1983 Volume 17 Issue 4 Pages 263-268
In the previous paper (1981), this author indicated that the most characteristic cytological change of this disease producing high mortality of kuruma shrimp larvae and postlarvae was hypertrophied nuclei resulting in chromatolysis of the affected mid-gut gland epitherial cells. SANO et al. (1981) also pointed out the hypertrophy of affected nuclei as the characteristic symptom of this disease, demonstrated Baculoviral infection in such hypertrophied nuclei and the epizootic in the intensive culture farm of kuruma shrimp.
In the present study, the author examined to diagnose this epizootic by detecting hypertrophied nuclei in squash and stained preparations of the affected mid-gut gland, or in squash unstained preparations under central illumination, dark field illumination, phase contrast and interference microscope. These results obtained were as follows;
1. Squash and stained preparations: hypertrophied nuclei were clearly seen due to probably increased DNA.
2. Squash unstained preparations: 1) under central illumination hypertrophied nuclei were observed as if containing many granules, but not clear. 2) under dark field illumination hypertrophied nuclei were clearly seen in white. 3) under phase contrast a lot of rod-like particles (about 1μam length) were often observed in the hypertrophied nuclei. These rod-like particles were arranged almost vertically to the nuclear membrane at the marginal area, and also they scattered throughout in the nuclei, or sometimes they lined up parallely to each other. 4) under interference surface of the hypertrophied nuclei was somewhat rough.
Three out of these methods, squash and stained preparations, squash unstained preparations under dark field illumination and phase contrast microscope seemed to be available as presumptive diagnostic techniques for Baculoviral Mid-Gut Gland Necrosis of kuruma shrimp.