Conjunctivitis caused by a nutritionally variant streptococcus.
We report on a case of conjunctivitis caused by a nutritionally variant streptococcus in a newborn infant.
Biomedical subjects
Publications and source records attributed to H Barrios.
We report on a case of conjunctivitis caused by a nutritionally variant streptococcus in a newborn infant.
A new attenuation marker to distinguish a virulent strain (XJJV) from an attenuated strain (XJC13JV or XJOJV) of Junin virus by means of the humoral and cellular responses to unrelated antigens was studied in guinea pigs. Strain XJJV suppressed the humoral immune response, as shown by the lower titers of precipitating antibody to ovalbumin. The concomitant decrease in serum complement level contributed to a milder Arthus cutaneous reactivity. In contrast, the attenuated strains did not decrease the humoral response. The pathogenic strain suppressed cell-mediated immunity, as demonstrated by decreased contact sensitivity to 2,4-dinitro-1-fluorobenzene and by depression of delayed skin reactions to tuberculin purified protein derivative. When attenuated strains were used, such suppressive effects were not observed. For virulent strain XJJV, virus replication in lymphoid organs and immunosuppressive effects were correlated. These findings provide a further means to differentiate between virulent and attenuated strains of Junin virus for the purpose of vaccine control of Argentine hemorrhagic fever.
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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.
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.