[Show abstract][Hide abstract] ABSTRACT: SUMO-dependent post-translational modification is implicated in a variety of cellular functions including gene expression regulation, nuclear sub-localization, and signal transduction. Conjugation of SUMO to other proteins occurs in a similar process to ubiquitination, which involves three classes of enzymes: an E1 activating, an E2 conjugating, and an E3 target-specific ligase. Ubc9 is the unique SUMO E2 enzyme known to conjugate SUMO to target substrates. Here, we present the molecular characterization of this enzyme and demonstrate its expression profile during the S. mansoni life cycle. We have used bioinformatic approaches to identify the SUMO-conjugating enzyme, the SmUbc9-like protein, in the Schistosoma mansoni databases. Quantitative RT-PCR was employed to measure the transcript levels of SUMO E2 in cercariae, adult worms, and in vitro cultivated schistosomula. Furthermore, recombinant SmUbc9 was expressed using the Gateway system, and antibodies raised in rats were used to measure SmUbc9 protein levels in S. mansoni stages by Western blotting. Our data revealed upregulation of the SmUbc9 transcript in early schistosomula followed by a marked differential gene expression in the other analyzed stages. The protein levels were maintained fairly constant suggesting a post-transcriptional regulation of the SmUbc9 mRNA. Our results show for the first time that S. mansoni employs a functional SUMO E2 enzyme, for the conjugation of the SUMO proteins to its target substrates.
Parasitology Research 05/2011; 109(6):1537-46. DOI:10.1007/s00436-011-2394-4 · 2.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Schistosomiasis mansoni is endemic in 54 countries in the Americas and Africa. In Brazil, it is estimated that 4 to 6 million people are infected. Despite advances in knowledge in the field of schistosomiasis, the disease remains a serious public health problem in the country, requiring greater investments in preventive measures such as sanitation and health education. The use of Geographic Information Systems (GIS) tools help to map and understand the spatial distribution of the disease. This study used the geostatistical tool (kriging) of the Georeferenced Information Processing System (SPRING) to estimate the prevalence of schistosomiasis in areas without information. The resulting map was a regular grid of 1 km in the endemic area. The average prevalence per municipality was estimated by kriging and it was compared with the prevalence of Brazilian Schistosomiasis Control Program (PCE) in 255 municipalities. With a significance level of 0.05, it was found that there is no significant difference between the average prevalence estimated and obtained. The kriging can be used to estimate the prevalence of schistosomiasis in the municipalities of the State of Minas Gerais where the prevalence was not determined by the PCE. The results of this tool can be used to better allocate resources for studies in areas with medium and high prevalence. Palavras-chave: GIS, schistosomiasis, krig, SIG, esquistossomose, krigeagem.
XV Simpósio Brasileiro de Sensoriamento Remoto - SBSR, Curitiba, PR; 04/2011
[Show abstract][Hide abstract] ABSTRACT: The increasing practice of ecotourism and rural tourism in the State of Minas Gerais, Brazil, highlights the importance of studies concerning the occurrence of potential intermediate hosts of Schistosoma mansoni. This study aimed to identify species of Biomphalaria snails in municipalities along the Estrada Real, an important Brazilian tourism project.
The specimens were collected in different water collections of 36 municipalities along the Estrada Real in the southeast of the State of Minas Gerais. Biomphalaria species were characterized using both morphological and molecular approaches. The research was conducted between August 2005 and September 2009 and all the sites visited were georeferenced using GPS.
Six Biomphalaria species were found in 30 of the 36 municipalities studied: glabrata, tenagophila, straminea, peregrina, occidentalis and schrammi. The first three species of Biomphalaria, recognized as intermediate hosts of S. mansoni, were present in 33.3%, 47.2% and 8.3% of the municipalities studied, respectively. The mollusks were found in different types of water collections and no infection by S. mansoni was detected. The highest occurrence of Biomphalaria concentration was verified in the area covered by the Caminho Novo route (Diamantina/MG to Rio de Janeiro/RJ).
Considering the occurrence of schistosomiasis in the State of Minas Gerais and the socioeconomic repercussions involved in the Estrada Real Project, this work focuses on the vulnerability of water collections due to the presence of Biomphalaria mollusks and emphasizes the need for epidemiological surveillance and sanitary and educational measures integrated with the local community and tourism sectors.
