Usually you just keep it in your storage for a long time.
pokerus is a virus thank is good for pokemon. it raises stats and hp.
Pokerus happens at random, it is about as rare a finding a shiny pokemon.
It means that that certain Pokemon had pokerus and is no longer able to get pokerus again
like in any game go to your Pokemon party and check their summary. and if you a symbol that is pink and says "pkrs," that means your pokemon has pokerus.
Pokerus is a virus that infects your Pokemon. It catches this virus from a wild Pokemon that also has pokerus. If you keep a Pokemon with pokerus in you party, your other party members will also get this virus. However, this is a good virus as it doubles the EVs you earn from battles. Your Pokemon will eventually lose pokerus in four days but you can preserve it by keepin it in PC and allowing your other pokemons catching it.
There is no certain number, It's just a rare occurance.
http://www.neoseeker.com/Games/action_replay/
As far as i know, definetly in Diamond,Pearl,Platinum,Heartgold,and Soulsilver
http://www.neoseeker.com/Games/action_replay/
um e leveling
Pokerus might be a diseased disease and it might effect all of your Pokemon, that's good! It makes all of your Pokemon stronger than it was before! It just randomly pops up on your Pokemon!
Depending on whether or not u are using a official or patched Pokemon platinum the pokerus code changes. Also you can check youtube for further details..... www.youtube.com