Honestly, this isn't surprising to me. This sort of thing has existed for about as long as life itself. For example, there is a fungus that, once it infects an ant, will work it's way into the ants brain and nervous system. As soon as it is entrenched within, it will cause the ant to seek out other ants and cause the ant to have an urge to climb to a high point near by. Once in position, a stalk of the fungus will grow out of the back of the ants head and release a spray of spores that rain down on any other ants in the area. Then, the cycle repeats.
This fungus has been around for so long that many of the ant colonies that are confronted with it actually know how to deal with it. They'll often send another ant to carry the infected one to a location far from the colony. (which often ends up being a suicidal "mission")
However, I will say that I'm glad those researchers were able to identify and single out the aspect of the virus that activates the gene that causes that behavior in the gypsy months. Discoveries like this are a big step towards figuring out how to, say, shut off cancer cells or cure a plethora of other genetic diseases.
GO SCIENCE!!