RESUMO
Schistosomiasis constitutes a major public health problem, with an estimated 200 million people infected worldwide. Many areas of Brazil show low endemicity of schistosomiasis, and the current standard parasitological techniques are not sufficiently sensitive to detect the low-level helminth infections common in areas of low endemicity (ALEs). This study compared the Kato-Katz (KK); Hoffman, Pons, and Janer (HH); enzyme-linked immunosorbent assay- (ELISA-) IgG and ELISA-IgM; indirect immunofluorescence technique (IFT-IgM); and qPCR techniques for schistosomiasis detection in serum and fecal samples, using the circumoval precipitin test (COPT) as reference. An epidemiological survey was conducted in a randomized sample of residents from five neighborhoods of Barra Mansa, RJ, with 610 fecal and 612 serum samples. ELISA-IgM (21.4%) showed the highest positivity and HH and KK techniques were the least sensitive (0.8%). All techniques except qPCR-serum showed high accuracy (82-95.5%), differed significantly from COPT in positivity (P < 0.05), and showed poor agreement with COPT. Medium agreement was seen with ELISA-IgG (Kappa = 0.377) and IFA (Kappa = 0.347). Parasitological techniques showed much lower positivity rates than those by other techniques. We suggest the possibility of using a combination of laboratory tools for the diagnosis of schistosomiasis in ALEs.
Assuntos
Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/estatística & dados numéricos , Doenças Endêmicas/estatística & dados numéricos , Imunoensaio/métodos , Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Imunoensaio/estatística & dados numéricos , Lactente , Masculino , Pessoa de Meia-Idade , Vigilância da População/métodos , Testes de Precipitina/métodos , Testes de Precipitina/estatística & dados numéricos , Prevalência , Reprodutibilidade dos Testes , Medição de Risco/métodos , Esquistossomose mansoni/parasitologia , Sensibilidade e Especificidade , Adulto JovemRESUMO
Schistosomiasis constitutes a major public health problem, with an estimated 200 million people infected worldwide. Many areas of Brazil show low endemicity of schistosomiasis, and the current standard parasitological techniques are not sufficiently sensitive to detect the low-level helminth infections common in areas of low endemicity (ALEs). This study compared the Kato-Katz (KK); Hoffman, Pons, and Janer (HH); enzyme-linked immunosorbent assay- (ELISA-) IgG and ELISA-IgM; indirect immunofluorescence technique (IFT-IgM); and qPCR techniques for schistosomiasis detection in serum and fecal samples, using the circumoval precipitin test (COPT) as reference. An epidemiological survey was conducted in a randomized sample of residents from five neighborhoods of Barra Mansa, RJ, with 610 fecal and 612 serum samples. ELISA-IgM (21.4%) showed the highest positivity and HH and KK techniques were the least sensitive (0.8%). All techniques except qPCR-serum showed high accuracy (8295.5%), differed significantly from COPT in positivity , and showed poor agreement with COPT. Medium agreement was seen with ELISA-IgG (Kappa = 0.377) and IFA (Kappa = 0.347). Parasitological techniques showed much lower positivity rates than those by other techniques. We suggest the possibility of using a combination of laboratory tools for the diagnosis of schistosomiasis in ALEs.
