ARS | Publication request: Concurrent Infections (Parasitism and Bacterial Disease) in Tilapia

Submitted to: International Symposium on Talipia in Aquaculture
Publication Type: Abstract
Publication Acceptance Date: August 1, 2008
Publication Date: October 12, 2008
Citation: Shoemaker, C.A., Xu, D., Klesius, P.H., Evans, J.J. 2008. Concurrent Infections (Parasitism and Bacterial Disease) in Tilapia. 8th International Symposium on Talipia in Aquaculture. Cairo, Egypt October 12-14, 2008. p. 115.

Technical Abstract: Most laboratory disease studies in tilapia to date have focused on a single parasite or a single bacterial pathogen. In intensive tilapia aquaculture, the reality of a single disease agent resulting in death-loss may be small. More likely, multiple disease agents are present (i.e., parasites, bacteria and/or a combination) and responsible for disease losses. This paper will focus on concurrent infections or the potential for concurrent infections in tilapia. We will highlight a recent study completed at our laboratory on parasitism with a monogenetic trematode and subsequent bacterial infection with Streptococcus iniae in Nile tilapia (Oreochromis niloticus). Concurrent experimental infection with Gyrodactylus niloticus and S. iniae resulted in significantly higher mortality in tilapia (abour 42%) as compared to immersion infection with S. iniae alone (7%) and parasitism with G. niloticus only (0%). Gyrodactylus niloticus presumably provided a portal of entry for invasive bacteria due to damage of the fish epithelium. Interestingly, G. niloticus was also found to harbor viable S. iniae at 24 and 72 h post infection suggesting that G. niloticus may vector S. iniae from fish to fish.