Epidemiological Surveillance of Enterocytozoon hepatopenaei (EHP) in Pacific White Shrimp (Litopenaeus vannamei)

Abstract

Shrimp represent a critical economic asset for Thailand, characterized by high market value and substantial production volumes. Consequently, robust health management and optimized farm practices are essential for enhancing productivity and mitigating losses attributed to pathogenic outbreaks. Epidemiological surveillance serves as a fundamental strategy for strategic planning, biosecurity monitoring, and the containment of infectious diseases. This study used Polymerase Chain Reaction (PCR) techniques to investigate the prevalence and distribution of Enterocytozoon hepatopenaei (EHP) in Pacific white shrimp (Litopenaeus vannamei) within Nakhon Si Thammarat and its nearby provinces. EHP significantly decreases metabolic, and immunological alterations in the host, showing clinically as White Feces Syndrome (WFS) and a marked retardation in growth rates. Furthermore, EHP infection serves as a predisposing factor that increases the risk of Acute Hepatopancreatic Necrosis Disease (AHPND) (Aranguren et al., 2017), a highly virulent condition resulting in yield losses and economic devastation. Shrimp samples were sampling across 15 locations, including shrimp farms and markets. PCR analysis revealed EHP-positive results in 10 of the 15 sampled sites. These positive samples originated from high-density aquaculture zones, adjacent areas, and natural habitats. These findings reflect a transmission pattern where EHP circulates between farm and wild populations (Wan Sajiri et al., 2021); however, intensive aquaculture practices significantly amplify the detectability and spread of the pathogen. Therefore, good farming management remains the primary mechanism for preventing EHP transmission. The development of robust preventative measures and effective control protocols is important to minimize biological risks and secure the socio-economic stability of the aquaculture sector.