Abstract
This paper describes the survival of BMNV in tissues of frozen or freeze-dried infected post-larval kuruma shrimp, Penaeus japonicus, and in sea water at different temperatures.Larval and post-larval kuruma shrimp were used as test animals for infectivity trials. Test animals sampled on day 4 after water-borne inoculation were examined for nuclear hypertrophy of the mid-gut gland epithelial cells in fresh squash preparations under the dark field microscope.
BMNV in frozen tissues did not tolerate to 5 years storage if stored at -20°C, whereas it survived more than 7 years at high levels of infectivity if stored at -80°C. The virus in freeze-dried tissues tolerated to 7 year storage at 4°C, but having 99.9% loss of infectivity compared to that of the virus in frozen tissues stored at -80°C.
BMNV in sea water tended to reduce its survival period with storage temperature rising, and was inactivated within 4 days at 30⪚C, 7 days at 25°C, 12 days at 20°C and 20 days at 15°C.
