Prevalence and phylogenetics of infectious hypodermal and hematopoietic necrosis virus (IHHNV) in market-sold Litopenaeus vannamei in Luzon, Philippines

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a World Organization for Animal Health (OIE)-classified notifiable crustacean disease. There is limited information on the current status of IHHNV in the Philippines. Thus, this research focuses on collecting samples from various municipality markets of known shrimp producers in Central Luzon to provide an update on the status of IHHNV. These samples were subjected to IHHNV detection using PCR. Results showed that 56 out of the 276 (~20%) samples were positive for IHHNV. This indicates that IHHNV persists in Philippine shrimps despite preventive measures such as testing of broodstock. Furthermore, the sequences of the isolates acquired from different municipalities reveal a high degree of similarity, suggesting transboundary movement of the infection. Our findings also support research that demonstrated a strong link between IHHNV strains in the western hemisphere and those in the Philippines. Our data suggest that farm-monitoring processes must be tightened and strictly implemented to prevent the spread of IHHNV.