intervention and beyond. Praziquantel administration should be done under medical supervision at the Primary Care level. MDA should be considered in exceptional settings, as a measure of initial attack strategy in locations presenting high endemicity, always integrated with water and sanitation, IEC, and snail control. To assist decision-making, as well as the monitoring and evaluation of strategic actions, there is a need for an Information System. FioSchisto considers this systematization essential to make investments in strategic research to support the improvement of schistosomiasis control actions. Efforts toward schistosomiasis elimination in Brazil will succeed with a paradigm shift from the vertical prescriptive framework to a community-centered approach involving intersectoral and interdisciplinary collaboration.

Factors associated with severe forms and deaths from schistosomiasis and application of probabilistic linkage in databases, state of Pernambuco, Brazil, 2007-2017

OBJECTIVE

To verify the agreement of data on severe forms and deaths from schistosomiasis recorded in the Brazilian Notifiable Diseases Information System and the Mortality Information System, sociodemographic variables with the occurrence of severe forms and deaths, and the temporal trend of the disease in the state of Pernambuco, Brazil.

METHODS

This is an ecological, descriptive, time series study with data on severe forms and deaths from schistosomiasis in Pernambuco, from 2007 to 2017. For the linkage between databases, a function was developed in python programming language, using the Soundex method. To identify sociodemographic and health factors that correlated with the dependent variables, Pearson's correlation test was applied. For trend analysis, linear regression was applied.

RESULTS

We identified 9,085 severe cases, 1,956 deaths, and 186 cases in the linkage. The correlation between the average positivity rate with the general water supply and waste collection was 0.22 and 0.26 respectively. We verified a correlation of the average cumulative mortality rate with water supply by well or spring (r=0.27), water supply by the general network (r=0.3), waste collection (r=0.42), and road urbanization (r=0.29). We found 3,153 severe forms in 2007 with a decrease trend and 205 deaths in 2010, without a trend pattern.

CONCLUSION

There is a need for greater investments in disease control and in the quality of information, especially in the record of severe forms, considering that, due to the pathophysiology of the disease, death only occurs when the individual develops the chronic form, and its notification on the Notifiable Diseases Information System is imperative.

Factors associated with severe forms and deaths from schistosomiasis and application of probabilistic linkage in databases, state of Pernambuco, Brazil, 2007–2017

ABSTRACT Objective: To verify the agreement of data on severe forms and deaths from schistosomiasis recorded in the Brazilian Notifiable Diseases Information System and the Mortality Information System, sociodemographic variables with the occurrence of severe forms and deaths, and the temporal trend of the disease in the state of Pernambuco, Brazil. Methods: This is an ecological, descriptive, time series study with data on severe forms and deaths from schistosomiasis in Pernambuco, from 2007 to 2017. For the linkage between databases, a function was developed in python programming language, using the Soundex method. To identify sociodemographic and health factors that correlated with the dependent variables, Pearson’s correlation test was applied. For trend analysis, linear regression was applied. Results: We identified 9,085 severe cases, 1,956 deaths, and 186 cases in the linkage. The correlation between the average positivity rate with the general water supply and waste collection was 0.22 and 0.26 respectively. We verified a correlation of the average cumulative mortality rate with water supply by well or spring (r=0.27), water supply by the general network (r=0.3), waste collection (r=0.42), and road urbanization (r=0.29). We found 3,153 severe forms in 2007 with a decrease trend and 205 deaths in 2010, without a trend pattern. Conclusion: There is a need for greater investments in disease control and in the quality of information, especially in the record of severe forms, considering that, due to the pathophysiology of the disease, death only occurs when the individual develops the chronic form, and its notification on the Notifiable Diseases Information System is imperative.

Urban schistosomiasis: An ecological study describing a new challenge to the control of this neglected tropical disease

Background

Social and environmental vulnerabilities contribute to the persistence and increase of Schistosomiasis, which has been a public health problem in Brazil and worldwide. In this study, we aimed to monitor the entry, installation, and maintenance of schistosomiasis transmission in an urban area on the Brazilian coast over two decades (2000-2010/2010-2020).

Methods

This population-based cross-sectional study was conducted in Porto de Galinhas, state of Pernambuco, Brazil, to investigate the dynamics of schistosomiasis transmission in the urban area. Through 3 malacological and parasitological surveys and using geoprocessing technologies, schistosomiasis transmission foci (STF), as well as cases of the disease were identified and quantified. Statistical and geoprocessing tools were used to analyse the data.

Findings

Overall, the number of STF decreased from 15 (2000) to 11 (2010) and then to 9 (2020). Although the infection ratio of snails in 2000 has decreased from 16·1% to 5·8% in 2010, we observed an increase to 7·2% in 2020. Additionally, 6,499 individuals were analysed (2012 in 2000; 2459 in 2010, and 2028 in 2020) and the prevalence of human infection has decreased over years, from 32·5% (2000), 16·6% (2010) to 8·8% (2020). The disorderly urbanization process was directly related to the spatial distribution of STF and schistosomiasis cases, causing a new scenario where people became infected by walking on unpaved and flooded streets.

Interpretation

Although we observed a decreasing in schistosomiasis cases and STF, this NTD became a health problem related to urbanization in the study area. The challenge to overcome this new sort of transmission will require a greater understanding of the disorderly migration, spatial occupation, and degradation of the environment.

Funding

National Council for Scientific and Technological Development (CNPq), Ministry of Science, Technology, Innovations and Communications, Brazil.

