Pokerus is a virus for your Pokemon, so you're right. But it's a GOOD virus, at least for a little bit. When the pokemon with pokerus levels up, the stats go up higher than normal. If you check SUMMARY in your party, you know it has pokerus if it says "Pkrs" for status instead of "PAR, PSN, SLP, BRN, FRZ, or FNT (fainted)". Pokerus spreads to other pokemon in your party or your box if it stays long enough. To make it go away, take it to a pokemon center and heal it. It'll either go away or Nurse Joy will say, "I'm sorry. Your (pokemon) has been infected with Pokerus." Remember: To get Pokerus, you either have to hack or be EXTREMELY lucky. Remember: I think it can mess up your save file if it stays too long. You're welcome