Comparative analysis of rapid agglutination latex test using single-chain antibody fragments (scFv) versus the gold standard Vero cell assay for Shiga toxin (Stx) detection.

The latex agglutination test using single-chain antibody fragments (scFvStx1 and scFvStx2) coupled to latex particles, was compared with the gold standard Vero cell assay for Shiga toxin (Stx) detection, aiming to estimate the diagnosis potential of these scFv fragments in a rapid and straightforward test. The latex complexes identified the presence of the toxins up to a 1:8 dilution in the majority of the evaluated strains. Moreover, the Stx concentration was indirectly determined in Stx-producing Escherichia coli (STEC) strains, allowing detection limit inference. A Stx dilution curve was constructed, and the data was analyzed in a non-linear model by second-order polynomial regression for prediction (p-value of 0.001 and a R2 above 0.98 were considered for correlations). The detection limit was 30 ng/mL for Stx1 and 10 ng/mL for Stx2. The scFvStx1 and scFvStx2 coupled to latex nanoparticles provide a toxin assay with a competitive Stx detection limit, which has a low cost and short execution time. The diagnostic method proposed here, using, for the first time, recombinant antibody fragments, raises the possibility of developing a more affordable test to be used in the routine detection and surveillance of STEC infections.

Synthesis, characterization and applications of maghemite beads functionalized with rabbit antibodies.

Magnetic nanoparticles (NPs) have attracted great attention owing to their applications in the biomedical field. In the present work, maghemite (γFe2O3) NPs of 6.5 nm were prepared using a sonochemical method and used to prepare magnetic beads through silanization with 3-aminopropyltrimethoxysilane (APTS). Subsequently, amino groups in the resulting APTS-γFe2O3 beads were converted to carboxylic acid (CARB-γFe2O3) through the succinic anhydride reaction, as confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and dynamic light scattering (DLS) measurements. The size of these beads was measured as 12 nm and their hydrodynamic diameter as 490 nm, using TEM analysis and DLS, respectively. The CARB-γFe2O3 beads were further functionalized by immobilizing rabbit antibodies on their surfaces; the immobilization was confirmed by flow cytometry and ionic strength. The samples were further characterized by Mössbauer spectroscopy and DC magnetization measurements. Studies on magnetic relaxivities showed that magnetic beads present great potential for application in MR imaging.

ppGpp and cytotoxicity diversity in Shiga toxin-producing Escherichia coli (STEC) isolates.

Shiga toxin-producing Escherichia coli (STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across the E. coli species. In the present study, 50 STEC isolates from healthy sheep were evaluated regarding their ppGpp content, cytotoxicity and other relevant genetic and phenotypic characteristics. We found that the level of ppGpp and cytotoxicity varied considerably among the examined strains. Isolates that harboured the stx2 gene were the least cytotoxic and presented the highest levels of ppGpp. All stx2 isolates belonged to phylogroup A, while strains that carried stx1 or both stx1 and stx2 genes pertained to phylogroup B1. All but two stx2 isolates belonged to the stx2b subtype. Strains that belonged to phylogroup B1 displayed on average low levels of ppGpp and high cytotoxicity. Overall, there was a negative correlation between cytotoxicity and ppGpp.

Immunization of mice with Lactobacillus casei expressing a beta-intimin fragment reduces intestinal colonization by Citrobacter rodentium

countries. Intimate adhesion of the bacteria to intestinal cells occurs via binding of the adhesin intimin to theTIR receptor exposed on cell surfaces. Here, Lactobacillus casei expressing a fragment of -intimin (L.casei-Intcv) was tested as mucosal vaccines in mice against intestinal colonization with the murine pathogenCitrobacter rodentium. Oral or sublingual immunization of C57BL/6 mice with L. casei-Intcv induced anti-IntcvIgA in feces but no IgG in sera. Conversely, anti-Intcv IgG was induced in the sera of mice after sublingualimmunization with purified Intcv. All vaccines were able to decrease C. rodentium recovery from feces. However,this reduction was more evident and sustained over time in mice immunized with L. casei-Intcv by thesublingual route. These mice also displayed an increase in interleukin 6 (IL-6) and gamma interferon (IFN- )secretion by spleen cells 10 days after infection. Additionally, oral or sublingual immunization of C3H/HePasmice, which are highly susceptible to C. rodentium infection, with L. casei-Intcv induced anti-Intcv antibodiesand significantly increased survival after challenge. Immunohistological analysis of colon sections revealedthat C. rodentium was located in deep fractions of the tissue from C3H/HePas mice immunized with L. casei whereas superficial staining was observed in colon sections from mice immunized with L. casei-Intcv. The results indicate that vaccines composed of L. casei expressing intimin may represent a promising approach and that the C3H/HePas infection model with C. rodentium can be used to evaluate potential vaccines against EPEC.

