A prion that infected people rapidly, through saliva-to-blood contact, and had similar symptoms to rabies without the rapid death would be very similar to traditional zombie lore.
The protein would probably also have to effect the olfactory glands, creating an attraction to uninfected humans.
It's hard to tell if you've been sincerely misled or if this is just a joke. Either way, though, it's not really plausible. The closest thing to a "zombie" that we get in nature are ants that are infected by Ophiocordyceps unilateralis. This fungus causes the infected ants to crawl to a fungus-friendly location on a leaf and remain there until the fungus kills it and produces more spores.
In the I Am Legend novella (a big contributor to modern zombie), the infected are more like vampires and retain their intelligence. The book is notable for the primary theme it introduces, the otherness of the zombies (in earlier depictions they are largely undead plot devices)
Romero's Night of the Living Dead also plays with the otherness theme, but the dead are numb and more ghoulish than vampiric.
28 Days Later finally has something I would agree is rabies inspired. It probably contributed to the frantic behavior of zombies in several recent movies.
"The roots of the vampire myth stretch back nearly as far. Tales of vampire-like creatures, formerly dead humans who return to suck the blood of the living, date to at least the Greeks, before rumors of their profusion in Eastern Europe drifted westward to capture the popular imagination during the 1700s.
In its original imagining, though, the premodern vampire differed from today's in one crucial respect: His condition wasn't contagious. Vampires were the dead, returned to life; they could kill and did so with abandon. But their nocturnal depredations seldom served to create more of themselves.
All that changed in mid-19th century England—at the very moment when contagion was first becoming understood and when public alarm about rabies was at its historical apex. Despite the fact that Britons were far more likely to die from murder (let alone cholera) than from rabies, tales of fatal cases filled the newspapers during the 1830s. This, too, was when the lurid sexual dimension of rabies infection came to the fore, as medical reports began to stress the hypersexual behavior of some end-stage rabies patients. Dubious veterinary thinkers spread a theory that dogs could acquire rabies spontaneously as a result of forced celibacy.
Thus did rabies embody the two dark themes—fatal disease and carnal abandon—that underlay the burgeoning tradition of English horror tales. Britain's first popular vampire story was published in 1819 by John Polidori, formerly Lord Byron's personal physician. The sensation it caused was due largely to the fact that its vampire, a self-involved, aristocratic Lothario, distinctly resembled the author's erstwhile employer."