Assuntos
Esquistossomose mansoni/diagnóstico , Esquistossomose mansoni/parasitologia , Esquistossomose mansoni/epidemiologia , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Idoso , Humanos , Imunoensaio/métodos , Imunoensaio/estatística & dados numéricos , Testes de Precipitina/métodos , Criança , Pré-Escolar , Vigilância da População/métodos , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Medição de Risco/métodos , Adulto , Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/estatística & dados numéricos , Doenças Endêmicas/estatística & dados numéricos , Adulto Jovem , Lactente , Pessoa de Meia-IdadeRESUMO
Parasitological diagnostic methods for schistosomiasis lack sensitivity, especially in regions of low endemicity. The objective of this study was to determine the prevalence of Schistosoma mansoni infections by antibody detection using the indirect immunofluorescence assay (IFA-IgM) and circumoval precipitin test (COPT). Serum samples of 572 individuals were randomly selected. The IFA-IgM and COPT were used to detect anti-S. mansoni antibodies. Of the patients studied, 15.9% (N = 91) were IFA-IgM positive and 5.1% (N = 29) had COPT reactions (P < 0.001 by McNemar's test). Immunodiagnostic techniques showed higher infection prevalence than had been previously estimated. This study suggests that combined use of these diagnostic tools could be useful for the diagnosis of schistosomiasis in epidemiological studies in areas of low endemicity.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Técnica Indireta de Fluorescência para Anticorpo/métodos , Testes de Precipitina/métodos , Schistosoma mansoni/imunologia , Esquistossomose mansoni/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Brasil , Criança , Pré-Escolar , Estudos Transversais , Fezes/parasitologia , Feminino , Humanos , Imunoglobulina M/sangue , Lactente , Masculino , Pessoa de Meia-Idade , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/parasitologia , Estudos Soroepidemiológicos , Adulto JovemRESUMO
New data on the feeding patterns of Haemagogus (Haemagogus) janthinomys Dyar from different geographical regions of Brazil, by using the precipitin test as the bloodmeal-identifying tool, are presented. The following antisera were used: bird, dog, human, rodent, cattle, horse, and opossum. The origins of 287 bloodmeals were identified, whereas 33 specimens were negative to the antiserums tested. Among the reactive specimens, 174 (60.6%) fed on only one food source, of which 35.1% originated from birds, 19.5% from rodents, 12.6% from humans, 10.3% from cattle, 10.3% from opossums, 7.5% from dogs, and 4.6% from horses. One hundred six (37.0%) mosquitoes fed on two sources, of which the most common combinations were bird + rodent (16.0%), bird + human (10.4%), and horse + human (9.4%). Seven (2.4%) mosquitoes fed on three different hosts. Our results suggest that Hg. janthinomys is more eclectic and opportunist than previously known in relation to its hosts and that such patterns are probably highly adaptive to a temporally and spatially variable environment.
Assuntos
Culicidae/fisiologia , Insetos Vetores/fisiologia , Animais , Aves , Brasil , Bovinos , Transmissão de Doença Infecciosa , Cães , Comportamento Alimentar , Feminino , Cavalos , Humanos , Gambás , Testes de Precipitina/métodos , RoedoresRESUMO
Bloodmeals taken by insects constitute an important parameter for clarifying aspects of the transmission of zoonoses, including leishmaniases. Immunological assays can be used to investigate the attraction of vectors to animals, which may be hosts of these parasitoses. The objective of this study was to standardize a sandwich enzyme-linked immunosorbent assay and titer samples with different time periods of digestion, in laboratory-bred Lutzomyia longipalpis fed on rats. In the light of the high sensitivity that the biotin-avidin method permits, the technique provided at least ninety repeat tests for each sample and identified recent bloodmeals taken by these insects. Bloodmeals were detectable up to 12 and 24 h after blood ingestion, and a significant difference between these titers was observed.
Assuntos
Avidina , Biotina , Sangue , Ensaio de Imunoadsorção Enzimática/normas , Insetos Vetores , Psychodidae , Animais , Feminino , Masculino , Testes de Precipitina/métodos , Ratos , Sensibilidade e Especificidade , Fatores de TempoRESUMO
Actin cytoskeleton disruption in host cells has been demonstrated for PTPases from pathogenic microorganisms. In this work, we analysed whether the secreted acid phosphatase from Entamoeba histolytica has phosphotyrosine phosphatase activity and the possibility that this activity may participate in damaging host cells. The secreted acid phosphatase of E. histolytica, which catalyses p-nitrophenyl phosphate hydrolysis at acid pH values, was found to have phosphotyrosine phosphatase activity. The enzymatic properties of phosphotyrosine phosphatase and acid phosphatase were virtually identical and included: Km values of 10 x 10(-4) M, no requirement for divalent cations, and sensitivity to molybdate, vanadate, and tungstate. The phosphotyrosyl phosphatase activity caused significant levels of cell rounding and detachment correlating with disruption of the actin stress fibres in HeLa cells. Thus, our data suggest that secreted phosphotyrosine phosphatase could play a cytotoxic role during amoebic infection.
