Dynamics of piscine francisellosis differs amongst tilapia species (Oreochromis spp.) in a controlled challenge with Francisella noatunensis subsp. orientalis |
| |
| Authors: | R Klinger‐Bowen C Tamaru K McGovern‐Hopkins Y Li F Sithole M T Kearney S Francis E Soto |
| |
| Affiliation: | 1. Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii Manoa, Honolulu, HI, USA;2. Office of Research Compliance, Animal Veterinary Services, University of Hawaii Manoa, Honolulu, HI, USA;3. Department of Human Nutrition, Food and Animal Science, College of Tropical Agriculture and Human Resources, University of Hawaii Manoa, Honolulu, HI, USA;4. Department of Biomedical Sciences, Ross University‐School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis;5. Department of Pathobiology, Louisiana State University‐School of Veterinary Medicine, Baton Rouge, LA, USA;6. Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA |
| |
| Abstract: | A 25‐week immersion challenge was conducted exposing Oreochromis mossambicus, Oreochromis aureus and Oreochromis urolepis hornorum to Francisella noatunensis subsp. orientalis (Fno). Two populations were compared for each fish species; ‘resident fish’ were defined as fish maintained in tanks since week 0 of challenge, whereas ‘naïve fish’ were defined as fish added to tanks once temperature in water reached <26 °C at 21 weeks post‐challenge. Fno genome equivalents (GEs) in water were similar in all treatments 1 h post‐challenge; however, significantly lower Fno GEs were detected 2 weeks post‐challenge in all tanks, and the only treatment with detectable Fno GE after 4 weeks of challenge were the O. mossambicus tanks. Twenty‐one weeks post‐challenge, naïve fish were stocked with ‘resident’ cohorts. Over a 4‐week period, mortalities occurred consistently only in O. mossambicus naïve cohorts. Overall presence of granulomas in spleen of survivors was similar (>55%) in all resident populations; however, in naïve populations, only O. mossambicus presented granulomas. Similarly, only O. mossambicus presented viable Fno in the spleen of survivors, and Fno GEs were only detected in O. mossambicus, and in resident O. aureus. In conclusion, the results of this study suggest different susceptibility of tilapia species to piscine francisellosis. |
| |
| Keywords: | aquaculture
Francisella
Hawaii
Tilapia
|
|
|
