[Incidence of rotavirus in intensive-production poultry farms]. / Incidencia de los rotavirus en establecimientos avícolas de producción intensiva.

Rotavirus are the major etiological agent of acute gastroenteritis in various species of mammals and birds. This study was aimed to explore the frequency of rotavirus in flocks of commercial laying hens and industrial broiler chicken. Feces and caecal content were sampled from 589 birds belonging to 17 farms located in the neighbourhood of Lujan National University. RNA patterns were explored by polyacrylamide gel electrophoresis. Viral particles were found with moderate frequency throughout the period of study: 7.06% in 1987; 7.45% in 1988; 12.57% in 1989. This finding demonstrates the permanence of rotavirus infection in the farm under study and emphasizes the importance of routine rotavirus screening in industrial poultry farms.

Incidencia de los rotavirus en establecimientos avícolas de producción intensiva. / [Incidence of rotavirus in intensive-production poultry farms]

Rotavirus are the major etiological agent of acute gastroenteritis in various species of mammals and birds. This study was aimed to explore the frequency of rotavirus in flocks of commercial laying hens and industrial broiler chicken. Feces and caecal content were sampled from 589 birds belonging to 17 farms located in the neighbourhood of Lujan National University. RNA patterns were explored by polyacrylamide gel electrophoresis. Viral particles were found with moderate frequency throughout the period of study: 7.06

in 1987; 7.45

in 1988; 12.57

in 1989. This finding demonstrates the permanence of rotavirus infection in the farm under study and emphasizes the importance of routine rotavirus screening in industrial poultry farms.

Further evaluation of an indirect enzyme-linked immunosorbent assay for the diagnosis of bovine tuberculosis.

The sensitivity and specificity of an ELISA for the detection of bovine IgG anti-Mycobacterium bovis antibodies were 73.6% and 94.1%, respectively, as determined in 53 bacteriologically confirmed tuberculous cattle and 101 healthy cattle from a tuberculosis-free area. In addition, the results of ELISA and tuberculin tests in 149 cattle were compared with those of subsequent necropsy studies. Both tests failed to detect 2 animals with tuberculous lesions and positive culture; 3/12 cattle with M. bovis isolation and no lesions, and 2/7 with atypical mycobacterial infection reacted to tuberculin, but none had antibodies; in 128 cattle with neither lesions nor mycobacterial isolation, 6 were tuberculin reactors and 7 others had antibodies. Negative results were obtained by ELISA in 21/22 paratuberculous cattle. Antibodies were not detected in 88.9% to 96.4% of 697 cattle from two tuberculin negative herds of an endemic area. In a herd with proved M. bovis infection, distribution of seropositive animals in tuberculin and non-tuberculin reactors was similar. Antibody responses to cutaneous tuberculin stimuli were observed in 4 experimentally infected cattle, but only in 2/10 healthy controls after repeated PPD stimuli. Nine controls which had either received a single tuberculin dose or none showed no increase in antibody levels. The low sensitivity of this ELISA limits its usefulness as a diagnostic tool for bovine tuberculosis eradication campaigns. However, it could be helpful in epidemiological surveillance if its efficiency to identify infected herds is demonstrated.

Estudio comparativo de cuatro métodos de aislamiento de salmonelas de aguas superficiales / Comparative study of 4 methods for isolating Salmonella from surface waters

