Intestinal parasitism in San Cayetano, Corrientes, Argentina.

An epidemiologic study was conducted in San Cayetano, a village in the province of Corrientes, Argentina, to determine the prevalence of intestinal parasitoses in children. Eighty-eight households were randomly selected. Stool samples were collected from 207 children (72% of the school-age population and 12% of the total village population) over a period of six consecutive days, and were subjected to microscopic examination. Of the samples examined, 170 (83%) contained one or more parasites, of which the most frequently found was Blastocystis hominis (in 43% of the samples). Other parasites and commensals detected included Giardia lamblia (29%), hookworms (27%), Entamoeba coli (27%), Enterobius vermicularis (4%), Strongyloides stercoralis (2%), and Ascaris lumbricoides, Trichuris trichiura, Taenia saginata, Isospora belli, Iodamoeba bütschlii, and Balantidium coli (each 0.5%). The high observed prevalence of intestinal parasitoses indicates active parasite transmission in San Cayetano as a result of poor environmental hygiene-ascribable largely to a lack of public water supply, sewerage, and waste removal services.

Trypanosoma cruzi: a carbohydrate epitope defined by a monoclonal antibody as a possible marker of the acute phase of human Chagas' disease.

An IgM monoclonal antibody (MAb) against a carbohydrate epitope present in Trypanosoma cruzi trypomastigote excretory-secretory antigens and expressed by different developmental stages of the parasite (epimastigote, trypomastigote and intracellular amastigote) was linked to a solid phase matrix and used as an antigen-capture antibody. Human serum complexes containing the epitope were then detected by using specific secondary antibodies against human immunoglobulin isotypes. Results of detection of IgM, IgG, and IgA serum complexes (SC) containing a T. cruzi polypeptide epitope showed that SC could be detected in 69% of the 13 Chagasic acute phase sera studied with IgG, in 84% with IgM, and in 75% with IgA. Only 16% (IgG-SC), 8% (IgM-SC), and 10% (IgA-SC) of chronic sera from 50 patients were positive. No patients with toxoplasmosis or rheumatoid factor were positive. Of the 11 leishmaniasis sera studied, four had IgG-SC, two had IgA-SC, and five had IgM-SC. Of the eight Yanomamo Indians infected by Onchocerca volvulus, three were found to have IgG-SC, two had IgM-SC, and two had IgA-SC. Thirteen sera from healthy individuals living in an endemic area were also studied. One subject had IgG IgM and IgA-SC. The results presented in this study show for the first time, the specific detection of IgM, IgG, and IgA immune complexes using a MAb against T. cruzi. The presence of the epitope in association with IgM antibodies in sera from patients with the acute phase of the disease suggests that this antigen(s) carrying the epitope that reacts with the MAb could be a marker(s) of active infection. In addition, the specificity of the serum complex capture assay allowed the detection of Chagas' disease in two different endemic areas (Argentina and Venezuela).

Trypanosoma cruzi: circulating polysaccharide factors excreted in vitro and in vivo.

An antigen factor (EF), thermostable and soluble in trichloroacetic acid was detected in the supernatant fluid of epimastigote cultures of Trypanosoma cruzi and in the sera of patients with acute Chagas disease. An hyperimmune antiserum to this antigenic factor was obtained in rabbits. The EF was revealed on the fibroblast surface membranes of rats infected with trypomastigotes, using the indirect immunofluorescence technique. The presence of EF in the sera of patients with acute Chagas disease as well as in the supernatant of epimastigotes culture at logarithmic phase, leads to its association with a process of parasite proliferation. Being EF a component of the parasite, its origin both in vitro and in vivo could be the result of an excretion-secretion of parasite or simply a result of the parasite's death. It can be postulated that the same as in other protozoic infection, EF could be used by T. cruzi in the process of cell penetration.

Trypanosoma cruzi: circulating polysaccharide factors excreted in vitro and in vivo

Se detectó un factor antigénico, temoestable y soluble en ácido tricloroacético (TCA) en el sobrenadante de cultivo de epimatigotes de Trypanosoma cruzi en fase logarítmica y en los sueros de pacientes con enfermedad de Chagas aguda. Este antígeno fue revelado en la mambrana de superficie de fibroblastos de ratas cuando fueron infectados con trypomastigotes, utilizando la técnica de inmunofluorescencia indirecta. El sobrenadante de cultivo de epimastigotes en medio GLSH libre de células a 28-C fue acidificado a pH5, calentado a ebullición 30 min y luego precipitado con TCA, centrifugado y el sobrenadante tratado con éter de petróleo. La solución extraída fue dializada, concentrada, liofilizada y purificada por cromatografía de afinidad. El eluido fue liofilizado y este material fue denominado factor antígeno excretado (EF). Un antisuero hiperinmune contra estos factores antígenos fue obtenido en conejos. El 76,6% de los sueros correspondientes a pacientes con Chagas agudo demostraron poseer el EF por técnica de inmunodifusión doble (Tabla 1). Monocapas de fibroblastos de ratas infectados previamente con 3 ml de trypomastigotes en una concentración de 5 x 10**6 células/ml sometidas a una inmunofluorescencia indirecta con el antisuero hiperinmune demostraron la presencia del EF en las membranas celulares de fibroblastos infectados y no infectados..

Trypanosoma cruzi: circulating polysaccharide factors excreted in vitro and in vivo.

An antigen factor (EF), thermostable and soluble in trichloroacetic acid was detected in the supernatant fluid of epimastigote cultures of Trypanosoma cruzi and in the sera of patients with acute Chagas disease. An hyperimmune antiserum to this antigenic factor was obtained in rabbits. The EF was revealed on the fibroblast surface membranes of rats infected with trypomastigotes, using the indirect immunofluorescence technique. The presence of EF in the sera of patients with acute Chagas disease as well as in the supernatant of epimastigotes culture at logarithmic phase, leads to its association with a process of parasite proliferation. Being EF a component of the parasite, its origin both in vitro and in vivo could be the result of an excretion-secretion of parasite or simply a result of the parasites death. It can be postulated that the same as in other protozoic infection, EF could be used by T. cruzi in the process of cell penetration.

Trypanosoma cruzi: circulating polysaccharide factors excreted in vitro and in vivo

Se detectó un factor antigénico, temoestable y soluble en ácido tricloroacético (TCA) en el sobrenadante de cultivo de epimatigotes de Trypanosoma cruzi en fase logarítmica y en los sueros de pacientes con enfermedad de Chagas aguda. Este antígeno fue revelado en la mambrana de superficie de fibroblastos de ratas cuando fueron infectados con trypomastigotes, utilizando la técnica de inmunofluorescencia indirecta. El sobrenadante de cultivo de epimastigotes en medio GLSH libre de células a 28-C fue acidificado a pH5, calentado a ebullición 30 min y luego precipitado con TCA, centrifugado y el sobrenadante tratado con éter de petróleo. La solución extraída fue dializada, concentrada, liofilizada y purificada por cromatografía de afinidad. El eluido fue liofilizado y este material fue denominado factor antígeno excretado (EF). Un antisuero hiperinmune contra estos factores antígenos fue obtenido en conejos. El 76,6% de los sueros correspondientes a pacientes con Chagas agudo demostraron poseer el EF por técnica de inmunodifusión doble (Tabla 1). Monocapas de fibroblastos de ratas infectados previamente con 3 ml de trypomastigotes en una concentración de 5 x 10**6 células/ml sometidas a una inmunofluorescencia indirecta con el antisuero hiperinmune demostraron la presencia del EF en las membranas celulares de fibroblastos infectados y no infectados..