Mapping the risk for transmission of urban schistosomiasis in the Brazilian Northeast

This is an analysis of the risk of schistosomiasis transmission in the city of Recife in the Northeast of Brazil based on the number of schistosomiasis cases (Schistosoma mansoni) registered for the period 2007-2017 together with data resulting from active search of breeding sites of the Biomphalaria snail intermediate host. The analyses were performed using Kernel Density Estimation (KDE), SaTScan and Map Algebra methodology using human socio-demographic data and biotic and abiotic data from the snail breeding sites. Investigating 44 breeding sites resulted in a total of 3.800 snails, 31.8% of which were positive for S. mansoni DNA. These data were considered in relation to total of 652 schistosomiasis cases. The KDE showed two high-risk and two medium-risk clusters, while three significant clusters were identified by SaTScan. Combining these data with the Map Algebra methodology showed that all high-risk neighbourhoods had breeding sites with snails positive for S. mansoni. It was concluded that schistosomiasis transmission cannot be controlled without basic sanitation and sewage management in the presence of Biomphalaria snails. The technique of Map Algebra was found to be fundamental for the analysis and demonstration of areas with a high probability of schistosomiasis transmission.

Gas chromatography-mass spectrometry (GC/MS) reveals urine metabolites associated to light and heavy infections by Schistosoma mansoni in mice

High-throughput profiling of metabolites has been used to identify metabolic changes in murine models as a response to the infection by the parasitic trematode Schistosoma. These investigations have contributed to our understanding on the pathogenesis of this tropical neglected disease, with a potential of helping diagnosis. Here, our study aimed to investigate the application of gas chromatography-mass spectrometry (GC/MS) on the profiling of urine metabolites from mice carrying infections by Schistosoma mansoni. Two larval infection doses created distinctive infection intensities in mice, whereby the heavily infected animals were found to release 25 times more eggs in faeces than lightly infected animals. Over 200 urine metabolites were identified from these animals by GC/MS, following two complementary derivatisation methods. A list of 14 individual metabolites with altered relative abundances between groups were identified. Most of the altered metabolites showed a trend of increased abundances in response to infection intensity, indicating host-specific metabolic alterations as a result of the disease. Hippurate, a metabolite which concentration is intimately modulated by the gut microbiota, was found to be highly correlated to infection intensity. Our study showed that urine metabolic profiling by GC/MS can distinguish non-infected animals from those carrying light and heavy infections by S. mansoni, revealing metabolites associated to the infection and providing insights on the pathogenesis of schistosomiasis.

Spinal neuroschistosomiasis caused by Schistoma mansoni: cases reported in two brothers

Background

Spinal neuroschistosomiasis (SN) is one of the most severe clinical presentations of schistosomiasis infection and an ectopic form of the disease caused by any species of Schistosoma. In Brazil, all cases of this clinical manifestation are related to Schistosoma mansoni, the only species present in the country. Although many cases have been reported in various endemic areas in Brazil, this is the first time in the literature that SN is described in two brothers.

Case presentation

Two cases of SN were accidentally diagnosed during an epidemiological survey in an urban area endemic for schistosomiasis transmission. Both patients complained of low back pain and muscle weakness in the lower limbs. Sphincter dysfunction and various degrees of paresthesia were also reported. The patients’ disease was classified as hepato-intestinal stage schistosomiasis mansoni at the onset of the chronic form. A positive parasitological stool test for S. mansoni, clinical evidence of myeloradicular damage and exclusion of other causes of damage were the basic criteria for diagnosis. After treatment with praziquantel and corticosteroid, the patients presented an improvement in symptoms, although some complaints persisted.

Conclusions

It is important to consider SN when patients come from areas endemic for transmission of schistosomiasis mansoni. Clinical physicians and neurologists should consider this diagnostic hypothesis, because recovery from neurological injuries is directly related to early treatment. As, described here in two brothers, a genetic predisposition may be related to neurological involvement. Primary care physicians should thus try to evaluate family members and close relatives in order to arrive at prompt schistosomiasis diagnosis in asymptomatic individuals and propose treatment in an attempt to avoid progression to SN.

Spatial risk analysis on occurrences and dispersal of Biomphalaria straminea in and endemic area for schistosomiasis

Background & objectives

: Schistosomiasis is a rural endemic disease that has been expanding to urban and coastal areas in the state of Pernambuco, Brazil. The aim of this study was to characterize the distribution of breeding sites of the causative vector, Biomphalaria straminea in an endemic municipality for schistosomiasis and to present the predictive models for occurrences and dispersal of this vector snail to new areas.

Methods

: A malacological survey was conducted during January to December 2015 in the municipality of São Lourenço da Mata, Pernambuco, Brazil to identify the breeding sites of Biomphalaria. Faecal contamination was determined by means of the Colitag™ diagnostic kit. Rainfall data were collected, and correlated with snail distribution data. Kernel density estimation, kriging and maximum entropy (MaxEnt) modeling were used for spatial data analysis, by means of the spatial analysis software packages.

Results

: Out of the 130 demarcated collection points, 64 were classified as breeding sites for B. straminea. A total of 5,250 snails were collected from these sites. Among these 64 sites, four were considered as foci of schistosomiasis transmission and 54 as potential transmission foci. An inverse relationship between rainfall and snail density was observed. Kernel spatial analysis identified three areas at higher risk of snail occurrence, which were also the areas of highest faecal contamination and included two transmission foci. Kriging and MaxEnt modeling simulated the scenarios obtained through the kernel analyses.

Interpretation & conclusion

: Use of geostatistical tools (Kriging and MaxEnt) is efficient for identifying areas at risk and for estimating the dispersal of Biomphalaria species across the study area. Occurrence of B. straminea in the study area is influenced by the rainy season, as it becomes more abundant during the period immediately after the rainy season, increasing the risk of dispersal and the appearance of new transmission foci.

