Re: If memes are real do they necessarily have to have a human origin?

I assume you're referring to the concept of a "meme" introduced by Richard Dawkins in The Selfish Gene, Oxford University Press, 1976. Dawkins calls the meme a new kind of replicator, a "unit of cultural transmission, or a unit of imitation," and gives as examples tunes, ideas, catch-phrases, and clothes fashions. The idea is that the mass of humanity is a sort of culture medium in which some behavior patterns reproduce, that is, create copies of themselves.

Humans aren't the only culture medium in which memes propagate. Any bunch of organisms whose behavior is influenced by the behavior of organisms around them can support memes. If you show a chipanzee a new way to crack a nut, and other chimps see him and imitate him, then you have created a meme that reproduces in chimps.

So, in answer to the question in your subject line, memes are real, they can propagate in non-human species, and they don't have to be created by humans.

You also ask, "Could non-human factors be operating on human conciousness for their own benefit?" Perilous vagueness loads the phrases "non-human factors" and "for their own benefit". If by non-human factors you mean space aliens, it's not impossible, but unlikely to such an extreme as not to be worth contemplating. On the other hand, if you're referring to politicians sowing propagating thought patterns conducive to their re-election, then it's definitely true.

An especially complex human-based meme that stresses the question of "for whose benefit" is the manufacture and ingestion of ethanol. Lost in antiquity is some human's discovery that if you mush up certain things, let the mush rot, and drink it, it makes you stupid. Astonishingly, this meme has propagated so successfully in our species that every day, in every country of the globe, people participate in the ritual of mush, rot, drink. Why is this meme so successful? Not because it was crafted by space aliens. Not because it benefits the participating humans. It just happens to work: it replicates successfully.