Revista da Sociedade Brasileira de Medicina Tropical 03/2011; 44(2):163-7. DOI:10.1590/S0037-86822011005000005 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In Brazil, there are three intermediate snail vectors and two potential hosts of Schistosoma mansoni. Previous studies showed three variant molecular profiles to B. amazonica and evidenced intraspecific variations using sequence data. In this context, the aim of this study was to verify whether such differences would correspond to either B. amazonica or B. cousini. The snails were morphologically identified; PCR-RFLP and sequencing were carried out. Besides, B. cousini were submitted to susceptibility experiments to S. mansoni. Noteworthy, morphological data of Brazilian specimens predominantly showed the morphology described for B. amazonica. Nevertheless, PCR-RFLP results exhibited three variant molecular profiles for the specimens previously identified as B. amazonica and the phylogenetic analyses showed two groups one to B. amazonica and another to B. cousini. Furthermore, B. cousini showed to be susceptible to S. mansoni. These results confirm the occurrence of B. cousini in Brazil and points to the risk of introduction of schistosomiasis mansoni into new areas.
[Show abstract][Hide abstract] ABSTRACT: The human cases of eosinophilic meningitis recently reported from Brazil have focused the attention of the public health agencies on the role the introduced snail Achatina fulica plays as hosts of the metastrongylid nematodes. Determining the potential of this snail to host and develop infective larval stages of metastrongylids in the wild and identify the species harbored by them is crucial for designing effective control measures. Here we assess if A. fulica may act as intermediate host of A. cantonensis at the peridomiciliary areas of a patient's house from state of Pernambuco (PE), who was diagnosed with eosinophilic meningitis and a history of ingesting raw molluscs. Larvae obtained from naturally infected A. fulica were orally administered to Rattus norvegicus. The worms were collected from the pulmonary artery and brain, and were morphologically characterized and compared to the Japan isolate of A. cantonensis. Adult worms and infective L(3) larvae (PE isolate) recovered from A. fulica specimens were also analyzed by polymerase chain reaction and restriction fragment length polymorphism of ITS2 region from rDNA and compared to A. cantonensis (ES isolate), A. vasorum (MG isolate) and A. costaricensis (RS isolate). The large size of the spicules (greater than those observed in other species of Angiostrongylus) and the pattern of the bursal rays agree with the original species description by Chen (1935). Furthermore, the morphology of the PE isolate was similar to that of Japan isolate. The PCR-RFLP profiles obtained were distinctive among species and no variation in patterns was detected among adult individuals from A. cantonensis isolates from PE and ES. The importance of A. fulica as an intermediate host of eosinophilic menigoencepahlitis in Brazil is emphasized.
[Show abstract][Hide abstract] ABSTRACT: Geographical Information System (GIS) is a tool that has recently been applied to better understand spatial disease distributions. Using meteorological, social, sanitation, mollusc distribution data and remote sensing variables, this study aimed to further develop the GIS technology by creating a model for the spatial distribution of schistosomiasis and to apply this model to an area with rural tourism in the Brazilian state of Minas Gerais (MG). The Estrada Real, covering about 1,400 km, is the largest and most important Brazilian tourism project, involving 163 cities in MG with different schistosomiasis prevalence rates. The model with three variables showed a R(2) = 0.34, with a standard deviation of risk estimated adequate for public health needs. The main variables selected for modelling were summer vegetation, summer minimal temperature and winter minimal temperature. The results confirmed the importance of Remote Sensing data and the valuable contribution of GIS in identifying priority areas for intervention in tourism regions which are endemic to schistosomiasis.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):532-6. DOI:10.1590/S0074-02762010000400031 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Praziquantel chemotherapy has been the focus of the Schistosomiasis Control Program in Brazil for the past two decades. Nevertheless, information on the impact of selective chemotherapy against Schistosoma mansoni infection under the conditions confronted by the health teams in endemic municipalities remains scarce. This paper compares the spatial pattern of infection before and after treatment with either a 40 mg/kg or 60 mg/kg dose of praziquantel by determining the intensity of spatial cluster among patients at 180 and 360 days after treatment. The spatial-temporal distribution of egg-positive patients was analysed in a Geographic Information System using the kernel smoothing technique. While all patients became egg-negative after 21 days, 17.9% and 30.9% reverted to an egg-positive condition after 180 and 360 days, respectively. Both the prevalence and intensity of infection after treatment were significantly lower in the 60 mg/kg than in the 40 mg/kg treatment group. The higher intensity of the kernel in the 40 mg/kg group compared to the 60 mg/kg group, at both 180 and 360 days, reflects the higher number of reverted cases in the lower dose group. Auxiliary, preventive measures to control transmission should be integrated with chemotherapy to achieve a more enduring impact.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):555-62. DOI:10.1590/S0074-02762010000400035 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Schistosomiasis mansoni is not just a physical disease, but is related to social and behavioural factors as well. Snails of the Biomphalaria genus are an intermediate host for Schistosoma mansoni and infect humans through water. The objective of this study is to classify the risk of schistosomiasis in the state of Minas Gerais (MG). We focus on socioeconomic and demographic features, basic sanitation features, the presence of accumulated water bodies, dense vegetation in the summer and winter seasons and related terrain characteristics. We draw on the decision tree approach to infection risk modelling and mapping. The model robustness was properly verified. The main variables that were selected by the procedure included the terrain's water accumulation capacity, temperature extremes and the Human Development Index. In addition, the model was used to generate two maps, one that included risk classification for the entire of MG and another that included classification errors. The resulting map was 62.9% accurate.