Investigation of schistosomiasis cases and deaths in the city of Recife, Pernambuco, Brazil, 2005-2013

OBJECTIVE

to describe schistosomiasis cases and deaths among residents of the city of Recife, Pernambuco, Brazil, from 2005 to 2013.

METHODS

this was a descriptive epidemiological study using data from the Mortality Information System (SIM) (2005-2013) and the Notifiable Diseases Information System (SINAN) (2007-2013); active tracing of the relatives of the dead was undertaken and probabilistic linkage of the databases (2007-2013) was performed using the Reclink program.

RESULTS

297 schistosomiasis deaths were recorded on the SIM system; through active tracing, 130 relatives were contacted and 20.8% autochthony was identified; 388 cases resident in Recife were registered on the SINAN system; through probabilistic linkage, 23 matching records were identified on SIM and SINAN.

CONCLUSION

investigation of deaths showed that some individuals had never traveled outside Recife and progressed to the chronic stage of the disease; 23.8% of the cases registered on SINAN had Recife as the municipality in which infection occurred.

A field survey using LAMP assay for detection of Schistosoma mansoni in a low-transmission area of schistosomiasis in Umbuzeiro, Brazil: Assessment in human and snail samples

Background

In Brazil, schistosomiasis is a parasitic disease of public health relevance, mainly in poor areas where Schistosoma mansoni is the only human species encountered and Biomphalaria straminea is one of the intermediate host snails. A nested-PCR based on a specific mitochondrial S. mansoni minisatellite DNA region has been successfully developed and applied as a reference method in Brazil for S. mansoni detection, mainly in host snails for epidemiological studies. The amplification efficiency of LAMP is known to be higher than PCR. The present work aimed to assess the utility of our previously described SmMIT-LAMP assay for S. mansoni detection in human stool and snail samples in a low-transmission area of schistosomiasis in the municipality of Umbuzeiro, Paraíba State, Northeast Region of Brazil.

Methodology/Principal findings

A total of 427 human stool samples were collected during June-July 2016 in the municipality of Umbuzeiro and an overall prevalence of 3.04% (13/427) resulted positive by duplicate Kato-Katz thick smear. A total of 1,175 snails identified as Biomphalaria straminea were collected from 14 breeding sites along the Paraíba riverbank and distributed in 46 pools. DNA from human stool samples and pooled snails was extracted using the phenol/chloroform method. When performing the SmMIT-LAMP assay a total of 49/162 (30.24%) stool samples resulted positive, including 12/13 (92.31%) that were Kato-Katz positive and 37/149 (24.83%) previously Kato-Katz negative. By nested-PCR, only 1/46 pooled DNA snail samples was positive. By SmMIT-LAMP assay, the same sample also resulted positive and an additional one was positive from a different breeding site. Data of human and snail surveys were used to build risk maps of schistosomiasis incidence using kernel density analysis.

Conclusions/Significance

This is the first study in which a LAMP assay was evaluated in both human stool and snail samples from a low-transmission schistosomiasis-endemic area. Our SmMIT-LAMP proved to be much more efficient in detection of S. mansoni in comparison to the 'gold standard' Kato-Katz method in human stool samples and the reference molecular nested-PCR in snails. The SmMIT-LAMP has demonstrated to be a useful molecular tool to identify potential foci of transmission in order to build risk maps of schistosomiasis.

In Brazil, around 1.8 million people, mostly in the northeastern region of the country, are thought to be infected with Schistosoma mansoni. Snails of the genus Biomphalaria serve as intermediate hosts of the S. mansoni. A special program for schistosomiasis control was implemented more than 40 years ago in Brazil, decreasing prevalence, morbidity, and mortality over the past years. PCR-based diagnostic methods have been successfully applied in a few endemic areas of schistosomiasis in Brazil, although they are not still widely used due to the highly technical requirements making them unviable for routine application in field conditions. Loop-mediated isothermal amplification (LAMP) technology could be a powerful tool to apply for point-of-care testing in resource-poor settings. In previous work, a LAMP-based method to detect S. mansoni DNA, called SmMIT-LAMP, was developed by our research group to detect S. mansoni DNA testing stool samples from experimentally infected mice. Here, with the aim to apply SmMIT-LAMP as a cost-effective molecular tool for the detection of S. mansoni in field applicable conditions, we assess SmMIT-LAMP in human and snail samples collected in an endemic area of Brazil. The results obtained by Kato-Katz analysis of human stool samples and nested-PCR performed in snails were compared with the SmMIT-LAMP assay. It is the first time that a LAMP-based method has been used to identify potential transmission foci and to evaluate the epidemiological risk of acquiring schistosomiasis.

Urban transmission of schistosomiasis: new epidemiological situation in the forest area of Pernambuco

Introduction:

Schistosomiasis is considered an endemic disease in Vitória de Santo Antão, Pernambuco, a district which has presented both high incidence and prevalence of it for decades. Poor environmental conditions lead to contamination of water sources in rural areas, which are used by the population during daily activities, resulting in typical transmission. Recently, there has been evidence of vector snails in urban areas, which could set a new model for schistosomiasis transmission in this district.

Objective:

To identify the new epidemiological situation for the urban transmission of schistosomiasis in Vitória de Santo Antão, Pernambuco.

Methods:

A malacological survey was conducted in all water sources in the city limits to investigate schistosomiasis vector snails (Biomphalaria spp.). The collected snails were examined for taxonomic identification and Schistosoma mansoni infection. All breeding sites were georeferenced to build risk maps through the TrackMaker PRO program and ArcGIS software.

Results:

We identified 22 Biomphalaria straminea breeding sites and collected 1,704 snails. One of these breeding sites was identified as a source of transmission and seven as potential sources of transmission. The designed maps identified two risk areas of urban transmission of schistosomiasis and expansion areas for breeding sites, establishing an increased risk of transmission to the population.

