From: Superboy #140 (July 1967)
That morning, a frisky Krypto physically pulls Clark Kent out of bed so Superboy will play with him. You know. Just another day of crime-fighting trolling underwater alpha predators.
While they frolic about, they come upon a Kryptonian capsule which contains, as we find out when Superboy brings it to the surface, a stash of deadly viruses. Don't tell me Krypton didn't deserve its fate, what with all the crap they routinely threw at the rest of the universe. And one of those viruses was quick-to-boil Space Rabies!
On Krypton, the disease is slightly different than on Earth. For one thing, it is deadly to people. And it makes dogs grow in size like so:
In other words, it turns Krypto into New52 Krypto. The super-dog immediately turns on his master and tries to bite him, and to divert his attention, Superboy does the only sane thing.
In addition to craving supple Kryptonian flesh and rock-hard feline effigies, Krypto also can't resist vehicles. They drive him madder!
The military takes it upon itself to put the beast down, but Superboy pleads for an hour to find his own solution before they kill his dog, but his only plan is to "talk him down", which of course, doesn't work. BITE!
Clark only just manages to get home and falls sick. Meanwhile, the military plans to end our long national nightmare, but Krypto is saved by a combination of poor marksmanship and, get this, the rabies simply WEARING OFF.
Krypto goes home where he finds his dying master, and Clark tells him to go fetch the rest of the virus. But why? Krypto does so, and Superboy asks him to expose him to the Blue Plague. Somehow, Epidemiologist Krypto knows dogs are immune to that particular disease, so in his mind, he's just committing assisted suicide. But...
Kryptonian viruses are so nasty, they like to kill each other, leaving your rested and refreshed. All that's left is to throw the damn things into the sun. Hopefully, Superboy has better aim than his Kryptonian forebears.
Comments
Also, everyone is 100% sure of the effects of diseases in this, aren't they? "I know exactly how Kryptonian rabies is different from Earth rabies", "this diseases will definitely affect us even though we have superpowers on Earth", "if I get bit by a rabies infected dog I will definitely die", "this Blue Plague definitely doesn't affect dogs", "this Blue Plague definitely doesn't affect humans", "this Blue Plague somehow cures rabies but won't actually give me the Blue Plague". Considering that Clark didn't realise the rabies would simply wear off, maybe be a bit less casual with exposing everyone to this germs, eh?