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):541-8. DOI:10.1590/S0074-02762010000400033 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mitochondrial DNA of Biomphalaria tenagophila, a mollusc intermediate host of Schistosoma mansoni in Brazil, was sequenced and characterised. The genome size found for B. tenagophila was 13,722 bp and contained 13 messenger RNAs, 22 transfer RNAs (tRNA) and two ribosomal RNAs (rRNA). In addition to sequencing, the mitochondrial DNA (mtDNA) genome organization of B. tenagophila was analysed based on its content and localization of both coding and non-coding regions, regions of gene overlap and tRNA nucleotide sequences. Sequences of protein, rRNA 12S and rRNA 16S nucleotides as well as gene organization were compared between B. tenagophila and Biomphalaria glabrata, as the latter is the most important S. mansoni intermediate host in Brazil. Differences between such species were observed regarding rRNA composition. The complete sequence of the B. tenagophila mitochondrial genome was deposited in GenBank (accession EF433576). Furthermore, phylogenetic relationships were estimated among 28 mollusc species, which had their complete mitochondrial genome deposited in GenBank, using the neighbour-joining method, maximum parsimony and maximum likelihood bootstrap. B. tenagophila was positioned at a branch close to B. glabrata and Pulmonata molluscs, collectively comprising a paraphyletic group, contrary to Opistobranchia, which was positioned at a single branch and constituted a monophyletic group.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):504-11. DOI:10.1590/S0074-02762010000400027 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper analyses the associations between Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) on the prevalence of schistosomiasis and the presence of Biomphalaria glabrata in the state of Minas Gerais (MG), Brazil. Additionally, vegetation, soil and shade fraction images were created using a Linear Spectral Mixture Model (LSMM) from the blue, red and infrared channels of the Moderate Resolution Imaging Spectroradiometer spaceborne sensor and the relationship between these images and the prevalence of schistosomiasis and the presence of B. glabrata was analysed. First, we found a high correlation between the vegetation fraction image and EVI and second, a high correlation between soil fraction image and NDVI. The results also indicate that there was a positive correlation between prevalence and the vegetation fraction image (July 2002), a negative correlation between prevalence and the soil fraction image (July 2002) and a positive correlation between B. glabrata and the shade fraction image (July 2002). This paper demonstrates that the LSMM variables can be used as a substitute for the standard vegetation indices (EVI and NDVI) to determine and delimit risk areas for B. glabrata and schistosomiasis in MG, which can be used to improve the allocation of resources for disease control.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):512-8. DOI:10.1590/S0074-02762010000400028 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Geographical information systems (GIS) are tools that have been recently tested for improving our understanding of the spatial distribution of disease. The objective of this paper was to further develop the GIS technology to model and control schistosomiasis using environmental, social, biological and remote-sensing variables. A final regression model (R(2) = 0.39) was established, after a variable selection phase, with a set of spatial variables including the presence or absence of Biomphalaria glabrata, winter enhanced vegetation index, summer minimum temperature and percentage of houses with water coming from a spring or well. A regional model was also developed by splitting the state of Minas Gerais (MG) into four regions and establishing a linear regression model for each of the four regions: 1 (R(2) = 0.97), 2 (R(2) = 0.60), 3 (R(2) = 0.63) and 4 (R(2) = 0.76). Based on these models, a schistosomiasis risk map was built for MG. In this paper, geostatistics was also used to make inferences about the presence of Biomphalaria spp. The result was a map of species and risk areas. The obtained risk map permits the association of uncertainties, which can be used to qualify the inferences and it can be thought of as an auxiliary tool for public health strategies.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):524-31. DOI:10.1590/S0074-02762010000400030 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Specific genetic profiles of Brazilian Biomphalaria species were previously standardized by molecular taxonomy through the analysis of restriction fragments, which were generated by digesting the internal transcribed spacer region of rDNA with the DdeI endonuclease. Biomphalaria amazonica displayed three distinct profiles. To investigate these distinct profiles, the same molecular technique, polymerase chain reaction and restriction fragment length polymorphism, was used with different endonucleases. In addition, morphological data were also used to compare B. amazonica specimens that were collected from Brazil, Colombia and Bolivia. The morphological characters of Bolivian molluscs were similar to B. amazonica, displayed a molecular profile of five restriction fragments and morphological data, whereas the Colombian mollusc population showed morphological characters similar to Biomphalaria cousini and a molecular profile of three restriction fragments, similar to B. cousini. The Brazilian specimens showed the B. amazonica and B. cousini molecular profiles as well as a third profile, which resembled a combination of the Colombian and Bolivian molecular profiles.