Conclusion:

This study verified the existence of a new epidemiological situation in which the possibility of the urban transmission of the disease was confirmed.

The Geographic Information System applied to study schistosomiasis in Pernambuco

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.

Spatial analysis of viral hepatitis and schistosomiasis coinfection in an endemic area in Northeastern Brazil

INTRODUCTION:

This cross-sectional study analyzed the spatial distribution of hepatitis B or C virus (HBV/HBC) and schistosomiasis coinfection.

METHODS:

Serum samples were collected from patients with Schistosoma mansoni infection. These were tested for serological markers of HBV/HCV infection. The spatial distribution of coinfection was analyzed using intensity kernel estimation.

RESULTS:

Overall, 9.4% of individuals had contact with HBV and 1.7% of samples tested positive for anti-HCV antibodies. We identified clusters of risk located in the central region.

CONCLUSIONS:

Spatial analysis allowed visualization of high-risk areas, leading to a definition of priority areas to be targeted for intensification of control interventions.

Ovarian Manson's Schistosomiasis: Rare Diagnosis or Underestimated Prevalence?

The occurrence of Manson's schistosomiasis in organs of the female reproductive tract is an uncommon event, given that the etiological agent for this disease is a blood parasite that inhabits the mesenteric veins. In this case report, a 45-year-old female patient reported that her first symptoms had been strong pain in the left iliac region around two years earlier. An endovaginal pelvic ultrasonography showed that the left ovary was enlarged, and the report suggested that this finding might be correlated with clinical data and tumor markers. After being examined at several healthcare services, the patient was referred to an oncology service due to suspected neoplasia, where she underwent a left ovariectomy. The result from the histopathological examination showed the presence of granulomatous inflammatory processes surrounding both viable and calcified eggs of Schistosoma mansoni. There was no evidence of any neoplastic tissue. The patient was medicated and followed-up as an outpatient.

Morbidity of mansoni schistosomiasis in Pernambuco-Brazil: Analysis on the temporal evolution of deaths, hospital admissions and severe clinical forms (1999-2014)

BACKGROUND

Current scientific information reported that due to successive treatments of schistosomiasis cases in endemic areas of Brazil in the last 30 years, there has been a decrease in severe clinical form (hepatosplenic) and mortality from upper gastrointestinal bleeding due to this disease. Against this information, literature data show that the state of Pernambuco presents significant percentage of deaths and hospitalizations due to schistosomiasis, and occurrence of severe clinical forms as schistosomiasis myeloradiculopathy and persistence of localities with high parasite loads. This scenario justified this research which seeking to update the morbidity and mortality of schistosomiasis in Pernambuco.

OBJECTIVE

To conduct a temporal analysis on the evolution of deaths, hospital admissions and severe forms of Manson's schistosomiasis over the last 16 years in Pernambuco, Brazil.

METHODS

It was performed a gathering secondary data on schistosomiasis, from healthcare information systems and from the records of Hospital das Clínicas, Federal University of Pernambuco (HC-UFPE), covering the period from 1999 to 2014.

RESULTS

From 1999 to 2013 were registred 2578 deaths due to schistosomiasis and between 2008 and 2014 were recorded 473 hospitalizations for this disease. Among 1999-2014 were identified 1943 cases of schistosomiasis treated at the Hospital das Clínicas of Pernambuco. Among these cases, 72.6% (n. 1411) of the individuals presented the hepatosplenic clinical form (HE), 60.8% (n. 858) were at the age group 30-59 years (adults) and 58% were female. Among the HE cases, 4.6% (n. 58) had ascites, 43.2% (n. 556) had upper gastrointestinal bleeding and 39.1% (n. 489) had collateral circulation. The pattern of fibrosis in the liver E/EC (advanced fibrosis) and F/FC (very advanced fibrosis) occurred in 65.5% (n. 793) of cases. Between 1999-2014 the evolution curve of severe clinical forms of schistosomiasis remained stable, showing a tendency to decline from 2012.

CONCLUSION

When compared to other states of Brazil, Pernambuco shows high numbers of deaths and hospital admissions due to schistosomiasis. The actions of the Schistosomiasis Control Program (PCE) have been developed in a disintegrated, disjointed and discontinuous way, which may explain the magnitude of deaths, hospitalizations and severe forms of the disease in Pernambuco, showing a lack of control and the maintenance of severe frame morbidity of schistosomiasis in this state.

Modelling of the distribution of Biomphalaria glabrata and Biomphalaria straminea in the metropolitan region of Recife, Pernambuco, Brazil

The occurrence of schistosomiasis is directly linked to the presence of its snail intermediate host Biomphalaria spp. Knowledge of geographical distribution, habitats and behaviour of these snails in relation to the climate is essential for guiding measures for disease prevention and control. This study aims to model the distribution of B. glabrata and B. straminea in schistosomiasis non-endemic areas of the metropolitan region of Recife (MRR) based on environmental data and estimates of snail distributions in endemic and neighbouring areas. We applied Kriging with the aim of determining the spatial distribution of these two snail species and MaxEnt for modelling their ecological behaviour. Kriging showed that the North and the Centre of the MRR were generally either snail-free or contained only B. straminea, while both snail species could be found in the South. MaxEnt supported our observation that the northern and southern coastal regions were favoured by B. glabrata and diurnal mean temperature variation; July rainfall and November rainfall were the three variables favouring Biomphalaria breeding sites that contributed the most in the predictive model we developed. The study showed the location of areas suitable to Biomphalaria spp. and therefore at potential risk, first for invasion of these snails and later for the development of new schistosomiasis- endemic areas. This information should be useful, not only to estimate expansion possibilities of this disease in the MRR, but also to point out the climatic variables that would contribute to this expansion, thereby allowing timely application of prevention and control measures.

