碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 102 / Iridovirus infection in Taiwan grouper have been classified into two genera: Megalocytivirus (TGIV, grouper irridovirus of Taiwan) and Ranavirus (GIV, grouper irridovirus). To explore the probable interaction between these two iridovirus co-exist in grouper, we had separated the two irridovirus origins from orange-spotted grouper into two groups: (i) TGIV high dose and GIV low dose (T+g), and (ii) TGIV high dose and GIV high dose (T+G). TGIV is restricted to replicate in-vitro and thus it was obtained from grouper larvae for propagation. Recently the obtained grouper larvae are GIV-carrier therefore we used GIV group only as positive control in this study. In fish challenge experiment, the cumulative percent mortality was 100% in GIV group, and 85% and 3% in T+G and T+g group, respectively. We had compared the infected fish spleen, head kidney, and heart with the control group to analyze organ coefficient (ratio of organ to body weight), and found that there was only significant differences in spleen enlargement. GIV- infected fish appeared spleen enlargement in early stage but observed one week after infection in both T+G- and T+g- infected fish. The spleen of T+g- infected fish is bigger than T+G group. In addition, real time PCR was used to analyze the viral loads in spleen, head kidney, heart, gill, kidney, intestine, liver and muscle in each group of fish. The results revealed high viral loads were detected in spleen, intestine, liver and head kidney in GIV group where it can reach up to 4 #westeur024# 107 copies or above at 7th day. For T+g group, the TGIV loads in each organ was maintained at 106 copies in 1st, 7th and 11th day and decreased to 103 at 15th day. GIV was maintained at 103 ~104 copies in all sampling days, no proliferation was observed. For T + G group, the TGIV loads will increase over time in each organ; at 7th day it reach to 8.5 #westeur024# 106 copies in spleen, the other organs also reach to the highest value, 106 ~ 107 copies; and the viral loads was decline to 104 ~ 105 copies at 15th day. While GIV loads trends had similar with TGIV as it reached 3.8 #westeur024# 106 copies in spleen at 7th day. Head kidney, heart and kidney were reached to 105 copies above. At 11th day, the high GIV loads was detected in each organ where it reached up to 106~107 copies. At 15th day, the GIV load was dropped to about 104~106 copies but decline less than TGIV. For GIV-infected group, the head kidney expressed tissue necrosis whereas the mast cell was observed in T+G group at 7th, 11th and 15th days. Ultimately, major capsid protein (MCP), for GIV and TGIV, respectively was designed to explore the in-situ hybridization staining and the results revealed tissues necrosis near in head kidney and spleen area in each experimental group had positive reaction. The above results indicated the GIV caused acute infection and leads to high mortality whereas the progression of TGIV infection is slow. This had predicted that these two virus co-infected fish may interfere each other and the fish death may cause by GIV proliferation.
keywords：TGIV、GIV、coinfection。
| Identifer | oai:union.ndltd.org:TW/102NTOU5086027 |
| Date | January 2014 |
| Creators | Huang,Ching-Ting, 黃勁婷 |
| Contributors | Chou, Hsin-Yiu, 周信佑 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 47 |
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