Assuntos
Entamoeba histolytica/patogenicidade , Células HeLa/parasitologia , Interações Hospedeiro-Parasita , Proteínas Tirosina Fosfatases/isolamento & purificação , Proteínas de Protozoários/isolamento & purificação , Citoesqueleto de Actina/ultraestrutura , Animais , Anticorpos Monoclonais/metabolismo , Morte Celular , Entamoeba histolytica/enzimologia , Células HeLa/ultraestrutura , Humanos , Placenta/enzimologia , Testes de Precipitina/métodos , Proteínas Tirosina Fosfatases/imunologia , Proteínas Tirosina Fosfatases/metabolismo , Proteínas de Protozoários/metabolismoRESUMO
The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the pathogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding.
Assuntos
Aedes/fisiologia , Sangue , Ensaio de Imunoadsorção Enzimática/métodos , Testes de Precipitina/métodos , Animais , Gatos , Criopreservação/métodos , Cães , Ingestão de Alimentos , Comportamento Alimentar , Feminino , Humanos , Sensibilidade e Especificidade , Fatores de TempoRESUMO
The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the patogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding
Assuntos
Humanos , Animais , Feminino , Gatos , Cães , Aedes/fisiologia , Sangue , Ingestão de Alimentos , Ensaio de Imunoadsorção Enzimática/métodos , Testes de Precipitina/métodos , Criopreservação/métodos , Comportamento Alimentar , Sensibilidade e Especificidade , Fatores de TempoRESUMO
An immunoprecipitation technique using biotin-labeled proteins of Taenia solium was developed to identify antigens recognized by immunoglobulins from patients with neurocysticercosis. Six major polypeptides of 100, 70, 50, 42, 35, and 24 kDa were recognized by cerebrospinal fluid from most serologically positive patients. All polypeptides except the 70- and 35-kDa antigens were retained on a lentil-lectin chromatography column and were recognized by lentil lectin in an overlay assay. The 70- and 35-kDa antigens were not labeled with biotin hydrazide, indicating that saccharide residues are not present in these two polypeptides. Furthermore, the 70- and 35-kDa antigens were recognized by antibodies of more than 86% of patients serologically positive for neurocysticercosis as opposed to none of the patients afflicted with other neuropathologies of the central nervous system. This finding indicates that immunodiagnosis of neurocysticercosis can be carried out with antigens different from those used in the standard enzyme-linked immunoelectrotransfer assay.
Assuntos
Anticorpos Anti-Helmínticos/imunologia , Antígenos de Helmintos/imunologia , Neurocisticercose/imunologia , Peptídeos/imunologia , Taenia/imunologia , Animais , Anticorpos Anti-Helmínticos/líquido cefalorraquidiano , Antígenos de Helmintos/análise , Ensaio de Imunoadsorção Enzimática/métodos , Glicosilação , Humanos , Neurocisticercose/líquido cefalorraquidiano , Neurocisticercose/diagnóstico , Peptídeos/análise , Testes de Precipitina/métodosRESUMO
An enzyme-linked immunosorbent assay (ELISA) for trichinosis using a Melcher's antigen was developed for the detection of IgG antibodies in 41 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. ELISA- IgG was compared with a precipitin test (PT), a bentonite floculation test (BFT) and an indirect hemagglutination test (IHAT). The cut-off value was determined using serum samples from 67 apparently healthy persons employing two serum dilutions (1:100 and 1:500) with three standard deviations (SD). The sensitivity of ELISA- IgG was 97.6% and 95.2% using serum dilutions of 1:100 and 1:500 respectively, whereas the values for the other tests were: PT (92.7%), BFT (63.4%) and IHAT(85.4%). According to MacNemar test, ELISA-IgG did not present statistical significance (p > 0.05) compared with PT and IHAT, whereas all of them were different compared with BHT (p > 0.01). In order to find out the specificity of ELISA-IgG, additional 124 serum samples from individuals with other parasitoses, such as cysticercosis (31), fascioliasis (17), hydatidosis (51) and toxocariasis (25) were also tested. ELISA-IgG presented a specificity of 99.5% with both serum dilutions. The positive predictive values were 97.6 and 97.5%, whereas the negative one were 99.5 and 99.0% for 1:100 and 1:500 serum dilutions respectively. The use of ELISA-IgG and Melcher's antigen in the diagnosis of human trichinosis is discussed.