This I-CORPS team proposal will investigate the further development of technology that allows the detection and control of the emerging bacterial pathogen Aeromonas hydrophila in aquaculture farmed catfish. Specifically, this technology looks at A. hydrophila-specific diagnostic assays that use 1) growth-based, 2) antibody-based, or 3) DNA-based methods, as well as for a vaccine to prevent disease in catfish. Researchers used next-generation sequencing to identify unique genetic elements present in epidemic A. hydrophila. Based on this knowledge, they have developed growth-based, antibody-based, and gene-specific diagnostic assays specific to epidemic A. hydrophila, and a vaccine strain that can be used for disease prevention
Catfish farming is an important aquaculture sector in the USA. Beginning in 2009, epidemic outbreaks of disease due to Aeromonas hydrophila emerged in catfish ponds, causing the annual loss of millions of pounds of catfish. These losses have threatened economic sustainability in the catfish industry, and supports related sectors such as the animal feed industry, restaurants, among others. Since there are few currently available diagnostic or control products targeting the epidemic A. hydrophila, the team hypothesizes that these technologies have a significant impact in the community. These technologies have the ability to significantly reduce losses due to A. hydrophila that are anticipated to continue to be in excess of 3 million pounds of food-size catfish per year. By helping to improve biosecurity, the diagnostic assays can be an important tool in preventing the spread of this disease to other regions in the United States (e.g., Mississippi, Louisiana and Arkansas).
The major objectives for this NSF I-CORPS project were to evaluate the commercial potential for technology to detect and control infectious bacterial pathogens in the aquaculture industry. Specifically, we evaluated commercial prospects for technology that could detect the bacterial pathogen Aeromonas hydrophila that is causing epidemic outbreaks of disease in US-farmed catfish, and technology to control this disease using an attenuated vaccine and/or beneficial probiotic bacteria that can be applied to fish feed. Through discussions with stake-holders in the aquaculture industry, we discovered that the market for disease diagnostics was too small to warrant commercial development; however, this may change over time once there are approved therapeutic agents (e.g., vaccine, probiotics, or medicated feed). In order for a fish farmer to apply one of these disease treatments, there will be a need to have a positive test for the infectious agent, therefore increasing the need for diagnostic assays specific to the epidemic strain of Aeromonas hydrophila. In discussions with members of the aquaculture industry, we discovered that approval for the first therapeutant is expected in late 2014, and that demand for diagnostic assays should be increased soon. One of the major findings from this I-CORPS project was that there is considerable interest and need for disease control. Overall, there is greater potential for commercial development of the probiotic strains given their ability to control multiple bacterial and fungal diseases (and perhaps viral) and to be used in multiple fish species. In addition, we discovered a novel application of probiotics for control of Salmonella in specific species of fish that are raised in Brazil for export to European markets; and fortunately, we have already selected probiotic strains for Salmonella control as a separate research project focused on poultry pathogens. The commercial prospects for the vaccine was complicated by previous bad experiences by stake-holders in the aquaculture industry with vaccines that targeted other fish pathogens and were largely ineffective. This was an unexpected finding, given the significant academic literature focused on vaccine development for aquaculture use. The implication of this finding is that significant pond-scale trials will need to be conducted to demonstrate efficacy of a vaccine prior to acceptance an adoption of this technology by aquaculture stake-holders. We found this I-CORPS program enermously helpful in understanding the commercial potential for these technologies!