Immunization of mice with Lactobacillus casei expressing a beta-intimin fragment reduces intestinal colonization by Citrobacter rodentium.

Enteropathogenic Escherichia coli (EPEC) is a common cause of diarrhea in children from developing countries. Intimate adhesion of the bacteria to intestinal cells occurs via binding of the adhesin intimin to the TIR receptor exposed on cell surfaces. Here, Lactobacillus casei expressing a fragment of ß-intimin (L. casei-Int(cv)) was tested as mucosal vaccines in mice against intestinal colonization with the murine pathogen Citrobacter rodentium. Oral or sublingual immunization of C57BL/6 mice with L. casei-Int(cv) induced anti-Int(cv) IgA in feces but no IgG in sera. Conversely, anti-Int(cv) IgG was induced in the sera of mice after sublingual immunization with purified Int(cv). All vaccines were able to decrease C. rodentium recovery from feces. However, this reduction was more evident and sustained over time in mice immunized with L. casei-Int(cv) by the sublingual route. These mice also displayed an increase in interleukin 6 (IL-6) and gamma interferon (IFN-γ) secretion by spleen cells 10 days after infection. Additionally, oral or sublingual immunization of C3H/HePas mice, which are highly susceptible to C. rodentium infection, with L. casei-Int(cv) induced anti-Int(cv) antibodies and significantly increased survival after challenge. Immunohistological analysis of colon sections revealed that C. rodentium was located in deep fractions of the tissue from C3H/HePas mice immunized with L. casei whereas superficial staining was observed in colon sections from mice immunized with L. casei-Int(cv.) The results indicate that vaccines composed of L. casei expressing intimin may represent a promising approach and that the C3H/HePas infection model with C. rodentium can be used to evaluate potential vaccines against EPEC.

Identification of enteropathogenic and enterohaemorrhagic Escherichia coli strains by immunoserological detection of intimin.

AIMS: To evaluate the sensitivity and specificity of polyclonal and monoclonal antibodies (Mabs) against intimin in the detection of enteropathogenic and enterohaemorrhagic Escherichia coli isolates using immunoblotting. METHODS AND RESULTS: Polyclonal and Mabs against the intimin-conserved region were raised, and their reactivities were compared in enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) isolates using immunoblotting analysis. In comparison with rat antiserum, rabbit anti-intimin IgG-enriched fraction had a stronger recognition pattern to a wide spectrum of intimin types in different EPEC and EHEC serotypes. On the other hand, murine monoclonal IgG2b specific to intimin, with dissociation constant of 1.3x10(-8) mol l(-1), failed in the detection of some of these isolates. CONCLUSION: All employed antibodies showed 100% specificity, not reacting with any of the eae-negative isolates. The sensitivity range was according to the employed antisera, and 97% for rabbit anti-intimin IgG-enriched fraction, followed by 92% and 78% sensitivity with rat antisera and Mab. SIGNIFICANCE AND IMPACT OF THE STUDY: The rabbit anti-intimin IgG-enriched fraction in immunoblotting analysis is a useful tool for EPEC and EHEC diagnoses.

Differentiation of typical and atypical enteropathogenic Escherichia coli using colony immunoblot for detection of bundle-forming pilus expression.

AIMS: The aim of study was to develop a colony immunoblot assay to differentiate typical from atypical enteropathogenic Escherichia coli (EPEC) by detection of bundle-forming pilus (BFP) expression. METHODS AND RESULTS: Anti-BFP antiserum was raised in rabbits and its reactivity was confirmed by immunoelectron microscopy and by immunoblotting recognizing bundlin, the major pilus repeating subunit. The bacterial isolates tested in the colony immunoblot assay were grown in different media. Proteins from bacterial isolates were transferred to nitrocellulose membrane after treatment with phosphate buffer containing Triton X-100, EDTA and sodium chloride salts. When 24 typical EPEC and 96 isolates including, 72 atypical EPEC, 13 Gram-negative type IV-expressing strains and 11 enterobacteriaceae were cultivated in Dulbecco's Modified Eagle's Medium agar containing fetal bovine serum or in blood agar in the presence of CaCl(2) , they showed a positivity of 92 and 83%, and specificity of 96 and 97%, respectively. CONCLUSION: The assay enables reliable identification of BFP-expressing isolates and contributes to the differentiation of typical and atypical EPEC. SIGNIFICANCE AND IMPACT OF THE STUDY: The colony immunoblot for BFP detection developed in this study combines the simplicity of an immunoserological assay with the high efficiency of testing a large number of EPEC colonies.

