By Aquaculture and Aquatic Resources Management (AARM)
Pathum Thani, Thailand – Streptococcosis remains one of the most devastating bacterial diseases in tilapia (Oreochromis spp.) aquaculture worldwide. Caused by Streptococcus agalactiae, the disease can result in losses of up to 70%, threatening farm productivity, profitability, and sustainability.
To address this critical challenge, the Laboratory of Aquatic Animal Health and Alternatives to Antibiotics (A4 Lab) at the Asian Institute of Technology (AIT) has developed and tested a new bivalent vaccine (OreoVac Biva-S) designed to help prevent Streptococcosis in tilapia. The work was led by Associate Professor, Dr. Ha Thanh Dong, with contributions from PhD candidate Mr. Nguyen Tien Vinh, in collaboration with academic partner Dr. Saengchan Senapin from CENTEX Shrimp (BIOTEC/NSTDA & Mahidol University) and industry partner Nam Sai Farms Co., Ltd.
A Practical, Affordable Solution
OreoVac Biva-S is built on a “back-to-basics” heat-killed vaccine platform, prioritizing safety, affordability, and ease of production to keep costs low for farmers. The vaccine formulation comprises local strains of S. agalactiae, specifically serotypes Ia and III, ensuring targeted and effective protection in regional farming conditions.
Recognizing the diversity of farming systems, OreoVac Biva-S offers flexibility through three administration routes (i) injection; (ii) immersion; and (iii) oral delivery. This versatility enables farmers to select the most suitable vaccination strategy based on fish size, production scale, and operational capacity.
Figure 1: OreoVac Biva-S prototype design for three administration routes
Proven Farm Performance
Field results demonstrate strong protective efficacy, with up to 94.5% survival in vaccinated fish compared to 66.8% in non-vaccinated fish, resulting in a 45% increase in production performance and nearly a two-fold increase in profit per kilogram of fish. In addition, vaccinated fish showed increased resilience during the high temperature stress period of the Streptococcosis season, further supporting stable production under challenging farming conditions. These outcomes highlight not only improved fish health but also significant economic benefits for producers. The study was published in Frontiers in Veterinary Science in 2026.
Figure 2: Line graph showing cumulative mortality in control and vaccinated groups over 24 weeks, with water temperature. Control mortality peaks at week 13, while vaccinated fish remain low; temperature exceeds 32 °C during the mortality peak.
Supporting Sustainable Aquaculture
By reducing reliance on antibiotics, OreoVac Biva-S aligns with global efforts to combat antimicrobial resistance (AMR) and promote more responsible aquaculture practices. The vaccine provides farmers with a science-based, practical tool to safeguard stock health while strengthening long-term industry sustainability.
“With OreoVac Biva-S, we seek to offer farmers an effective and affordable alternative to antibiotics, supporting a more sustainable tilapia industry. In a sector where margins are tight, a simpler solution is not a compromise, but a stronger competitive advantage,” said Dr. Ha Thanh Dong.
Figure 3: Floating cage culture of hybrid tilapia in Thailand.
This innovation was developed under a funded project as part of the Innovative Veterinary Solutions for Antimicrobial Resistance (InnoVet-AMR) initiative. The initiative is supported through a partnership between Canada’s International Development Research Centre (IDRC) and the UK government’s Global AMR Innovation Fund (GAMRIF), which is part of the Department of Health and Social Care (DHSC). The initiative aims to reduce AMR in ruminant and aquaculture production while mitigating associated risks to human health.
For more information about OreoVac Biva-S and collaboration opportunities, please contact:
Associate Professor, Dr. Ha Thanh Dong
Laboratory of Aquatic Animal Health and Alternatives to Antibiotics (A4 Lab)
Aquaculture and Aquatic Resources Management (AARM) Program
Faculty of Food, Agriculture, and Natural Resources (FANR)
Asian Institute of Technology (AIT)
Email: [email protected]
