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ARS Home » Northeast Area » Leetown, West Virginia » Cool and Cold Water Aquaculture Research » Research » Publications at this Location » Publication #305805
Title: Weissellosis – An important emerging disease in farmed rainbow trout

Author
item Welch, Timothy - Tim
item Marancik, David
item GOOD, CHRISTOPHER - Freshwater Institute

Submitted to: International Aquatic Animal Health Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2014
Publication Date: 9/4/2014
Citation: Welch, T.J., Marancik, D.P., Good, C. 2014. Weissellosis – An important emerging disease in farmed rainbow trout [abstract]. International Aquatic Animal Health Symposium Proceedings. Paper No. 30A.

Interpretive Summary:

Technical Abstract: Since 2007, disease outbreaks associated with Weissella sp. bacteria in cultured rainbow trout have been reported on farms in China and Brazil. In the summer and fall of 2011, we visited two trout farms in North Carolina to investigate reports of severe, prolonged mortalities in larger fish approaching market size (0.5 -1.0 kg). Weissella sp. were isolated from sampled moribund fish, and gene sequence analysis revealed 99% homology to isolates collected from the Chinese and Brazilian outbreaks. Laboratory-based challenge experiments replicated both the disease signs and induction of mortality in exposed healthy rainbow trout, and the pathogen was readily re-isolated from experimentally infected fish showing signs of infection. Weissellosis reoccurred in 2012 on one of the North Carolina farms, demonstrating environmental persistence of the agent through the winter months, and suggesting that, without intervention, the pathogen has the potential to become a lasting and endemic disease problem in USA farmed rainbow trout. In this presentation, we describe the ongoing disease situation in North Carolina, as well as the development of an experimental vaccine to control weissellosis.