RESUMO
Complement fixation (CF), indirect immunofluorescence (IFAT), latex agglutination (LA) and the enzyme-linked immunosorbent assay (ELISA) were applied to assess the diagnostic value of antibody determination in Brazilian patients with acute or chronic Chagas' disease. Patients with various forms of leishmaniasis and healthy individuals from the endemic region were used as specificity controls. Whereas LA, IFAT and ELISA identified 81% of acutely ill patients, CF had no diagnostic potential in this phase of the disease. In later stages CF showed a sensitivity of 69% as compared to 100% for LA, IFAT and ELISA, irrespective whether patients presented clinically as chronic asymptomatic or chronic symptomatic cases. Cross-reactivity with anti-leishmania antibodies was observed in 23%, 38% and 77% of serum samples in LA, ELISA and IFAT, respectively, but not in CF.
Assuntos
Doença de Chagas/diagnóstico , Testes Sorológicos/métodos , Doença Aguda , Adolescente , Adulto , Brasil , Criança , Doença Crônica , Testes de Fixação de Complemento , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Humanos , Testes de Fixação do Látex , Masculino , Sensibilidade e EspecificidadeRESUMO
Parasitic infections and malnutrition coexist in many tropical and subtropical areas. Studies of Leishmania donovani and of experimentally infected Syrian hamsters have provided important insights into the complex interrelationships between malnutrition and this parasitic disease. Malnutrition, which adversely affects cell-mediated immunity, is associated with the development of visceral leishmaniasis (kala-azar) in children living in endemic areas. In turn, L. donovani can cause wasting as well as hepatosplenomegaly, fever, and anemia. Syrian hamsters infected with L. donovani develop a disease that is comparable to that of humans with kala-azar. Weight loss in infected hamsters is associated with splenic macrophage secretion of potentially catabolic cytokines as measured by the D10.G4.1 assay for interleukin-1 and the L929 cytotoxicity assay for tumor necrosis factor/cachectin. Although decreased food intake contributes to wasting in infected hamsters, studies of skeletal muscle function indicate that it is not the sole factor. Leishmania donovani-infected hamsters have also been used to study drugs with the potential to prevent or reverse cachexia.
Assuntos
Caquexia/fisiopatologia , Leishmaniose Visceral/fisiopatologia , Tecido Adiposo , Animais , Brasil , Caquexia/imunologia , Criança , Transtornos da Nutrição Infantil/imunologia , Transtornos da Nutrição Infantil/fisiopatologia , Pré-Escolar , Cricetinae , Modelos Animais de Doenças , Humanos , Interleucina-1/biossíntese , Leishmaniose Visceral/imunologia , Mesocricetus , Distúrbios Nutricionais/imunologia , Distúrbios Nutricionais/fisiopatologia , Desnutrição Proteico-Calórica/imunologia , Desnutrição Proteico-Calórica/fisiopatologia , Linfócitos T/imunologia , Fator de Necrose Tumoral alfa/fisiologiaRESUMO
From October until July 1991, CDC miniature light traps were set up and man and animal-landing and biting catches were made in 100 different catching zones, in different habitats, throughout the ACL focus of the Serra de Baturité. Female Lutzomyia whitmani and Lu. wellcomei appeared to be highly anthropophilic and were the most prevalent species in man-landing catches in peridomestic sites. Most Lu. migonei were attracted to animals, especially mules. Seasonal fluctuations and habitat preference were noted for the principal populations present.
