Immune Responses in WSSV-Exposed Shrimp

White Spot Syndrome Virus (WSSV) is one of the most destructive viral pathogens affecting shrimp aquaculture, causing major economic losses and threatening food security. The virus poses an increasing risk to emerging aquaculture regions in Africa, where sustainable shrimp farming supports livelihoods and the development of the blue economy. This study investigated the early immune responses of Penaeus vannamei exposed to ethanol-inactivated WSSV to identify immune biomarkers associated with shrimp health and disease resilience. Experimental shrimp were exposed to ethanol-inactivated WSSV and sampled between 0 and 72 hours post-infection (hpi). Key immune parameters analyzed included Total Hemocyte Count (THC), Differential Hemocyte Count (DHC), Phenol Oxidase Activity (POA), and Superoxide Dismutase Activity (SOD). These parameters were evaluated to characterize cellular immune responses and antioxidant defense mechanisms following viral exposure. Results showed a significant increase in THC between 12hpi and 18hpi in WSSV-exposed shrimp, indicating rapid activation and mobilization of cellular immune defenses during the acute response phase. Elevated hemocyte levels suggested enhanced immune surveillance and pathogen recognition immediately after viral exposure. DHC remained relatively stable throughout the experiment, indicating minimal variation in hemocyte subpopulations during early immune activation. POA showed limited fluctuation, suggesting that melanization responses were not strongly stimulated under the experimental conditions. In contrast, SOD activity varied significantly across sampling intervals, demonstrating activation of antioxidant defense pathways involved in oxidative stress regulation and cellular protection during immune stimulation. The combined increase in THC and SOD activity highlights coordinated immune and antioxidant responses in shrimp exposed to WSSV. 12hpi–18hpi was identified as a critical window for immune characterization in Penaeus vannamei, with THC emerging as a sensitive biomarker for early immune activation. This study provides baseline information for shrimp health monitoring, development of immunostimulant strategies, strengthening aquaculture biosecurity, and the support of resilient and sustainable shrimp farming systems.

Key words

WSSV, shrimp immunity, biomarkers, aquaculture, Penaeus vannamei

Preferred presentation format: Oral presentation