DAO 106:229-239 (2013)  -  doi:10.3354/dao02649

Paramecium caudatum enhances transmission and infectivity of Mycobacterium marinum and M. chelonae in zebrafish Danio rerio

Tracy S. Peterson1,*, Jayde A. Ferguson2, Virginia G. Watral1, K. Nadine Mutoji3, Don G. Ennis4, Michael L. Kent1,5

1Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA
2Alaska Department of Fish and Game, Fish Pathology Laboratory, Anchorage, Alaska 99518, USA
3Department of Biology, University of Texas-San Antonio, San Antonio, Texas 78249, USA
4Department of Biology, University of Louisiana, Lafayette, Louisiana 70504, USA
5Department of Biomedical Sciences, Oregon State University, Corvallis, Oregon 97331, USA

ABSTRACT: Mycobacterial infections in laboratory zebrafish Danio rerio are common and widespread in research colonies. Mycobacteria within free-living amoebae have been shown to be transmission vectors for mycobacteriosis. Paramecium caudatum are commonly used as a first food for zebrafish, and we investigated this ciliate’s potential to serve as a vector of Mycobacterium marinum and M. chelonae. The ability of live P. caudatum to transmit these mycobacteria to larval, juvenile and adult zebrafish was evaluated. Infections were defined by histologic observation of granulomas containing acid-fast bacteria in extraintestinal locations. In both experiments, fish fed paramecia containing mycobacteria became infected at a higher incidence than controls. Larvae (exposed at 4 d post hatch) fed paramecia with M. marinum exhibited an incidence of 30% (24/80) and juveniles (exposed at 21 d post hatch) showed 31% incidence (14/45). Adult fish fed a gelatin food matrix containing mycobacteria within paramecia or mycobacteria alone for 2 wk resulted in infections when examined 8 wk after exposure as follows: M. marinum OSU 214 47% (21/45), M. marinum CH 47% (9/19), and M. chelonae 38% (5/13). In contrast, fish fed mycobacteria alone in this diet did not become infected, except for 2 fish (5%) in the M. marinum OSU 214 low-dose group. These results demonstrate that P. caudatum can act as a vector for mycobacteria. This provides a useful animal model for evaluation of natural mycobacterial infections and demonstrates the possibility of mycobacterial transmission in zebrafish facilities via contaminated paramecia cultures.


KEY WORDS: Zebrafish · Mycobacteria · Transmission · Animal model · Ciliate


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Cite this article as: Peterson TS, Ferguson JA, Watral VG, Mutoji KN, Ennis DG, Kent ML (2013) Paramecium caudatum enhances transmission and infectivity of Mycobacterium marinum and M. chelonae in zebrafish Danio rerio. Dis Aquat Org 106:229-239

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