碩士 / 國立屏東科技大學 / 獸醫學系所 / 95 / Infectious hypodermal and hematopoietic necrosis virus ( IHHNV ) has been demonstrated to cause acute epizootics and mass mortality ( 90% ) only in Penaeus stylirostris, where as infection in Litopenaeus vannamei is known to induce abnormalities in development and growth ( runt deformity syndrome; RDS ), causing economic losses between 10% and 50%. Between July 2004 and January 2005, high mortalities ( up to 80-100% ) were frequently encountered in postlarvae of Macrobrachium rosenbergii in southern Taiwan. Based on the pathological and molecular studies, confirmed the causative agent to be IHHNV. This was the first report concerning natural infection of IHHNV in M. rosenbergii. In further study, we sampled M. rosenbergii from 70 farms including the hatchery and the grow-out farms for epidemiological studies. The postlarvae showing low hatching rate, and sub-adults and adults having signs of soft-shelled, swimming to pond side, lethargy and death were collected. Histological features of IHHNV infection were the presence of eosinophilic intranuclear inclusion bodies ( 22/70;31.4% ) in visceral organs, especially the tubular epithelial cells of hepatopancreas ( 11/22;50.0% ). Using PCR for the detection of IHHNV, the expected 389-bp products were obtained with a set of degenerated primer targeting partial nonstructural protein gene for IHHNV, and 36 farms showed positive reaction ( 36/70;51.4% ). Using the DNASTAR software to analyze protein amino acid sequences, our isolates could be further divided into 4 clusters ( I to IV ). Their genetic variations were more than 0.8% between the different clusters, but most of the strains ( 21/36 ) were belonged to cluster II, identical to American ( AF273215 ), Ecuador ( AY362548 ) and Taiwan A and C ( AY355306 and AY355308 ) strains. Cluster IV (1/36) contained one strain, identical to Taiwan B ( AY355307 ) and Thailand strains ( AY362547 and AY102034 ). Both cluster I ( 7/36 ) and cluster III ( 7/36 ) had no identical sequences deposited in NCBI.
| Identifer | oai:union.ndltd.org:TW/095NPUS5541003 |
| Date | January 2007 |
| Creators | Shih-Ping Lo, 羅世秉 |
| Contributors | Shinn-Shyong Tsai, 蔡信雄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
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