Evaluation of serum levels of IL-9 and IL-17 in human Schistosoma mansoni infection and their relationship with periportal fibrosis

Serum levels of IL-9 and IL-17 cytokines were evaluated in patients in the acute, chronic phases and clinical forms of human schistosomiasis and in different classifications of periportal fibrosis. No significant differences between the groups of the disease with serum levels of cytokine were found. However, this study discusses the results of some cytokines that have not fully defined roles in the pathology of human schistosomiasis. Furthermore, an examination was made of subjects in the acute phase. This is an important group that is difficult to identify in areas where the disease is endemic. More studies are being undertaken to study the role of IL-9 and IL-17 in human Schistosoma mansoni infection and their relationship with the immunopathogenesis of disease.

FIRST RECORD OF PROSTATIC SCHISTOSOMIASIS IN PERNAMBUCO, BRAZIL: SIGNS OF CHRONICITY IN AN ENDEMIC DISEASE

A esquistossomose acomete, há séculos, a população rural de Pernambuco. Manifestações hepatoesplênicas e neurológicas desta parasitose têm sido frequentemente descritas. No entanto, a esquistossomose da próstata, causada pelo Schistosoma mansoni, nunca havia sido reportada em Pernambuco, o que demonstra a necessidade de registrar este caso. Apresentação do caso: Um paciente de 51 anos, após realizar uma prostectomia parcial por suspeita de neoplasia, foi diagnosticado com esquistossomose da próstata. Após o procedimento cirúrgico, foram coletadas amostras de fezes para a realização de testes parasitológicos que se revelaram positivos para S. mansoni, confirmando que o paciente ainda estava infectado. Exames laboratoriais e clínicos mostraram alterações na função hepática e confirmaram danos hepatointestinais. O acompanhamento ambulatorial do paciente demonstrou que os níveis de antígeno prostático específico permaneceram elevados e, um ano após a primeira intervenção cirúrgica, um exame anatomopatológico mostrou a permanência de lesões fibromatosas esquistossomóticas. Vale ressaltar que, após três tratamentos com praziquantel (abril e julho/2014, fevereiro/2015), os exames de fezes apresentaram-se negativos para S. mansoni. Conclui-se que este diagnóstico acidental de esquistossomose da próstata levanta dúvidas sobre a capacidade dos serviços de saúde para identificar e tratar as formas ectópicas da esquistossomose. A manutenção dos elevados níveis de PSA, mesmo após tratamento cirúrgico e farmacológico, sugerem que os danos causados por S. mansoni aos tecidos são irreversíveis. Portanto, os serviços de saúde devem estar preparados para investigar e diagnosticar os casos, visando à prevenção de sequelas crônicas e ao tratamento precoce.

First report of schistosomiasis on Serrambi beach, Ipojuca, State of Pernambuco

INTRODUCTION

The expansion of schistosomiasis to previously unaffected areas is being monitored by identifying new cases and georeferencing outbreaks of vector snails.

METHODS

In 2014, the Laboratório de Esquistossomose began an epidemiological survey in Serrambi and registered 2,574 people living there.

RESULTS

Of these subjects, 1,414 (54.9%) underwent feces examination and 63 (4.5%) were diagnosed with Schistosoma mansoni infection. At this locality, seven breeding sites each were identified for Biomphalaria straminea and Biomphalaria glabrata. At two sites, B. glabrata were shedding cercariae.

CONCLUSIONS

Implementing preventive measures is necessary to avoid the establishment of schistosomiasis in yet another tourist locality, Pernambuco.

Using mobile technology to conduct epidemiological investigations

INTRODUCTION

The aim of this study was to report the experience of an epidemiological field survey for which data were collected and analyzed using tablets.

METHODS

The devices used Epi Info 7 (Android version), which has been modeled a database with variables of the traditional form.

RESULTS

Twenty-one households were randomly selected in the study area; 75 residents were registered and completed household interviews with socioeconomic and environmental risk variables.

CONCLUSIONS

This new technology is a valuable tool for collecting and analyzing data from the field, with advantageous benefits to epidemiological surveys.

Risk analysis for occurrences of schistosomiasis in the coastal area of Porto de Galinhas, Pernambuco, Brazil

Background

Manson’s schistosomiasis continues to be a severe public health problem in Brazil, where thousands of people live under the risk of contracting this parasitosis. In the Northeast of Brazil, schistosomiasis has expanded from rural areas to the coast of Pernambuco State, where the intermediate host is Biomphalaria glabrata snails. This study aims at presenting situational analyses on schistosomiasis at the coastal locality of Porto de Galinhas, Pernambuco, Brazil, by determining the risk factors relating to its occurrence from the epidemiological and spatial perspectives.

Methods

In order to gather prevalence data, a parasitological census surveys were conducted in 2010 in the light of the Kato-Katz technique. Furthermore, malacological surveys were also conducted in the same years so as to define the density and infection rates of the intermediate host. Lastly, socioeconomic-behavioral survey was also conducted to determine the odds ratio for infection by Schistosoma mansoni. Based on these data, spatial analyses were done, resulting in maps of the risk of disease transmission. To predict the risk of schistosomiasis occurrence, a multivariate logistic regression was performed using R 2.13 software.

Results

Based on prevalence, malacological and socioeconomic-behavioural surveys, it was identified a prevalence of 15.7% in the investigated population (2,757 individuals). Due to the malacological survey, 36 breeding sites were identified, of which 11 were classified as foci of schistosomiasis transmission since they pointed out snails which were infected by Schistosoma mansoni. Overall, 11,012 snails (Biomphalaria glabrata) were collected. The multivariate regression model identified six explanatory variables of environmental, socioeconomic and demographic nature. Spatial sweep analysis by means of the Bernoulli method identified one statistically significant cluster in Salinas (RR = 2.2; p-value < 0.000), the district with the highest occurrence of cases.

