Rapid diagnosis of vibriosis and white spot syndrome (WSS) in the culture of shrimp, Penaeus monodon in Philippines.

Viral and bacterial pathogens have raised serious concerns in the sustainability of the shrimp culture industry in the Philippines. Heavy mortality associated with luminous vibriosis and white spot syndrome virus (WSSV) infection has been the major problem besetting the industry. Using published PCR protocols for the diagnosis of vibriosis and white spot syndrome virus (WSSV) disease in shrimp, we optimized these assays that could be suited to the shrimp aquaculture setting in the Philippines. Genomic DNAs of Vibrio spp. that exhibited luminescence as well as those that grew on thiosulfate citrate bile salt sucrose agar (TCBS) were used for the PCR amplification of the ribonuclease P (RNase P) gene. There was differential amplification of the RNase P gene based on the phenotypic characters of the Vibrio spp. Similar results were also obtained using direct colony PCR of the bacterial colonies. White spot syndrome virus was also detected in the infected shrimp and there were differences in the detection frequency in relation to the tissues used for PCR amplification. Duplex PCR was also optimized that could be used for simultaneous detection of these pathogens in shrimp.