Memórias do Instituto Oswaldo Cruz 07/2010; 105(4):485-7. DOI:10.1590/S0074-02762010000400022 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Schistosomiasis mansoni is a disease with social and behavioral characteristics. Snails of the Biomphalaria species, the disease's intermediate host, use water as a vehicle to infect man, the disease main host. In Brazil, six million people are infected. From 1995 to 2005, more than a million positive cases were reported, 27% of them in the state of Minas Gerais. The objective of this paper is to estimate the prevalence risk of schistosomiasis, in terms of remote sensing, climate, socioeconomic, or neighborhood variables or a subset of them. We present two approaches for modeling and classifying the infection risk: a global and a regional one, both of them using the aforementioned variables. In the first approach, a unique regression model was generated and used to estimate the disease risk for the entire state. In the second approach, the state was divided in four regions, and a model was generated for each of them. The first model obtained 47.2% of overall accuracy (AC) and the second achieved 62.4%, which were considered unsatisfactory. To improve these results, the concept of imprecise classification, defined in terms of the standard deviation of estimates and several reliability levels, is used for the generation of two imprecise classification maps. The AC for the imprecise classification was 83.8% for the global model and 91.9% for the regional one, which were now considered acceptable. Particularly, regionalization has proven to be a good guideline to follow in future works involving geographical aspects and large data heterogeneity.
IEEE Transactions on Geoscience and Remote Sensing 11/2009; 47(11):3899-3908. DOI:10.1109/TGRS.2009.2028332 · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The three vector species of Schistosoma mansoni in Brazil, Biomphalaria glabrata, B. tenagophila and B. straminea show different susceptibility levels to the trematode besides a wide geographical distribution. The identification of such molluscs is important to further understand the disease epidemiology. Considering the fact that morphological identification may become difficult or even impossible under particular circumstances, the use of molecular-based methods have permitted the generation of more consistent information concerning the population structure of Biomphalaria furthering knowledge on taxonomy and diagnosis of infection. We have developed methodologies in order to provide simultaneous species identification of the intermediate host and diagnosis of infection with S. mansoni.
[Show abstract][Hide abstract] ABSTRACT: In Brazil, there are near 20 genera and almost 120 species of scorpions of which 95% reproduce sexually. Parthenogenetic reproduction, however, may also take place. To gain insight into useful molecular markers in parthenogenetic scorpion species, we studied DNA polymorphism using two molecular approaches: simple sequence repeat anchored polymerase chain reaction (SSR-PCR) and sequencing of the cytochrome C oxidase subunit I of the mitochondrial genome, mtDNA (COXI), of Tityus serrulatus. Three different groups were used: group 1, composed of 1 female and 14 descendants; group 2 with 1 female and 17 descendants, both from the city of Uberlândia, State of Minas Gerais (MG), Brazil, and the third group that consisted of three adult scorpions from the city of Belo Horizonte, MG. The profiles generated by SSR-PCR were identical for all specimens, while partial sequencing of COXI showed the presence of SNPs. After aligning COXI contigs, one of the groups presented 18 SNPs and the second 8 SNPs. The two groups were differentiated by two diagnostic SNPs. We did not find evidence of mitochondrial recombination. The results are in agreement with the parthenogenetic mode of reproduction of this species and sequencing of the COXI gene enabled the separation of scorpions groups.
[Show abstract][Hide abstract] ABSTRACT: The present study was aimed at characterising Biomphalaria species using both morphological and molecular (PCR-RFLP) approaches. The specimens were collected in 15 localities in 12 municipalities of the southern region of the state of Rio Grande do Sul, Brazil. The following species were found and identified: Biomphalaria tenagophila guaibensis, Biomphalaria oligoza and Biomphalaria peregrina. Specimens of the latter species were experimentally challenged with the LE Schistosoma mansoni strain, which showed to be refractory to infection.
Memórias do Instituto Oswaldo Cruz 08/2009; 104(5):783-6. DOI:10.1590/S0074-02762009000500020 · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Schistosomiasis control programs in Brazil have helped reduce prevalence and the severe forms of the disease, but have failed to prevent new foci from appearing, especially on the periphery of large cities. The current article aims to assess the prevalence of schistosomiasis and the presence of intermediates hosts for Schistosoma mansoni in the district of Ravena, Municipality of Sabará, Minas Gerais State, Brazil, 27 years after implementing water treatment and specific treatment for infected individuals. Ravena responded positively to schistosomiasis control measures, with a prevalence of 2.5%. However, the district remains a potential risk area, since it displays favorable environmental and ecological factors for maintenance of the disease. For the prevalence rates to continue low, it will be necessary to invest in sanitation and health education, in addition to treatment of infected individuals.
Cadernos de saúde pública / Ministério da Saúde, Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública 06/2009; 25(5):997-1006. · 0.98 Impact Factor