Effects of temperature and salt concentration on Francisella noatunensis subsp. orientalis infections in Nile tilapia Oreochromis niloticus

Esteban Soto Martinez, Stephanie B. Abrams, Floyd Revan

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Little is known about the environmental conditions that allow Francisella noatunensis subsp. orientalis, a worldwide emergent bacterial fish pathogen, to colonize and infect wild and cultured fish. We evaluated the effect of temperature and salinity on the infectivity of F. noatunensis subsp. orientalis in Nile tilapia Oreochromis niloticus (L). Immersion challenges of tilapia with F. noatunensis subsp. orientalis at water temperatures of 25 and 30°C in both sea and fresh water were conducted for 14 d. Morbidity and mortality were recorded daily, and at the completion of the study, a quantitative assessment of the splenic bacterial burden was performed in surviving fish. Fish maintained at 25°C developed francisellosis and had considerably higher mortality and splenic bacterial concentrations compared to control fish and fish maintained at 30°C. Moreover, increasing the water temperature from 25 to 30°C prevented the development of clinical signs and mortality in Francisella-challenged fish. In conclusion, temperature significantly influenced the development of francisellosis in tilapia, whereas salinity had no effect. Our findings may be useful in the establishment of improved prophylactic practices and in the management of outbreaks of francisellosis in the aquaculture industry.

Original languageEnglish (US)
Pages (from-to)217-223
Number of pages7
JournalDiseases of Aquatic Organisms
Volume101
Issue number3
DOIs
StatePublished - Nov 19 2012
Externally publishedYes

Keywords

  • Aquaculture
  • Environment
  • Francisellosis
  • Pathogenesis

ASJC Scopus subject areas

  • Aquatic Science
  • Ecology, Evolution, Behavior and Systematics

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