El presente trabajo es la primera etapa de un proyecto destinado a determinar la presencia de serovariedades de Salmonella en aguas del Río Lujáan, que recorre la zona urbana de la ciudad homónima, en la provincia de Buenos Aires. Consiste en realizar un estudio comparativo de cuatro métodos de detección de salmonelas a partir de 200 muestras de dicho río: caldos tetrationato-verde brilhante; manitol y selenito; Rappaport 25 y Rappaport-Vassiliadis modificado, con y sin preenriquecimiento de las muestras en agua peptonada fosfatada. Para las tomas, se aplicó la técnica del pliego de gasa sumergido, en tres puntos de muestreo: uno en la planta urbana, otro a 2 km aguas arriba de la misma y el último a 2 km aguas abajo de la ciudad. La mejor combinación de medios de enriquecimiento y de aislamiento estuvo dada por caldo Rappaport-Vassiliadis modificado y agar verde brilhante con 0,25% de desoxicolato de sodio, luego de preenriquecer las muestras en agua peptonada fosfatada. Se aisló Salmonella en el 46% de las muestras examinadas, identificándose 16 serovariedades. Entre otras, se hallaron: S. Typhimurium, S. Enteritidis, S. Infantis, S. Mbandaka, S. Israel y S. Sub-especie IV 18 z36 : Z38:-

Estudio comparativo de cuatro métodos de aislamiento de salmonelas de aguas superficiales / Comparative study of 4 methods for isolating Salmonella from surface waters

El presente trabajo es la primera etapa de un proyecto destinado a determinar la presencia de serovariedades de Salmonella en aguas del Río Lujáan, que recorre la zona urbana de la ciudad homónima, en la provincia de Buenos Aires. Consiste en realizar un estudio comparativo de cuatro métodos de detección de salmonelas a partir de 200 muestras de dicho río: caldos tetrationato-verde brilhante; manitol y selenito; Rappaport 25 y Rappaport-Vassiliadis modificado, con y sin preenriquecimiento de las muestras en agua peptonada fosfatada. Para las tomas, se aplicó la técnica del pliego de gasa sumergido, en tres puntos de muestreo: uno en la planta urbana, otro a 2 km aguas arriba de la misma y el último a 2 km aguas abajo de la ciudad. La mejor combinación de medios de enriquecimiento y de aislamiento estuvo dada por caldo Rappaport-Vassiliadis modificado y agar verde brilhante con 0,25% de desoxicolato de sodio, luego de preenriquecer las muestras en agua peptonada fosfatada. Se aisló Salmonella en el 46% de las muestras examinadas, identificándose 16 serovariedades. Entre otras, se hallaron: S. Typhimurium, S. Enteritidis, S. Infantis, S. Mbandaka, S. Israel y S. Sub-especie IV 18 z36 : Z38:- (AU)

[Comparative study of 4 methods for isolating Salmonella from surface waters]. / Estudio comparativo de cuatro métodos de aislamiento de salmonelas de aguas superficiales.

The study presented here is the first stage of a project designed to determine the presence of Salmonella serotypes in Lujan river waters, which flow beside the urban area of the homonymous city, in the province of Buenos Aires. It consisted in a comparative study of four methods for Salmonellae detection in 200 samples: Tetrathionate-brilliant green; mannitol-selenite; Rappaport 25 and modified Rappaport-Vassiliadis broth, each of them with and without pre-enrichment in buffered peptone water. The submerged gauze technique was applied to the sampling in three different spots of the river: at the town center, two km water above, and two down-stream from the city. Best results were obtained when modified Rappaport-Vassiliadis enrichment broth and brilliant green agar with 0.25% of sodium deoxycholate were used, after pre-enrichment of the samples in buffered peptone water. Salmonella were isolated from 46% of the samples studied, and 16 serotypes were identified: S. Typhimurium, S. Enteritidis, S. Infantis, S. Mbandaka, S. Israel and S. Subspecies IV 18 z36: z38:-, among them.

Estudio comparativo de cuatro métodos de aislamiento de salmonelas de aguas superficiales. / [Comparative study of 4 methods for isolating Salmonella from surface waters]

The study presented here is the first stage of a project designed to determine the presence of Salmonella serotypes in Lujan river waters, which flow beside the urban area of the homonymous city, in the province of Buenos Aires. It consisted in a comparative study of four methods for Salmonellae detection in 200 samples: Tetrathionate-brilliant green; mannitol-selenite; Rappaport 25 and modified Rappaport-Vassiliadis broth, each of them with and without pre-enrichment in buffered peptone water. The submerged gauze technique was applied to the sampling in three different spots of the river: at the town center, two km water above, and two down-stream from the city. Best results were obtained when modified Rappaport-Vassiliadis enrichment broth and brilliant green agar with 0.25

of sodium deoxycholate were used, after pre-enrichment of the samples in buffered peptone water. Salmonella were isolated from 46

of the samples studied, and 16 serotypes were identified: S. Typhimurium, S. Enteritidis, S. Infantis, S. Mbandaka, S. Israel and S. Subspecies IV 18 z36: z38:-, among them.

