The Multiplication Regions and Interaction of Acute and Chronic Bee-paralysis Viruses in Adult Honey Bees

Serological and infectivity tests showed that acute bee-paralysis virus accumulated in the heads of acutely paralysed bees, especially in the hypopharyngeal glands, and that much virus also occurred in the brain, where particles resembling acute bee-paralysis virus were made visible by electron microscopy. Similar tests showed that chronic bee-paralysis virus was concentrated in the brains of chronically paralysed bees. Electron microscopy of the brains showed particles resembling chronic bee-paralysis virus but these may have been synaptic vesicles or sectioned microtubules, since similar particles were also seen in the brains of apparently healthy bees. These particles also resembled particles that were seen in sections of pellets of purified chronic bee-paralysis virus, and that were electron-transparent in the centre.

Many bees injected with acute bee-paralysis virus and kept at 35° remained apparently healthy though they contained at least as much virus as bees injected with acute bee-paralysis virus and kept at 30°, all of which died of acute paralysis. Conversely, chronic bee-paralysis virus multiplied more at 30° than at 35°, though it killed bees more slowly at the lower temperature. When acute bee-paralysis virus and chronic bee-paralysis virus were injected together into single bees, acute bee-paralysis virus multiplication was depressed at 35° and chronic bee-paralysis virus multiplication was depressed at 30°.