Differentiation of typical and atypical enteropathogenic Escherichia coli using colony immunoblot for detection of bundle-forming pilus expression

The aim of study was to develop a colony immunoblot assay to differentiatetypical from atypical enteropathogenic Escherichia coli (EPEC) by detectionof bundle-forming pilus (BFP) expression. Anti-BFP antiserum was raised in rabbits and itsreactivity was confirmed by immunoelectron microscopy and by immunoblotting recognizing bundlin, the major pilus repeating subunit. The bacterial isolates tested in the colony immunoblot assay were grown in different media. Proteins from bacterial isolates were transferred to nitrocellulose membrane after treatment with phosphate buffer containing Triton X-100, EDTA and sodium chloride salts. When 24 typical EPEC and 96 isolates including, 72 atypical EPEC, 13 Gram-negative type IV-expressing strains and 11 enterobacteriaceae were cultivated in Dulbecco’s Modified Eagle’s Medium agar containing fetal bovine serum or in blood agar in the presence of CaCl2, they showed a positivity of 92 and 83%, and specificity of 96 and 97%, respectively. The assay enables reliable identification of BFP-expressing isolatesand contributes to the differentiation of typical and atypical EPEC.The colony immunoblot for BFP detectiondeveloped in this study combines the simplicity of an immunoserologicalassay with the high efficiency of testing a large number of EPECcolonies.

Identification of enteropathogenic and enterohaemorrhagic Escherichia coli strains by immunoserological detection of intimin

To evaluate the sensitivity and specificity of polyclonal and monoclonalantibodies (Mabs) against intimin in the detection of enteropathogenic andenterohaemorrhagic Escherichia coli isolates using immunoblotting.Polyclonal and Mabs against the intimin-conservedregion were raised, and their reactivities were compared in enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC) isolates using immunoblotting analysis. In comparison with rat antiserum, rabbit anti-intimin IgG-enriched fraction had a stronger recognition pattern to a wide spectrum of intimin types in different EPEC and EHEC serotypes. On the other hand, murine monoclonal IgG2b specific to intimin, with dissociation constant of1Æ3 · 10)8 mol l)1, failed in the detection of some of these isolates. All employed antibodies showed 100% specificity, not reacting with any of the eae-negative isolates. The sensitivity range was according to the employed antisera, and 97% for rabbit anti-intimin IgG-enriched fraction, followed by 92% and 78% sensitivity with rat antisera and Mab. Significance and Impact of the Study: The rabbit anti-intimin IgG-enriched fraction in immunoblotting analysis is a useful tool for EPEC and EHEC diagnoses.

Adherence and invasion of Bacteroidales isolated from the human intestinal tract.

Members of the genera Bacteroides and Parabacteroides are important constituents of both human and animal intestinal microbiota, and are significant facultative pathogens. In this study, the ability of Bacteroides spp. and Parabacteroides distasonis isolated from both diarrhoeal and normal stools (n = 114) to adhere to and invade HEp-2 cells was evaluated. The presence of putative virulence factors such as capsule and fimbriae was also investigated. Adherence to HEp-2 cells was observed in 75.4% of the strains, which displayed non-localized clusters. Invasion was observed in 37.5% and 26% of the strains isolated from diarrhoeal and non-diarrhoeal stools, respectively. All strains displayed a capsule, whereas none of them showed fimbriae-like structures. This is the first report of the ability of Bacteroides spp. and P. distasonis to adhere to and invade cultured HEp-2 epithelial cells.