[Evaluation of four antigens for the detection of anti-Mycobacterium bovis antibodies by enzyme immunoassay]. / Evaluación de cuatro antígenos para la detección de anticuerpos anti-Mycobacterium bovis por enzimoinmunoensayo.

An enzyme-linked immunosorbent assay (ELISA) for the diagnosis of bovine tuberculosis through the detection of specific seric antibodies has recently been developed in our laboratory. In order to assess its reproducibility and select the most adequate antigen, four bovine PPDs from different sources were evaluated in parallel: PPD M. bovis strain AN5, CEPANZO standard (CPZ), PPD M. bovis strain AN5, European Economic Community standard (EEC), PPD M. bovis strain AN5, prepared from non heated bacilli, killed by phenol (P) and PPD. M. bovis BCG strain prepared at the Pasteur Institute, Paris (BCG). Sera from 22 healthy cattle from tuberculosis free area and 20 bacteriologically confirmed tuberculous animals were employed in simultaneous assays. Antibody mean and standard deviations from healthy cattle expressed as optical density (OD) values were 45 +/- 22 when CPZ was used as antigen, 24 +/- 10 with EEC, 103 +/- 56 with P and 56 +/- 20 with BCG. Mean O.D. from tuberculous cattle were 588 +/- 158, 510 +/- 234, 782 +/- 138 and 441 +/- 189 with antigens CPZ, EEC, P and BCG respectively. A close correlation was observed when results obtained with EEC and P were compared with that of CPZ (r: 0.97 and 0.94 respectively). A lower specificity was achieved when BCG was used as antigen being also lower its correlation with the results obtained with CPZ (r: 0.87). It is concluded that our ELISA would achieve similar sensitivity and specificity if CPZ, EEC and P were used as antigens. On the other hand, BCG would not be suitable for this assay.

Evaluación de cuatro antígenos para la detección de anticuerpos anti-Mycobacterium bovis por enzimoinmunoensayo. / [Evaluation of four antigens for the detection of anti-Mycobacterium bovis antibodies by enzyme immunoassay]

An enzyme-linked immunosorbent assay (ELISA) for the diagnosis of bovine tuberculosis through the detection of specific seric antibodies has recently been developed in our laboratory. In order to assess its reproducibility and select the most adequate antigen, four bovine PPDs from different sources were evaluated in parallel: PPD M. bovis strain AN5, CEPANZO standard (CPZ), PPD M. bovis strain AN5, European Economic Community standard (EEC), PPD M. bovis strain AN5, prepared from non heated bacilli, killed by phenol (P) and PPD. M. bovis BCG strain prepared at the Pasteur Institute, Paris (BCG). Sera from 22 healthy cattle from tuberculosis free area and 20 bacteriologically confirmed tuberculous animals were employed in simultaneous assays. Antibody mean and standard deviations from healthy cattle expressed as optical density (OD) values were 45 +/- 22 when CPZ was used as antigen, 24 +/- 10 with EEC, 103 +/- 56 with P and 56 +/- 20 with BCG. Mean O.D. from tuberculous cattle were 588 +/- 158, 510 +/- 234, 782 +/- 138 and 441 +/- 189 with antigens CPZ, EEC, P and BCG respectively. A close correlation was observed when results obtained with EEC and P were compared with that of CPZ (r: 0.97 and 0.94 respectively). A lower specificity was achieved when BCG was used as antigen being also lower its correlation with the results obtained with CPZ (r: 0.87). It is concluded that our ELISA would achieve similar sensitivity and specificity if CPZ, EEC and P were used as antigens. On the other hand, BCG would not be suitable for this assay.

