Estudio del desarrollo del síndrome Rickettsial salmonideo(srs) :|bInfección experimental de salmonidos con distintos aislados de Piscirickettsia Salmonis
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Archivos
Fecha
2001
Profesor/a Guía
Facultad/escuela
Idioma
es
Título de la revista
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Título del volumen
Editor
Universidad Andrés Bello
Nombre de Curso
Licencia CC
Licencia CC
Resumen
En la actualidad, existe consenso en que el establecimiento de medidas
efectivas de prevención y tratamiento de la Piscirickettsiosis (SRS) requiere un
mayor conocimiento del agente causal y de los factores involucrados en el desarrollo
de esta enfermedad. Al respecto, en esta tesis se plantean los primeros antecedentes
sobre la virulencia de diferentes aislados de Piscirickettsia salmonis.
Para ello, se analizó la virulencia de cuatro aislados chilenos de esta bacteria
mediante la infección experimental de alevines de trucha Arcoiris y salmón Coho.
Los aislados fueron seleccionados en función de las diferencias en el genoma de la
bacteria, mediante técnicas moleculares (ITS-patrón de migración largo y corto), el
efecto citopático en cultivo celular y su sensibilidad a los antibióticos.
Basándose en las diferencias en la manifestación de los signos clínicos y en el
análisis estadístico, se estableció que los aislados de P. salmonis denominados MH-
11 y AG-2 fueron los más virulentos, causando un 70,5% y 51,8% de mortalidad
respectivamente en trucha Arcoiris, y un 91,4% y 85%, respectivamente en salmón
Coho. Aunque los aislados de menor agresividad, LF-89 y EM-90, causaron una
mortalidad similar en trucha Arcoiris 10,9% y 13,1% respectivamente, en salmón
Coho se observó que el aislado LF-89 fue más virulento en comparación con EM-90
(29,5% y 10,9%, respectivamente); determinándose además que esta especie fue
claramente más susceptible que la trucha Arcoiris a la infección con P. salmonis.
Los resultados sugieren una asociación entre la virulencia y el patrón de
migración electroforético del ITS, observándose una mayor agresividad en los
aislados con ITS-patrón de migración largo. Además plantean una interrogante que
deberá considerarse al evaluar la virulencia de P. sal monis: la agresividad del aislado
se potenciaría al coincidir la especie de origen de éste con la especie de salmón
infectada.
At present it is clearly that to establish effective prevention and therapy against Piscirickettsiosis exhautive deeper the knowledge about the pathogen and factors envolved in the development of the disease are required. In this thesis through experimental infection of Coho salmon and Rainbow trout the virulence of four chilean P. salmonis isolates were analized. The isolates were selected considering differences in their genome (ITS-long and short electrophoretic migration pattern), the cytopathic effect in cell culture and their antibiotic sensitivity. Based on differences of pathology caused by the isolates and resusts statistical analysis it was established that P.salmonis isolates named as MH-11 and AG-2 were the most virulent worth losses reaching 70,5% and 51,8% in rainbow trout respectively and 91,4% and 85% in coho salmon respectively. The isolates P. salmonis LF-89 and EM-90, the less pathogenic causes similar mortality in trout 10,9% and 13,1% respectively. However, it has been observed that LF-89 isolate was more virulent than EM-90 isolate in Coho salmon with losses reaching 29,5% and 10,9%, respectively. Then the Coho salmon was clearly the specie more susceptible to P. salmonis infection. The results also suggest an assotiation between virulence and the P. salmonis ITS electrophoretic migration pattern isolates with ITS-long migration pattern were more virulent. Also a question arise from our results which will be considered to evaluate P. salmonis virulence: the aggressiveness of P. salmonis isolates increase when the origin salmonid specie agrees with the salmon specie infected.
At present it is clearly that to establish effective prevention and therapy against Piscirickettsiosis exhautive deeper the knowledge about the pathogen and factors envolved in the development of the disease are required. In this thesis through experimental infection of Coho salmon and Rainbow trout the virulence of four chilean P. salmonis isolates were analized. The isolates were selected considering differences in their genome (ITS-long and short electrophoretic migration pattern), the cytopathic effect in cell culture and their antibiotic sensitivity. Based on differences of pathology caused by the isolates and resusts statistical analysis it was established that P.salmonis isolates named as MH-11 and AG-2 were the most virulent worth losses reaching 70,5% and 51,8% in rainbow trout respectively and 91,4% and 85% in coho salmon respectively. The isolates P. salmonis LF-89 and EM-90, the less pathogenic causes similar mortality in trout 10,9% and 13,1% respectively. However, it has been observed that LF-89 isolate was more virulent than EM-90 isolate in Coho salmon with losses reaching 29,5% and 10,9%, respectively. Then the Coho salmon was clearly the specie more susceptible to P. salmonis infection. The results also suggest an assotiation between virulence and the P. salmonis ITS electrophoretic migration pattern isolates with ITS-long migration pattern were more virulent. Also a question arise from our results which will be considered to evaluate P. salmonis virulence: the aggressiveness of P. salmonis isolates increase when the origin salmonid specie agrees with the salmon specie infected.
Notas
Tesis (Ingeniero en Acuicultura)
Palabras clave
Salmones - Enfermedades