Conclusions

Based on the resulting information from this study, the epidemiological dimensions of this disease are significant and severe, within the scenario of schistosomiasis in Pernambuco state. The risk factors which were identified in the predictive model made it clear that the environmental and social conditions influence on the schistosomiasis occurrences.

Spatial analysis of schistosomiasis human cases in the horticultural community of Zona da Mata of Pernambuco state, Brazil

The objective of this study was to describe the spatial distribution of schistosomiasis in horticultural community of Natuba, district of Vitória de Santo Antão, Pernambuco state. It was conducted a parasitological survey, examined the fecal material of 310 community residents. The cases positive for Schistosoma mansoni were geocoded and included in the computerized template of the community, generating maps of spatial distribution with kernel estimators. The results showed a high prevalence of schistosomiasis, with 28.4% of the parasites. Other parasites were found in 25.8% of the population. The use of GIS tools to map and understand the possible distribution of cases of schistosomiasis in the space occupied by the community highlighting and listing locations of lower elevation (able to flooding), with a higher frequency of human cases. Studies like this provide information to the local health services, may intervene and bring about change for individuals living in areas with low housing conditions to minimize their exposure to risk of contracting schistosomiasis.

Spatial distribution of schistosomiasis and geohelminthiasis cases in the rural areas of Pernambuco, Brazil

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.

Biological and environmental factors associated with risk of schistosomiasis mansoni transmission in Porto de Galinhas, Pernambuco State, Brazil

Schistosomiasis has expanded to the coast of Pernambuco State, Brazil, where there are frequent reports of Biomphalaria glabrata snails and human cases of the disease. This study analyzes factors related to schistosomiasis transmission risk in Porto de Galinhas. A one-year malacological survey was conducted to identify biological, abiotic, and environmental factors related to the host snail breeding sites. Data analysis used Excel 2010, GTM Pro, and ArcGis 10. A total of 11,012 B. glabrata snails were captured in 36 breeding sites, and 11 schistosomiasis transmission foci were identified. A negative correlation was found between breeding site temperature and snail density and infection rate, and a positive correlation with pH and salinity. The rainy season showed a positive correlation with snail density and infection rate. The study emphasizes the factors involved in the maintenance of schistosomiasis breeding sites, in light of persistence of this disease in Porto de Galinhas for more than 10 years.

Schistosomiasis transmission and environmental change: a spatio-temporal analysis in Porto de Galinhas, Pernambuco--Brazil

BACKGROUND

In Brazil, schistosomiasis mansoni infection is an endemic disease that mainly affects the country's rural populations who carry out domestic and social activities in rivers and water accumulations that provide shelter for the snails of the disease. The process of rural migration to urban centers and the disorderly occupation of natural environments by these populations from endemic areas have favored expansion of schistosomiasis to locations that had been considered to be disease-free. Based on environmental changes that have occurred in consequent to an occupation and urbanization process in the locality of Porto de Galinhas, the present study sought to identify the relationship between those chances, measure by remote-sensing techniques, and establish a new endemic area for schistosomiasis on the coast of Pernambuco State--Brazil.

METHODS

To gather prevalence data, two parasitological census surveys were conducted (2000 and 2010) using the Kato-Katz technique. Two malacological surveys were also conducted in the same years in order to define the density and infection rate of the intermediate host. Based on these data, spatial analyses were done, resulting in maps of the risk of disease transmission. To ascertain the environmental changes that have occurred at the locality, images from the QuickBird satellite were analyzed, thus resulting in land use maps.

RESULTS

Over this 10-year period, the foci of schistosomiasis became more concentrated in the Salinas district. This area was considered to be at the greatest risk of schistosomiasis transmission and had the highest prevalence rates over this period. The study illustrated that this was the area most affected by the environmental changes resulting from the disorderly urbanization process, which gave rise to unsanitary environments that favored the establishment and maintenance of foci of schistosomiasis transmission, thereby consolidating the process of expansion and endemization of this parasitosis.

The prevalence of schistosomiasis in school-aged children as an appropriate indicator of its prevalence in the community

School-aged children (6-15 years) from the endemic area of Pernambuco were evaluated both as a target group for and an indicator of schistosomiasis control in the community. Parasitological data were drawn from baseline stool surveys of whole populations that were obtained to diagnose Schistosoma mansoni infection. Nineteen representative localities were selected for assessing the prevalence of schistosomiasis among individuals in the following age groups: 0-5, 6-15, 16-25, 26-40 and 41-80 years. For each locality, the prevalence in each age group was compared to that of the overall population using contingency table analysis. To select a reference group, the operational difficulties of conducting residential surveys were considered. School-aged children may be considered to be the group of choice as the reference group for the overall population for the following reasons: (i) the prevalence of schistosomiasis in this age group had the highest correlation with the prevalence in the overall population (r = 0.967), (ii) this age group is particularly vulnerable to infection and plays an important role in parasite transmission and (iii) school-aged children are the main target of the World Health Organization in terms of helminth control. The Schistosomiasis Control Program should consider school-aged children both as a reference group for assessing the need for intervention at the community level and as a target group for integrated health care actions of the Unified Health System that are focused on high-risk groups.

