Protecting Tilapia Production: Field Evidence that Vaccination Saves Fish and Stabilizes Yields

Streptococcosis and a viral disease known as infectious spleen and kidney necrosis (ISKNV) are two of the most consequential infectious threats to tilapia farmers worldwide.

A recent field trial in a Brazilian reservoir with a history of both pathogens tested whether adding protection against ISKNV to routine vaccination for Streptococcus would improve survival under real production conditions.

Juvenile Nile tilapia were raised in infection‑free ponds, split into two groups, and vaccinated according to two strategies. Both groups received vaccination against the common Streptococcus pathogens; one group received an additional vaccine targeting ISKNV. After the recommended rest period the fish were transferred to grow‑out cages in the reservoir and followed through the full production cycle, with all mortalities recorded.

At harvest the difference was clear. The group vaccinated only against Streptococcus achieved a 71.9% survival rate, while the group that also received ISKNV protection reached 95.3% survival, which is an improvement of 23.4 percentage points. Mortality in the Streptococcus‑only group clustered around periods of environmental thermal variation, producing mortality peaks; by contrast, the group that had combined protection maintained a steady cumulative survival curve. The trial found no safety concerns with the combined program.

Why this matters

• Higher, more stable survival directly reduces production risk and increases yield — critical outcomes for farm profitability and food supply.
• ISKNV can cause sudden, temperature‑linked mortality events that are difficult to manage once underway; preventive vaccination markedly reduces that risk.
• Integrating protection for both bacterial and viral threats into vaccination programs supports more resilient farm performance in environments where multiple pathogens are present.

This real‑world trial highlights vaccination as a practical, preventive tool that can substantially improve tilapia survival and stabilize production in the face of common infectious challenges. For farms operating in regions at risk from both streptococcal diseases and ISKNV, combined vaccination strategies warrant strong consideration as part of a broader health‑management plan that also includes good husbandry, biosecurity, and monitoring.

References:

EFEITO NA TAXA DE SOBREVIVÊNCIA DA TILÁPIA DO NILO Oreochromis niloticus IMUNIZADA PARA Streptococcus agalactiae sorotipo ib E Streptococcus iniae EM COMBINAÇÃO COM ISKNV