The objectives of this study were to determine the pathogenicity of a strain of Yersinia ruckeri, from an outbreak of yersiniosis in Huaraz and to characterize histopathological lesions in various organs of rainbow trout fingerlings (Oncorhynchus mykiss). One hundred fingerlings with an average weight of 7.25 g were used, divided into 5 groups of 20 individuals (four experimental and one control), kept in 30 L ponds. Experimental groups were inoculated via i.m. with 0.1 ml of the bacterial strain in concentrations of 1x104/ml (G1), 4x104/ml (G2), 1x108/ml (G3) and 4x108/ml (G4), and the control group with PBS. Clinical signs, external and internal lesions, morbidity and mortality were recorded for 12 days post-inoculation. Samples of liver, intestine, spleen, kidney, muscle and gills were collected for histopathological analysis. All fish inoculated with Y. ruckeri showed signs and lesio...

The aim of this study was to identify Y. ruckeri genotypes, according to their origin, by RAPD-PCR. Aseptic samples of spleen and kidney were taken from rainbow trout (Oncorhynchus mykiss) with clinical signs of yersiniosis in fish farms of four departments (Junín, Lima, Ancash and Puno) of Peru. The strains were cultivated on trypticase soy agar at 25 °C for 24 hours and the presumptive identification of the colonies suspected of being Y. ruckeri was made by Gram stain and biochemical tests of oxidase and catalase. Then, the identity of Y. ruckeri was confirmed by PCR. In total, 63 isolates of Y. ruckeri were obtained and analyzed by RAPD-PCR. The dendogram of genetic diversity grouped all the isolates in one cluster, closely related to the control strain Y. ruckeri ATCC 29473 (96% similarity). It was also observed that all the isolates were genetically identical (clones). It is sugge...

The objectives of this study were to determine the pathogenicity of a strain of Yersinia ruckeri, from an outbreak of yersiniosis in Huaraz and to characterize histopathological lesions in various organs of rainbow trout fingerlings (Oncorhynchus mykiss). One hundred fingerlings with an average weight of 7.25 g were used, divided into 5 groups of 20 individuals (four experimental and one control), kept in 30 L ponds. Experimental groups were inoculated via i.m. with 0.1 ml of the bacterial strain in concentrations of 1x104/ml (G1), 4x104/ml (G2), 1x108/ml (G3) and 4x108/ml (G4), and the control group with PBS. Clinical signs, external and internal lesions, morbidity and mortality were recorded for 12 days post-inoculation. Samples of liver, intestine, spleen, kidney, muscle and gills were collected for histopathological analysis. All fish inoculated with Y. ruckeri showed signs and lesio...

The aim of this study was to identify Y. ruckeri genotypes, according to their origin, by RAPD-PCR. Aseptic samples of spleen and kidney were taken from rainbow trout (Oncorhynchus mykiss) with clinical signs of yersiniosis in fish farms of four departments (Junín, Lima, Ancash and Puno) of Peru. The strains were cultivated on trypticase soy agar at 25 °C for 24 hours and the presumptive identification of the colonies suspected of being Y. ruckeri was made by Gram stain and biochemical tests of oxidase and catalase. Then, the identity of Y. ruckeri was confirmed by PCR. In total, 63 isolates of Y. ruckeri were obtained and analyzed by RAPD-PCR. The dendogram of genetic diversity grouped all the isolates in one cluster, closely related to the control strain Y. ruckeri ATCC 29473 (96% similarity). It was also observed that all the isolates were genetically identical (clones). It is sugge...