That's misleading information. Bibarel, nor any other Pokemon for that matter, does not have a higher chance of getting Pokerus. Getting Pokerus is a completely random, albeit, improbable event in Pokemon. I first came across it in the 2nd gen, and it's been pretty much the same ever since.
While a Pokemon infected with the Pokerus remains in your party, there is a chance that everytime you defeat a Pokemon (wild or a trainer's), the virus will spread to one or more of your other Pokemon. Eventually, (after a few days, maybe a week,) the Pokemon will "heal" itself naturally, then the Pokerus is lost.
If the infected Pokemon stays in the PC box, though, the Pokerus will not disappear. This way, you can preserve the Pokerus by storing an infected Pokemon in your box, then when your party Pokemon lose their Pokerus, you can infect them again by withdrawing the infected Pokemon from the PC. It's alright to recycle this method, but you should always have more than one Pokemon with Pokerus in the box at once if you want to make sure that it won't go away entirely.