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil / Camallanus maculatus n. sp. (Nematoda: Camallanidae) em peixe ornamental Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivado no estado de São Paulo, Brasil

The present study describes Camallanus maculatus n. sp. (Nematoda: Camallanidae) from Xiphophorus maculatus (Osteichthyes: Poecilidae) collected in an ornamental fish farm in São Paulo State, Brazil. Thirty-three out of 40 examined fish were parasitized (82 percent prevalence) with mean intensity of 2.8 (1-20). Male specimens were 3,500µm total length and females 7,100µm total length, provided with orange-brown buccal capsule and two developed tridents. Males showed two unequal spicules, gubernaculum absent and females with vulva situated in the middle of the body. The main characteristics were the sleekly longitudinal ridges in the buccal capsule in both sexes, enlargement at the anterior end of the smaller spicule, the number of genital papillae, longer muscular and glandular portion of esophagus and round tail in female(AU)

Descreve-se Camallanus maculatus n. sp. (Nematoda: Camallanidae) em Xiphophorus maculatus (Osteichthyes: Poecilidae) capturado em uma piscicultura ornamental no estado de São Paulo. De 40 peixes examinados, 33 estavam parasitados (prevalência de 82 por cento) cuja intensidade média foi de 2,8 (1-20). Os machos apresentaram 3.500µm e as fêmeas com 7,100µm de comprimento total, providos de uma cápsula bucal laranja-castanho e dois tridentes. Observaram-se machos com espículos desiguais, gubernáculo ausente e fêmeas com vulva situada na metade do corpo. As principais características foram as estrias longitudinais lisas em cada valva da cápsula bucal em ambos os sexos, o espículo menor com alargamento na extremidade anterior, o número de papilas genitais, as porções muscular e glandular do esôfago longas e a cauda longa e arredondada na fêmea(AU)

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil

The present study describes Camallanus maculatus n. sp. (Nematoda: Camallanidae) from Xiphophorus maculatus (Osteichthyes: Poecilidae) collected in an ornamental fish farm in São Paulo State, Brazil. Thirty-three out of 40 examined fish were parasitized (82 percent prevalence) with mean intensity of 2.8 (1-20). Male specimens were 3,500µm total length and females 7,100µm total length, provided with orange-brown buccal capsule and two developed tridents. Males showed two unequal spicules, gubernaculum absent and females with vulva situated in the middle of the body. The main characteristics were the sleekly longitudinal ridges in the buccal capsule in both sexes, enlargement at the anterior end of the smaller spicule, the number of genital papillae, longer muscular and glandular portion of esophagus and round tail in female

Descreve-se Camallanus maculatus n. sp. (Nematoda: Camallanidae) em Xiphophorus maculatus (Osteichthyes: Poecilidae) capturado em uma piscicultura ornamental no estado de São Paulo. De 40 peixes examinados, 33 estavam parasitados (prevalência de 82 por cento) cuja intensidade média foi de 2,8 (1-20). Os machos apresentaram 3.500µm e as fêmeas com 7,100µm de comprimento total, providos de uma cápsula bucal laranja-castanho e dois tridentes. Observaram-se machos com espículos desiguais, gubernáculo ausente e fêmeas com vulva situada na metade do corpo. As principais características foram as estrias longitudinais lisas em cada valva da cápsula bucal em ambos os sexos, o espículo menor com alargamento na extremidade anterior, o número de papilas genitais, as porções muscular e glandular do esôfago longas e a cauda longa e arredondada na fêmea

Production of Shiga toxin by Shiga toxin-expressing Escherichia coli (STEC) in broth media: from divergence to definition.

AIMS: To determine the suitability of eight different commercial broth media for Shiga toxin (Stx) production. METHODS AND RESULTS: Shiga toxin-producing Escherichia coli (STEC) strains producing Stx1 or Stx2 were grown at 37 degrees C (250 rev min(-1)) for 24 h in brain heart infusion broth, E. coli broth, Evans medium, Luria-Bertani broth, Penassay broth, buffered-peptone water, syncase broth and trypticase soy broth. Toxin production was measured by enzyme-linked immunosorbent assay (ELISA) in polymyxin-treated cell pellets and/or supernatants of cultures, ELISA optical densities reached 1 when isolates were grown for 2-4 h in E. coli broth in the presence of antibiotic. Besides, a collection of STEC-expressing Stx strains was evaluated and the Stx production was assayed in the supernatants and in polymyxin-treated pellets of bacterial growth after 4 h of cultivation in E. coli broth in the presence of antibiotic. CONCLUSIONS: The most suitable medium for Stx production was E. coli broth when the bacterial isolates were grown for 4 h in the presence of ciprofloxacin and the Stx production is detected in the supernatant. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents the first comprehensive comparison of different broth media with regard to Stx production to establish optimal culture conditions for STEC detection in routine diagnostic laboratories.

