Browsing by Author "Traviña, Remia D."
Experimental transmission of hepatopancreatic parvovirus (HPV) infection in Penaeus monodon postlarvae ES Catap & RD Traviña - In Diseases in Asian Aquaculture V : Proceedings of the Fifth Symposium on Diseases in Asian Aquaculture 24-28 November 2002, Queensland, Australia, 2005 - Fish Health Section, Asian Fisheries SocietyHepatopancreatic parvovirus (HPV) infection in penaeid shrimps was first reported in various countries of the Asia-Pacific region in mid-1980. The virus affects the hepatopancreas of postlarvae and juveniles, usually leading to slow growth and mortality during the early stage of culture. At present, there is no established experimental model of infection in Penaeus monodon, a susceptible species, since there has not been any report of successful HPV transmission under laboratory conditions. Therefore, experiments were undertaken to induce HPV infection by feeding P. monodon postlarvae (PL) with virusinfected PL. Postlarval P. monodon (PL-16), initially examined to be free from HPV, were found HPV-positive 24 hours after they were fed with the infected material. Percentage of infection was from 30% (day 1) to 100% (day 7) based on the examination of wet mounts of hepatopancreas (squashed tissue) stained with malachite green and through histopathology. This is the first report of a successful horizontal transmission of HPV in P. monodon PL. This infection model could be used to study the pathogen further and would permit controlled experiments to be undertaken in order to identify methods of prevention and control.
Conference paperCR Lavilla-Pitogo, MG Paner & RD Traviña - In CR Lavilla-Pitogo & ER Cruz-Lacierda (Eds.), Diseases in Asian aquaculture IV: proceedings of the Fourth Symposium on Diseases in Asian Aquaculture, 22-26 November 1999, Cebu City, Philippines, 2002 - Fish Health Section, Asian Fisheries SocietyIn the course of routine microscopic analysis of hatchery-reared Penaeus monodon postlarvae, several batches were found with hindgut abnormalities not previously described in shrimp postlarvae. The abnormality was named swollen hindgut syndrome (SHG) because it affected mainly the hindgut. Postlarvae with SHG showed enlargement and distention of the hindgut folds and its junction with the midgut, although in some cases swelling also occurred in the midgut of the sixth abdominal segment. Over a five-year period, the yearly prevalence of SHG ranged from 6 to 13% of all batches examined. No seasonal pattern was observed as SHG occurred year-round. Despite the numerous samples obtained, SHG has not been associated with specific predisposing factors in the hatchery. The abnormality caused cessation of the rhythmic movements of the hindgut-midgut junction resulting to failure of affected postlarvae to excrete fecal pellets. Swollen hindgut syndrome, although reversible to some extent, caused mortality and significant size variation within batches of postlarvae resulting in their unsuitability for stocking in grow-out farms.