First identification of Francisella noatunensis subsp. orientalis causing mortality in mexican tilapia Oreochromis spp

Cesar Ortega, Gerardo Mancera, Ricardo Enríquez, Augusto Vargas, Simón Martínez, Raúl Fajardo, Ruben Avendaño-Herrera, María José Navarrete, Alex Romero

Resultado de la investigación: Contribución a una revistaArtículo

19 Citas (Scopus)

Resumen

Francisellosis, an emerging disease in tilapia Oreochromis spp., is caused by the facultative, intracellular bacterium Francisella noatunensis subsp. orientalis, which is present in various countries where tilapia farming is commercially important. We confirmed the presence of francisellosis in Mexican tilapia cultures in association with an outbreak during the second semester of 2012. Broodstock fish presented a mortality rate of approximately 40%, and disease was characterized by histologically classified granulomas, or whitish nodules, in different organs, mainly the spleen and kidney. Through DNA obtained from infected tissue and pure cultures in a cysteine heart medium supplemented with hemoglobin, F. noatunensis subsp. orientalis was initially confirmed through the amplification and analysis of the 16S rRNA gene and the internal transcribed spacer region. Phylogenetic analysis of these genes demonstrated close similarity with previously reported F. noatunensis subsp. orientalis sequences obtained from nfected tilapia from various countries. The identification of this subspecies as the causative agent of the outbreak was confirmed using the iglC gene as a target sequence, which showed 99.5% identity to 2 F. noatunensis subsp. orientalis strains (Ethime-1 and Toba04). These findings represent the first documented occurrence of francisellosis in Mexican tilapia cultures, which highlights the importance of establishing preventative measures to minimize the spread of this disease within the Mexican aqua - culture industry.

Idioma originalInglés
Páginas (desde-hasta)205-215
Número de páginas11
PublicaciónDiseases of Aquatic Organisms
Volumen120
N.º3
DOI
EstadoPublicada - 9 ago 2016

Áreas temáticas de ASJC Scopus

  • Ecología, evolución, comportamiento y sistemática
  • Ciencias acuáticas

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    Ortega, C., Mancera, G., Enríquez, R., Vargas, A., Martínez, S., Fajardo, R., Avendaño-Herrera, R., Navarrete, M. J., & Romero, A. (2016). First identification of Francisella noatunensis subsp. orientalis causing mortality in mexican tilapia Oreochromis spp. Diseases of Aquatic Organisms, 120(3), 205-215. https://doi.org/10.3354/dao02999