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil

The present study describes Camallanus maculatus n. sp. (Nematoda: Camallanidae) from Xiphophorus maculatus (Osteichthyes: Poecilidae) collected in an ornamental fish farm in São Paulo State, Brazil. Thirty-three out of 40 examined fish were parasitized (82% prevalence) with mean intensity of 2.8 (1-20). Male specimens were 3,500µm total length and females 7,100µm total length, provided with orange-brown buccal capsule and two developed tridents. Males showed two unequal spicules, gubernaculum absent and females with vulva situated in the middle of the body. The main characteristics were the sleekly longitudinal ridges in the buccal capsule in both sexes, enlargement at the anterior end of the smaller spicule, the number of genital papillae, longer muscular and glandular portion of esophagus and round tail in female.

Descreve-se Camallanus maculatus n. sp. (Nematoda: Camallanidae) em Xiphophorus maculatus (Osteichthyes: Poecilidae) capturado em uma piscicultura ornamental no estado de São Paulo. De 40 peixes examinados, 33 estavam parasitados (prevalência de 82%) cuja intensidade média foi de 2,8 (1-20). Os machos apresentaram 3.500µm e as fêmeas com 7,100µm de comprimento total, providos de uma cápsula bucal laranja-castanho e dois tridentes. Observaram-se machos com espículos desiguais, gubernáculo ausente e fêmeas com vulva situada na metade do corpo. As principais características foram as estrias longitudinais lisas em cada valva da cápsula bucal em ambos os sexos, o espículo menor com alargamento na extremidade anterior, o número de papilas genitais, as porções muscular e glandular do esôfago longas e a cauda longa e arredondada na fêmea.

Neoechinorhynchus curemai (Acanthocephala: Neoechinorhynchidae) in Prochilodus lineatus (Osteichthyes: Prochilodontidae) from the Paraná River, Brazil.

This work evaluated parasitic infections by Neoechinorhynchus curemai (Acanthocephala: Neoechinorhynchidae) in Prochilodus lineatus captured between August 2000 and August 2001 in the Paraná River, Presidente Epitácio, São Paulo, Brazil. Of 87 fishes examined, 59 were infected (25 males and 34 females). High mean intensities occurred in August 2000 (45.2, range 2-204), September 2000 (28.5, range 11-73), October 2000 (59.3, range 2-250) and February 2001 (27.3, range 3-73). There was no relationship of rainfall with mean intensity and prevalence. Males were more parasitized (P<0.05) than females. This work contributes to the knowledge of helminth parasites of fish from a little studied region of the Paraná River, showing diversity in their fauna when compared to other places in the same river.

Alterations of the microcirculatory network during the clearance of epimastigote forms of Trypanosoma cruzi: an intravital microscopic study.

The distribution of epimastigote forms of Trypanosoma cruzi in the microcirculatory network and the vessel alterations were observed using an intravital microscopy technique. Immediately after intravenous inoculation of 2 x 10(6) epimastigote suspension into normal mice, parasites were seen as circulating clumps, and their retention at some sites of the endothelium of venules and capillaries was observed. Injection of 2 x 10(7) and 2 x 10(8) parasite suspensions induced, respectively, intermittent or total stasis of venules and capillaries, probably via obstruction by clumping. The mobility of epimastigotes in the clumps indicates that parasites were alive in the lumen of vessels. The retention of clumps in the capillaries, although intense, could only be observed when labeled parasites were inoculated. These results suggest that the rapid clearance of epimastigote forms of T. cruzi from the blood circulation of mice may be due to the retention of parasites to the endothelium of venules and capillaries that, in turn, may facilitate phagocytosis. This may be a mechanism by which mice are able to eliminate epimastigote forms from the circulation. These findings are consistent with our previous observations showing that epimastigotes are not lysed by complement activation but are phagocytosed and destroyed by a distinct population of blood cells.

Características das microemulsöes: uma investigaçäo de difusäo dinâmica da luz para avaliar a equivalência de duas preparaçöes similares de ciclosporina-A / Characterization of microemulsions: a dynamic light scattering investigation of Cyclosporine-A preparations

Difusäo de luz dinâmica (intensidade correlacionada à espectroscopia) é um método óptico de investigaçäo que permite obter uma medida rápida e detalhada do tamanhop médio e de toda distribuiçäo de partículascoloidais em suspensäo. Temos usado esta técnica para avaliar o tamanho médio e a multidifusäo das microemulsöes produzidas pela solubilizaçäo da preparaçöes farmacêuticas específicas baseadas na ciclosporina em um meio aquoso.(au)

Reactivity of chagasic antigal antibodies with noninfected cells treated with Trypanosoma cruzi secreted/excreted antigens.

