碩士 / 國立臺灣大學 / 漁業科學研究所 / 85 / Freshwater prawns (Macrobranchium rosenbergii) in southern
Taiwan exhibited idiopathic muscle necrosis in abdominal
segments. It was found that this symdrome probably occurred
throughtout all the year and in most cases took place within ten
days after moving post-larvae into outdoor ponds during July to
December. Non-transparent muscle opacity was a commonly observed
feature of the muscle in abdominal segment 2-6. The common
phenomena were the progressively weakening of their swimming
ability and inclining to stay on grasses or the walls of ponds.
Their mass larval mortalities were probably more than 50%.
The quantity of the four water factors (ammonia, nitrate, COD,
gross bacteria) in the infective ponds was not more than that of
the non-infective ponds. Further-more, we never found epibiotic
organisms during microscopic observation in both healthy and
muscle necrosis prawns. In paraffin sections, we found that
muscle fibres had displayed progressive segmental myofibre
degeneration and necrobiotic myopathy, including eosinophilia or
hyalinization, fragmentation, flocculation, granulation and
haemocyte infiltra-tion.The prominent shrinkage of the myofibres
caused by progressive loss of myofibre parenchyma (myofibrils
and saroplasm) led to diffuse areas of myofibre disorganization,
associated with numerous single, rows, aggregations and sheets
of hyperchromatic myonuclei, often centrally or eccentrically
placed (nuclear internalization) and pyknotic nuclei.Yet, no
bacteria, fungi or internal parasites were discovered in any
necrosis muscle. Our electron microscope examination showed
that there were mass parvovirus-like particles existing in
infected muscle cytoplasm. Their sizes were about 18-20 nm,
without any envelop. This virus was able to form large
,icosahedral, basophilic, feulgen positive, intranucliar
inclusion body. By means of pyronin methylgreen stain, we could
clearly distinguish these light-green inclusion bodies from
purple muscle nuclei. In final analysis, we conclude that
this virus is different form any crustacean virus that has ever
been published. For this very reason, we temporally call it
Macrobranchium Muscle Virus (MMV)─the first pathogenic virus
found in the freshwater prawns (Macrobranchium rosenbergii).
| Identifer | oai:union.ndltd.org:TW/085NTU00451002 |
| Creators | Tung, Che-Huang, 董哲煌 |
| Contributors | Chen Shiu-Nan, Kuo Ching-Ming, 陳秀男, 郭欽明 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 73 |
Page generated in 1.0214 seconds