Unique physicochemical properties of the occluded penaeid shrimp baculoviruses and their use in diagnosis of infections

Occlusion bodies in wet mounts of phloxine-stained tissue squashes and paraffin sections of penaeid shrimp infected with Baculovirus penaei and Penaeus monodon-type baculovirus fluoresced when viewed with an epifluorescent microscope. Inclusions of hepatopancreatic parvo-like virus, infectious hypodermal and hematopoietic necrosis virus, and Autographa californica nuclear polyhedrosis virus did not fluoresce. The use of phloxine stain (alone or as a component of an eosin preparation) and fluorescent microscopy may enhance detection of low-grade infections by these disease-causing agents.