Survey of infectious diseases in Penaeus vannamei (Boone) from Costa Rica shrimp farms during 2017 and 2018

Introduction: Costa Rica has suitable environmental features to produce farmed shrimp, but infectious diseases are a major hurdle. Scarce information exists on the presence of viruses or bacterial pathogens in farmed shrimp in Costa Rica. Materials and methods: This study surveyed three pathogens of farmed shrimp Penaeus vannamei at 14 facilities located along the Gulf of Nicoya and the Pacific coast, Guanacaste and Puntarenas provinces. Samplings were done during the wet period of 2017 and the dry period of 2018. A total of 970 shrimps were collected, euthanized and dissected to obtain the foregut, hepatopancreas, gills and pleopods. Each organ was separately pooled (n = 10 shrimp) and fixed in 70% ethanol for DNA extraction and endpoint PCR was done to detect Acute Hepatopancreas Necrosis Disease (AHPND), Whispovirus (WSSV), and Penstylhamaparvovirus (IHHNV). Results: AHPND was detected in three farms in the Gulf of Nicoya and in one farm each in the central and south Pacific, Puntarenas province. IHHNV was detected in both samplings in the Gulf of Nicoya in three farms, and one farm each in central and south Pacific regions, Puntarenas province. Conversely, WSSV was not found on any sampled shrimp farm. Sequence analyses confirmed the presence of both AHPND and IHHNV. Both pathogens had a scarce presence in shrimp farms in Costa Rica and probably were introduced through imported pathogen-infected nauplii or postlarvae from neighboring countries. Hence, stringent sanitary measures are required to reduce the risk of pathogen dispersion to other shrimp farms in Costa Rica. Conclusions: This study confirmed the presence of AHPND and IHHNV in Costa Rica using endpoint PCR and sequencing in farms located in the Gulf of Nicoya in the Guanacaste and Puntarenas provinces. The presence of pathogens in Costa Rica is probably due to the importation of infected nauplii and shrimp larvae.