Abstract
Inactivation of BMN virus by ultraviolet (U.V.) irradiation, sunlight exposure, heating and drying treatment was investigated by means of the infection method of the author using larval and post-larval kuruma shrimp, Penaeus japonicus. Test shrimp sampled on day 4 after waterborne inoculation were examined for nuclear hypertrophy of the mid-gut gland epithelial cells in fresh squash preparations under the dark field microscope. The results obtained are summarized as follows;
U.V. irradiation (15 W U.V. lamp, 30cm in distance) : BMN virus was inactivated within 20 minutes post-irradiation. The U.V. dosage during this period was measured to 4.1×105μW·sec/cm2.
Summer sunlight exposure : The virus was inactivated within 3 hours post-exposure at about 30°C.
Heating : The virus was inactivated within 120 minutes at 45°C, 30 minutes at 50 and 55°C, 5 minutes at 60°C.
Drying : The virus absorbed in a filter paper was inactivated within 1.5 hours postdrying at about 30°C.
