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Dynamics of piscine francisellosis differs amongst tilapia species ( Oreochromis spp.) in a controlled challenge with Francisella noatunensis subsp. orientalis
Author(s) -
KlingerBowen R,
Tamaru C,
McGovernHopkins K,
Li Y,
Sithole F,
Kearney M T,
Francis S,
Soto E
Publication year - 2016
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.12461
Subject(s) - oreochromis mossambicus , tilapia , biology , francisella , fish farming , veterinary medicine , oreochromis , fish <actinopterygii> , fishery , freshwater fish , zoology , aquaculture , virulence , biochemistry , medicine , francisella tularensis , gene
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 ( GE s) in water were similar in all treatments 1 h post‐challenge; however, significantly lower Fno GE s 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 GE s 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.