Spatial pattern, water use and risk levels associated with the transmission of schistosomiasis on the north coast of Pernambuco, Brazil

This study aimed to describe epidemiological aspects of schistosomiasis in Carne de Vaca, Goiana, on the coast of Pernambuco State, Brazil and analyze the spatial distribution of households' sanitary conditions and patterns of water contact. A parasitological survey was conducted between 2006 and 2007. An indicator was set to establish risk levels for schistosomiasis based on variables of water contact pattern, household characteristics and proximity to the foci of vector snails. The prevalence was 18.71 in men and 15.96 in women. The age groups most affected were 20-29 years among men and 10-19 among women. The most common parasite load was 1-99 eggs per gram of feces. The prevalence was 17.3 cases per 100 inhabitants and its spatial distribution was not homogeneous. The Bayesian analysis proved unsatisfactory. It is concluded that schistosomiasis is endemic in Carne de Vaca and the risk indicator, based on geoprocessing, proved to be satisfactory, highlighting areas where the problem is more acute.

O programa de controle da esquistossomose em dois municípios da zona da mata de Pernambuco: uma análise de implantação

OBJETIVOS: conhecer os fatores intervenientes na variação do grau de implantação (GI) do Programa de Controle da Esquistossomose (PCE) em dois municípios de Pernambuco. MÉTODOS: análise de implantação, que avaliou a influência do contexto no GI do PCE. Utilizaram-se questionários estruturados que foram aplicados aos coordenadores do PCE, aos secretários de saúde, coordenadores e agentes de saúde ambiental. Também foram pesquisados registros oficiais e realizou-se observação direta. Empregou-se um sistema de escores que classificou o GI do PCE em implantado (90 a 100 pontos), parcialmente implantado (60 a 89 pontos) e não implantado (< 59). RESULTADOS: GI do PCE no município 1 foi 'não implantado' (52,85 pontos) e no município 2 foi 'parcialmente implantado' (63,65 pontos). Os principais empecilhos para a implantação das ações de controle da esquistossomose foram pouco conhecimento sobre o funcionamento do PCE, planejamento precário das ações de controle, pouca prioridade dada ao programa, e estrutura insuficiente, não contemplação de ações de controle em instrumentos de gestão e centralização de ações. CONCLUSÕES: há necessidade de repensar o controle da esquistossomose considerando a descentralização das ações sob a perspectiva da integralidade e equidade, visando superar paradigmas.

[Temporary and permanent breeding sites for Biomphalaria in Jaboatão dos Guararapes, PE]

A malacological survey of permanent and temporary breeding sites was conducted in the Piedade neighborhood of Jaboatão dos Guararapes, Pernambuco, between November 2006 and November 2007, with the aim of determining the malacological fauna at this locality, along with the potential for Schistosomiasis mansoni transmission. In addition to Biomphalaria glabrata (Say, 1818), the molluscs Drepanotrema cimex (Moricand, 1837), Pomacea sp and Melanoides tuberculatus (Muller, 1774) were collected. Among the specimens of Biomphalaria glabrata that were collected, 1,490 were found alive, and 74 (5%) were positive for Schistosoma mansoni. The largest numbers of molluscs collected, and all of the specimens that were positive for Schistosoma mansoni, were collected during the annual rainy season. The presence of larvae of other trematodes infecting the Biomphalaria glabrata molluscs was also observed. These trematodes were from the families Strigeidae and Diplostomatidae and, at first sight, they presented morphology that could lead to confusion with Schistosoma mansoni cercariae. Thus, knowledge of these trematodes becomes essential for the differential diagnosis of the etiological agent for schistosomiasis.

Assessment of schistosomiasis, through school surveys, in the Forest Zone of Pernambuco, Brazil

This work had the objective of assessing the present epidemiological situation regarding schistosomiasis through performing Kato-Katz coproscopic tests on representative samples of schoolchildren from each of the 43 municipality of endemic area of the state of Pernambuco, Brazil. The methodology is recommended by the World Health Organization to conduct sampled surveys among children at elementary school levels, ideal target group for baseline surveys: (i) schools are accessible; (ii) the greatest prevalence of schistosomiasis is found within this group; (iii) the data gathered from this age group can be used for intervention within the community as a whole. The following infection indicators were utilized: positivity (percentage of individuals examined with eggs of Schistosoma mansoni in the feces) and severity (geometric mean number of eggs per gram of feces, epg). These indicators allowed the area in general and the municipalities in particular to be categorized into prevalence and severity classes for S. mansoni. The prevalence classes were: low (<10%), medium (> 10 and < 50%), and high (> 50%); the severity classes were: low (1-99 epg), moderate (100-399 epg), and severe (> 400 epg). For the geohelminthic diseases, the following indicators were used: positivity for each geohelminth (percentage of individuals examined with eggs of geohelminths), and cumulative positivity (percentage of individuals examined with eggs of at least one geohelminth). The municipalities were categorized by means of their cumulative positivity into the following geohelminth prevalence classes (WHO 2002): low (< 50%), medium (> 50 and < 70%), and high (> 70%). The study covered 271 schools in 179 different localities, thus giving a total of 11,234 examinations performed. The overall positivity for S. mansoni was 14.4% and the egg count for this parasite in the feces gave a geometric mean of 67.9 epg which suggests a low general state of infection. These results allow this mesoregion to be categorized as presenting medium prevalence and low severity of schistosomiasis. The overall positivity rates for the geohelminths, Ascaris lumbricoides, Ancylostomidae, and Trichuris trichiura were, respectively, 30.4, 10.1, and 27.8%; the cumulative positivity was 45.4%. These results allow this mesoregion to be categorized as presenting low prevalence of geohelminthic diseases. The data show some municipalities in Pernambuco with prevalence greater than 20%, while others presented parasite loads greater than 100 epg. These indicators attest to the significant morbidity due to schistosomiasis regarding to the severity of infections established in young populations.

