The idea that thoughts, or even words and numbers can be a virus are based on Dawkins notion of memes. Viruses exist in a state that is difficult to say that they are alive or not (by our definition of life), similarly AI or even alien sentience is difficult to define. Can we know if a dog is sentient, or a bird, or ant? and if they are, what is their sentience?

Basically, if a number like 23 can be a virus, ie. once you are aware of the number 23, you will see it everywhere and it will hold significance, is the number 23 alive?