Addressing re-emergent Streptococcus agalactiae in tilapia production through international collaboration

Authors: Lafrentz, Benjamin

Submitted to: Caribbean and Latin American Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: 9/3/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Streptococcus agalactiae is the most important bacterial pathogen impacting global tilapia aquaculture. Ten different capsular types (CPS) of S. agalactiae are recognized, and of these, CPS types Ia, Ib, and III are the most prevalent in the global tilapia industry. Historically, streptococcosis caused by S. agalactiae in North America, Central America, and South America has been associated with disease in tilapia of sizes > 100 - 300 g and typically involved CPS type Ib and occasionally CPS type Ia. Of importance is the recent emergence of a CPS type Ia (referred to as Ia-2021) that is causing large scale losses in fry, fingerlings, grow-out and broodstock. The disease caused by the CPS type Ia-2021 is drastically different than CPS Ib and presents as an acute bacteremia with severe hemorrhaging and intussusception of the intestines. Notably, field observations suggest that vaccines previously used in the industry, based on CPS type Ib, are not effective against the CPS Ia-2021. The goal of this plenary presentation is to provide an overview of an international collaboration focused on basic and applied research to increase our understanding of the host, pathogen and environmental interactions surrounding streptococcosis caused by CPS type Ia-2021. The goal of this research is to develop practical solutions for tilapia farmers to utilize to prevent this disease from occurring and enhance the profitability and sustainability of tilapia production.

Technical Abstract: Streptococcus agalactiae is the most important bacterial pathogen impacting global tilapia aquaculture. Ten different capsular types (CPS) of S. agalactiae are recognized, and of these, CPS types Ia, Ib, and III are the most prevalent in the global tilapia industry. Historically, streptococcosis caused by S. agalactiae in North America, Central America, and South America has been associated with disease in tilapia of sizes > 100 - 300 g and typically involved CPS type Ib and occasionally CPS type Ia. Of importance is the recent emergence of a CPS type Ia (referred to as Ia-2021) that is causing large scale losses in fry, fingerlings, grow-out and broodstock. The disease caused by the CPS type Ia-2021 is drastically different than CPS Ib and presents as an acute bacteremia with severe hemorrhaging and intussusception of the intestines. Notably, field observations suggest that vaccines previously used in the industry, based on CPS type Ib, are not effective against the CPS Ia-2021. The goal of this plenary presentation is to provide an overview of an international collaboration focused on basic and applied research to increase our understanding of the host, pathogen and environmental interactions surrounding streptococcosis caused by CPS type Ia-2021. The goal of this research is to develop practical solutions for tilapia farmers to utilize to prevent this disease from occurring and enhance the profitability and sustainability of tilapia production.