In vitro effect of Mycobacterium leprae suspensions on the polymorphonuclear neutrophils function of hanseniasis patients to Candida albicans and Candida pseudotropicalis.

The in vitro effect of Mycobacterium leprae suspensions on the PMN ability to phagocytizing and killing Candida albicans and Candida pseudotropicalis was studied in forty-five patients of Hansen's disease and in fifteen healthy controls. Our results show no significative differences between the different studied groups, both for the phagocytosis and for the lysis of yeasts. There was no significant changes in the mean values of these functions after previous or simultaneously incubation with Mycobacterium leprae suspensions. Those observations confirmed that there are not alterations in the enzymatic battery of PMN in Hansen's disease patients and that the Mycobacterium leprae presence does not exert stimulating effect on this in vitro model.

Cell mediated immune response of Bufo arenarum and Leptodactylus ocellatus (Amphibia, Anura) to mycobacterial antigens.

The lymphocyte transformation test was applied to the study of cell mediated immune (CMI) response in vitro to mycobacterial antigens in Bufo arenarum and Leptodactylus ocellatus previously inoculated with a suspension of Mycobacterium tuberculosis. The stimulated samples of blood both in B. arenarum and L. ocellatus showed a significant increase in the percent of blastic dedifferentiation (almost 100% with respect to controls) suggesting the presence of a positive CMI response to PPD. The differences were observed on the fifth day of incubation and lasted until the seventh day.

[Change in cell-mediated immunity to Mycobacterium leprae and Mycobacterium marinum in Hansen's disease patients]. / Alteración de la inmunidad mediada for células frente a Mycobacterium leprae y Mycobacterium marinum en pacientes hansenianos.

The cell mediated immunity (CMI) to protein purified derivates of Mycobacterium leprae, Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium marinum was studied. Leukocyte Migration Inhibition (LMI) and Delayed Hypersensitivity skin reactions to these antigens were examined in 44 hanseniasis patients (20 quiescent Virchowians, 13 reactional Virchowians and 11 tuberculoid patients) and 15 healthy subjects. An impairment in LMI and Delayed Hypersensitivity tests to M. leprae and M. marinum was observed in Virchowians patients both quiescent and reactional. The CMI response to all mycobacterial antigens was increased in tuberculoid patients and was observed a poor response to M. leprae and M. marinum in healthy controls. Our results show a high correlation between the CMI response to M. leprae and to M. marinum (r = + 0,8). This close relationship between both antigens may express cross-reactivity.

Alteracion de la inmunidad mediada por celulas frente a Mycobacterium leprae y Mycobacterium marinum en pacientes hansenianos. / Change of the cell-mediated immunity to Mycobacterium leprae and Mycobacterium marinum in Hansen's disease patients

Se estudio la inmunidad mediada por celulas (IMC) frente a derivados proteicos purificados de Mycobacterium leprae, Mycobacterium tuberculosis, Mycobacterium avium y Mycobacterium marinum. Se efectuaron tests cutaneos de hipersensibilidad retardada e inhibicion de la migracion de leucocitos in vitro en 44 pacientes hansenianos (20 virchowianos quiescentes, 13 virchowianos reaccionales y 11 tuberculoides) y en 15 testigos sanos. Se observo una alteracion de la inhibicion de la migracion de leucocitos y de la hipersensibilidad cutanea frente a M.leprae y M. marinum en los pacientes virchowianos, quiescentes y reaccionales. La respuesta de la IMC frente a todos los antigenos micobacterianos se encontro aumentada en los pacientes tuberculoides, y se observo una respuesta debil frente a M. leprae y M.marinum en los controles sanos. Los resultados obtenidos muestran una estrecha correlacion entre la IMC frente a M. leprae y M. marinum en todos los casos, la cual podria expresar reactividad cruzada entre ambos antigenos