Browsing by Author "de la Peña, Leobert D."
Acute hepatopancreatic necrosis disease (AHPND) outbreaks in Penaeus vannamei and P. monodon cultured in the Philippines LD de la Peña, NAR Cabillon, DD Catedral, EC Amar, RC Usero, WD Monotilla, AT Calpe, DD Fernandez & CP Saloma -
Diseases of Aquatic Organisms, 2015 - Inter ResearchAcute hepatopancreatic necrosis disease (AHPND) has recently emerged as a serious disease of cultured shrimp. It has also been described as early mortality syndrome (EMS) due to mass mortalities occurring within 20 to 30 d after stocking of ponds with postlarvae. Here, Penaeus vannamei and Penaeus monodon from shrimp farms in the Philippines were examined for the toxin-producing strain of Vibrio parahaemolyticus due to AHPND-like symptoms occurring in marketable size shrimp. In the P. vannamei, histology revealed typical AHPND pathology, such as sloughing of undifferentiated cells in the hepatopancreatic tubule epithelium. Analysis using the IQ2000 AHPND/EMS Toxin 1 PCR test generated 218 bp and 432 bp amplicons confirmative of the toxin-producing strain of V. parahaemolyticus among shrimp sampled from 8 of 9 ponds. In the P. monodon, histology revealed massive sloughing of undifferentiated cells of the hepatopancreatic tubule epithelium in the absence of basophilic bacterial cells. PCR testing generated the 2 amplicons confirmatory for AHPND among shrimp sampled from 5 of 7 ponds. This study confirms the presence of AHPND in P. vannamei and P. monodon farmed in the Philippines and suggests that the disease can also impact late-stage juvenile shrimp.
ArticleThe hatchery system for Penaeus monodon evolved from the Japanese community culture system to the modified Galveston method and this shift in culture technique triggered the outbreak of diseases due to opportunistic bacteria. Whereas, sporadic infestation with filamentous bacteria and shell disease were the main bacterial diseases seen in earlier larval culture systems, hatcheries using the modified Galveston method experienced disease outbreaks due to systemic bacterial infection. Although several types of vibrios have been implicated in the epizootics, the dominant species seen were non-sucrose-fermenting vibrios, mainly luminescent Vibrio harveyi. To understand the course of infection, the entry of bacteria in the hatchery was investigated by determining the components and additives which encouraged their growth and dominance. As a result, several approaches to prevent and control bacterial disease have been implemented such as water treatment, hygienic spawning and egg handling, maintaining ecological balance within the system, and chemotherapy. In shrimp grow-out culture, early reports of bacterial problems were limited to shell disease, filamentous bacterial infestation and tail rot. In the last quarter of 1993, however, mass mortality associated with massive bacterial infection in the digestive organ of shrimp started occurring and contributed largely to the collapse of shrimp grow-out activities. An epidemiological study was conducted to understand the spread of infection. Several approaches to prevent or control the problem have been attempted such as the use of reservoirs, water treatment, chemotherapy, maintaining ecological balance within the system through the application of probiotics, and other system modifications.
ArticleLD de la Peña, K Mori, GF Quinitio, DS Chavez, JD Toledo, VS Suarnaba, Y Maeno, I Kiryu & T Nakai -
Bulletin of the European Association of Fish Pathologists, 2008 - European Association of Fish PathologistsViral nervous necrosis caused by betanodaviruses is one of the most devastating diseases in cultured marine finfish. In the Philippines, mass mortalities occurred in sea bass, Lates calcarifer larvae and grouper, Epinephelus coioides broodstock. The virus was isolated using SSN-1 fish cell line and confirmed by PCR. Cytopathic effect started to develop in the cell line 2 days post infection (p.i) with tissue filtrates until the cells completely disintegrated and detached from the flask at 5 days p.i. and the viral protein was detected by immunofluorescence. Sequence analysis revealed that VNN isolated from the brain of grouper broodstock and sea bass larvae were 98.6% similar. Sequence analysis between the Philippine isolates and red-spotted grouper nervous necrosis virus (RGNNV) genotype is 96.9% similar as compared to 72.0% and 64.0% similar with the barfin flounder nervous necrosis virus (BFNNV) and tiger puffer nervous necrosis virus (TPNNV) genotypes, respectively. These results confirm that the Philippine isolates belong to RGNNV genotype.