It’s known that some infectious diseases alter the behaviour of their victims. One example is Toxoplasma gondii which can infect many mammals, but reproduces predominantly inside cats. When T. gondii reproduces, it produces oocysts that are excreted in cat droppings and can stay inactive for months in contaminated water or soil. If an oocyst is eaten by a rat, the infection appears to change the rat’s behaviour so that it seems to become less afraid of cats. This makes the rat more likely to be eaten by a cat, giving T. gondii a new chance to reproduce.
This graduate thesis  looked at how infection with Israli Acute Paralysis Virus (IAPV) might change honey bee behaviour. Some of the changes appear to be protective. Infected bees interact less with other bees in the hive, do less food-sharing and start foraging earlier, changes in behaviour which make it less likely for hive-mates to become infected.
But this could be part of a cunning plan. For though infected bees remove themselves from their hives earlier, they seem to be more welcome in hives they drift to, possibly because the virus has an effect on how they smell different. So, rather than protecting their own hive, the infected bees’ behaviour could spread disease more rapidly to other hives.
 Geffre, Amy C., “Infiltrating the hive mind: Immune and viral effects on behavior of the honey bee (Apis mellifera)” (2018). Graduate Theses and Dissertations. 16355.
A graduate thesis is a report of research carried out by a student in the pursuit of a qualification such as a Masters degree or a PhD. It is an individual effort, usually done with very limited resources, and not subject to external peer-review (unless later published in a journal).