[Spatial analysis of Biomphalaria glabrata foci and human cases of mansoni schistosomiasis in Porto de Galinhas, Pernambuco State, Brazil, in the year 2000]

This article provides information on the spatial distribution of schistosomiasis, correlating snail foci with human cases using spatial analysis. The locations studied were Merepe III, Pantanal, Salinas, and Socó, comprising 70% of the populated area of Porto de Galinhas. Malacological and parasitological surveys by a CPqAM/ FIOCRUZ team at the location where an epidemic occurred in 2000 identified 15 foci of infected B. glabrata. Human cases were also diagnosed and recorded according to residential block. Spatial analysis was performed using the TerraView computer program and Kernel intensity estimation. Total infection rates, considering all collection stations marked out per location, varied from 15% to 32.4%. The 15 infected B. glabrata foci included 9 in Merepe, 2 in Socó, 3 in Salinas, and 1 in Pantanal. The results suggest a strong spatial trend in the risk of schistosomiais transmission in Salinas and Socó. In Merepe, with the most foci and where foci were closer together, individual focal infection rates were lower. Spatial analysis thus showed less concentration of risk as compared to other locations studied. As for human cases, two high-intensity areas were observed, shown on the map in darker colors.

Clinical-epidemiological profile of children with schistosomal myeloradiculopathy attended at the Instituto Materno-Infantil de Pernambuco

The most critical phase of exposure to schistosomal infection is the infancy, because of the more frequent contact with contaminated water and the immaturity of the immune system. One of the most severe presentations of this parasitosis is the involvement of the spinal cord, which prognosis is largely dependent on early diagnosis and treatment. Reports on this clinical form of schistosomiasis in children are rare in the literature. We present here the clinical-epidemiological profile of schistosomal myeloradiculopathy (SMR) from ten children who were admitted at the Instituto Materno-Infantil de Pernambuco over a five-year period. They were evaluated according to an investigation protocol. Most of these patients presented an acute neurological picture which included as the main clinical manifestations: sphincteral disorders, low back and lower limbs pain, paresthesia, lower limbs muscle weakness and absence of deep tendon reflex, and impairment of the gait. The diagnosis was presumptive in the majority of the cases. This study emphasizes the importance of considering the diagnosis of SMR in pediatric patients coming from endemic areas who present a low cord syndrome, in order to start the appropriate therapy and avoid future complications.

[Hospitalization and mortality from mansoni schistosomiasis in the state of Pernambuco, Brazil, 1992/2000]

In order to investigate the historical trends, epidemiological profile, and spatial distribution of hospital admissions and deaths from schistosomiasis in the State of Pernambuco, Brazil, an analysis was conducted of data from the Hospital Information System and Mortality Information System from 1992 to 2000. The results showed a reduction in hospital admissions and mortality, while identifying more admissions and deaths among males. There was a lower percentage of deaths and admissions from schistosomiasis in individuals under 30 years of age. However, schistosomiasis is still of relevant magnitude, as evidenced by the number of deaths from this cause and the number of patients admitted to the hospital system in Pernambuco. A spatial analysis of the endemic's distribution in the State showed that although from 1995 to 1999 there was a greater spread of admissions due to schistosomiasis in the municipalities (counties) of the Sertão (backlands) and São Francisco river valley, the number of municipalities with hospitalizations due to schistosomiasis decreased from 1995 to 1998, followed by an increase in 1999 and 2000.

Mulheres de Camaragibe: representação social sobre a vulnerabilidade feminina em tempos de AIDS

OBJETIVOS: compreender a representação social que mulheres casadas, em situação de pobreza, possuem acerca da AIDS. Dessa forma, se espera contribuir para que o enfrentamento da epidemia se dê de forma mais sintonizada com a realidade em que essa acontece. MÉTODOS: foram realizadas 16 entrevistas, com mulheres em situação de pobreza, com relação conjugal estável. Essas entrevistas foram gravadas, transcritas e agrupadas segundo critérios de avaliação e análise. A análise foi feita com base na proposta da hermenêutica, que se refere à leitura das entrelinhas. RESULTADOS: foi observado um aumento da vulnerabilidade feminina frente à infecção pelo HIV/AIDS, baseado na representação social que essas mulheres têm da AIDS, visto que suas percepções acabam por lhes fornecer uma falsa sensação de imunidade, pois elas não se encaixam dentro do perfil que imaginam como sendo de quem apresenta o vírus ou a própria doença. CONCLUSÕES: o perfil epidemiológico atual da AIDS aponta a mulher como alvo da infecção. Isso ocorre principalmente através das relações sexuais, que são ditadas pelas relações de gênero. Para elas a AIDS é um mal distante; se próximo, não lhes pertence, se lhes pertence é legitimado por ser "obra de Deus" ou por ser próprio do papel de esposa.

Spatial distribution of schistosomiasis foci on Itamaracá Island, Pernambuco, Brazil

Acute cases of schistosomiasis have been found on the coastal area of Pernambuco, Brazil, due to environmental disturbances and disorderly occupation of the urban areas. This study identifies and spatially marks the main foci of the snail host species, Biomphalaria glabrata on Itamaracá Island. The chaotic occupation of the beach resorts has favoured the emergence of transmission foci, thus exposing residents and tourists to the risk of infection. A database covering five years of epidemiological investigation on snails infected by Schistosoma mansoni in the island was produced with information from the geographic positioning of the foci, number of snails collected, number of snails tested positive, and their infection rate. The spatial position of the foci were recorded through the Global Positioning System (GPS), and the geographical coordinates were imported by AutoCad. The software packages ArcView and Spring were used for data processing and spatial analysis. AutoCad 2000 was used to plot the pairs of coordinates obtained from GPS. Between 1998 and 2002 5009 snails, of which 12.2% were positive for S. mansoni, were collected in Forte Beach. A total of 27 foci and areas of environmental risk were identified and spatially analyzed allowing the identification of the areas exposed to varying degrees of risk.