Assuntos
Insetos Vetores , Leishmania , Leishmaniose Cutânea/transmissão , Psychodidae , Animais , Brasil/epidemiologia , Comportamento Alimentar , Feminino , Humanos , Incidência , Insetos Vetores/microbiologia , Insetos Vetores/fisiologia , Leishmaniose Cutânea/epidemiologia , Masculino , Perissodáctilos , Psychodidae/microbiologia , Psychodidae/fisiologia , Estações do Ano , Especificidade da EspécieRESUMO
American visceral leishmaniasis (AVL) is an important disease among children of northeast Brazil. In order to characterize antibody responses during AVL, sera of hospitalized patients were analyzed by ELISA and Western blot using a Leishmania chagasi antigen preparation. The ELISA was positive (absorbance greater than or equal to 0.196) at a serum dilution of 1:1024 in all patients at presentation, and fell to ward control levels over the following year. Only one of 72 control subjects tested positive, and that donor had a sibling with AVL. Immunoblots of the patients' sera recognized multiple bands, the most frequent of which were at approximately 116 kDa, 70 kDa, and 26 kDa. Less frequently observed were bands at approximately 93 kDa, 74 kDa, 62 kDa, 46 kDa and 32 kDa. The ELISA responses and patterns of banding were distinctive for AVL, and could be used to differentiate patients with AVL from those with Chagas' disease or cutaneous leishmaniasis. Sera from six AVL patients followed for up to six weeks after treatment identified no new bands. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of surface iodinated parasite proteins showed one major band and four minor bands, whereas SDS-PAGE of biotinylated parasite proteins revealed a banding pattern similar to those of patient sera. AVL appears to produce characteristic immunoblot patterns which can be used along with a sensitive screening ELISA to diagnose AVL.
Assuntos
Anticorpos Antiprotozoários/análise , Western Blotting , Ensaio de Imunoadsorção Enzimática , Leishmania donovani/imunologia , Leishmaniose Visceral/imunologia , Animais , Formação de Anticorpos , HumanosRESUMO
Little is known about the interrelationship between undernutrition and parasitic infections in areas of the world where both are prevalent. The associations between undernutrition and visceral leishmaniasis, an important protozoal disease, were assessed in a study of residents of an area in Brazil with endemic leishmaniasis. Mid-arm anthropometry was used to assess fat and muscle area. Children with visceral leishmaniasis came from large families (9.6 +/- 1.1 members vs. 6.8 +/- 0.7 members in neighborhood control families), and patient housemates had fat areas that were 78% (P less than .05) those of age- and sex-matched neighborhood controls. The children with visceral leishmaniasis who were studied four months or less after diagnosis had fat areas that were 66% (P less than .05) those of age- and sex-matched household controls or 41% (P less than .01) those of neighborhood controls and muscle areas that were 81% (P less than .025) those of household controls or 75% (P less than .05) those of of neighborhood controls. It is hypothesized, on the basis of these data and other findings, that undernutrition is associated with the development of clinically apparent visceral leishmaniasis and that the disease itself has a profound effect on nutritional status, resulting in loss of both muscle and fat, effects that possibly are mediated by interleukin-1 and/or other factors produced by Leishmania donovani-infected macrophages.
Assuntos
Leishmaniose Visceral/etiologia , Modelos Biológicos , Distúrbios Nutricionais/complicações , Tecido Adiposo/patologia , Brasil , Pré-Escolar , Feminino , Humanos , Lactente , Leishmaniose Visceral/patologia , Masculino , Músculos/patologia , Distúrbios Nutricionais/patologiaRESUMO
Visceral leishmaniasis (kala-azar) is an important cause of morbidity and mortality in widely scattered areas of the world. To better characterize the South American form of the disease, the clinical and laboratory manifestations of 29 patients admitted to hospital (18 male and 11 female patients, mean age 4.9 years), were assessed in an endemic area in northeastern Brazil. Fever, weight loss, pronounced splenomegaly, hepatomegaly, anemia, thrombocytopenia, relative neutropenia, hypoalbuminemia and hypergammaglobulinemia were found in the majority of patients. Symptoms were often present for two or more months before diagnosis. Secondary infections complicated many cases; there were ten cases of pneumonia and half of the patients had one or more intestinal parasites. The average length of hospital stay was 27 days; all patients were treated with meglumine antimoniate (Glucantime). The mortality rate was 3%. American visceral leishmaniasis remains an important disease among children living in endemic areas.
Assuntos
Leishmaniose Visceral , Brasil , Pré-Escolar , Feminino , Humanos , Leishmaniose Visceral/diagnóstico , MasculinoRESUMO
It has been hypothesized that the Leishmania use a system of camouflage or mimicry of human ABO blood group antigens to evade host defense mechanisms. In order to test this hypothesis, the distribution of ABO blood groups among healthy control donors and among patients with visceral leishmaniasis in northeastern Brazil was compared. No significant differences were found between patients with American visceral leishmaniasis and controls, indicating that ABO blood group type is not an important determinant in the development of clinically apparent visceral leishmaniasis in that area. The findings raise doubt about the validity of the original hypothesis.