Asian seabass (Lates calcarifer) is an important farmed species in Southeast Asian aquaculture, valued for its nutritional benefits and market appeal. However, the widespread outbreak of scale drop disease virus (SDDV) has caused major production losses, posing serious financial risks to farmers and undermining food security targets. With mortality rates reaching up to 70%, there is an urgent need for an effective vaccine to protect seabass farming and reduce the impact of SDDV.
At A*STAR IDL, we focus on vaccine development and have taken a multipronged approach targeting viral protein fragments to stimulate adaptive immune responses in the host fish. In this study, 141 juvenile seabass (10 g ± 2) were divided into six groups. Four groups were vaccinated at week 0 and boosted at week 3 with either a B cell vaccine, T cell vaccine, combination B and T cell vaccine, or a subunit vaccine. The remaining two groups were unvaccinated controls.
Six weeks after priming, fish were challenged intraperitoneally with purified SDDV. At three weeks post-infection, the unvaccinated group showed 48% mortality, while the unchallenged control group had no mortality. Among the vaccinated groups, the combination epitope vaccine group showed the highest survival rate, indicating strong protection.
In summary, the combination epitope vaccine shows promising potential in protecting Asian seabass against SDDV. Further optimisation may improve efficacy and support disease management in the aquaculture sector.