Here, we show that antigal antibodies from Chagas' disease patients react with noninfected host cells previously treated with antigens secreted by the trypomastigote forms of Trypanosoma cruzi. With the exception of human and Old World monkey cells, which are GAL-negative, cells of all mammals express the GAL epitope (Gal alpha (1-3)Gal beta (1-4)GlcNAc-R) on their surface. Thus only the former ones develop antigal antibodies. Antigal antibodies increase during infection with T. cruzi, which expresses GAL epitopes on the surface of the infective forms. Here, we show that incubation of noninfected, GAL-negative cells with antigens shed by T. cruzi renders these cells reactive to antigal antibodies purified from chagasic sera. Neither chagasic sera depleted of antigal antibodies nor antigal antibodies purified from normal sera display reactivity with treated cells. Cell reactivity of chagasic antigal was abolished in the presence of melibiose (Gal alpha (1-6)Glc) or gal-gal (methyl 3-O-alpha-D-galactopyranosyl alpha-D-galactopyranoside). Since shedding of T. cruzi antigens can occur in vivo, these antigens may induce reactivity of chagasic antigal with noninfected human cells. The reactivity of noninfected, GAL-negative cells observed only with chagasic antigal antibodies can amplify the range of reactivity of these antibodies and consequently adds to their importance in the pathogenesis of human Chagas' disease.

Immunoblot with cerebrospinal fluid from patients with neurocysticercosis using antigen from cysticerci of Taenia solium and Taenia crassiceps.

A comparative study was conducted on membrane (M) and vesicular fluid (VF) from cysticerci of Taenia solium (Tso) obtained from naturally infected swine and the Taenia crassiceps ORF strain (Tc) maintained by experimental infection of female BALB/c mice. The study was carried out using immunoblotting to detect antibodies in cerebrospinal fluid (CSF) from patients with neurocysticercosis. No reactivity was observed in the 32 samples from a control group. Of the 23 CSF fluid samples from patients with neurocysticercosis, 22 (95.6%) were reactive in the M-Tso blot and 21 (91.3%) were reactive in the other three blots (VF-Tso, M-Tc, and VF-Tc). Immunodominant peptides in each antigen were 98-92 kD, 56-52 kD, and 72-68 kD in M-Tso; 72-68 kD, 120 kD, 155 kD, 98-94 kD, 76 kD, and 115-108 kD in VF-Tso: 72 kD, 62 kD, and 42 kD in M-Tc; and 72-68 kD and 95-92 kD in VF-Tc. The cross-reactivity observed in the immunoblots performed on CSF samples from patients with neurocysticercosis indicates that the parasites share important epitopes present at sufficient concentrations for use in immunologic tests.

Encontro de Panstrongylus megistus em ecótopo artificial: domiciliação ou mera visitação? / The finding of Panstrongylus megistus in an artificial ecotope: taking up residence or merely visiting?

No combate à doença de Chagas no Brasil, foi utilizado como primeira medida o controle químico, erradicando o Triatoma infestans, o mais importante vetor, tal combate vem favorecendo o aparecimento de vetores secundários, como Triatoma sordida and Panstrongylus megistus, espécies que podem eventualmente ser encontradas no domicílio, como os triatomíneos provenientes de Bernardino de Campos e Sete Barras por nós examinados que foram encontrados no domicílio e positivos para o T. cruzi, sugerindo que, apesar da doença de Chagas estar controlada no Estado de São Paulo, existe a necessidade de aprimorar os conhecimentos sobre o comportamento destes vetores para que mudanças nas medidas de controle sejam introduzidas.

As a first measure of Chagas' disease control in Brazil with chemical elimination of the most important vector of the disease, Triatoma infestans was removed. Attention is now being paid to Triatoma sordida and Panstrongylus megistus. That species can eventually be found inside houses, as happened with the specimens we examined from Bernardino de Campos and Sete Barras, all of them infected by Trypanosoma cruzi. These data suggest that a better knowledge about the behavior that species is needed to introduce changes in the control measures.