In Pokemon Clear and Iron, very rarely, a pokemon can have Pokerus. This is different from previous games, however. 1. * You can actually tell if a pokemon has pokerus, because, when you release it a strange noise happens after its cry, as well as a swirly effect. 2. * The Pokemon with pokerus is harder to get it to pass on to other pokemon. 3. * It is harder to cure as well. 4. * Pokerus comes in several varieties. 5. * The HP variety 6. * The HP variety increases growth of HP. 7. * The Atk variety 8. * The Atk variety increases growth of Atk and Sp Atk. 9. * The Def variety 10. * The Def variety increases growth of Def and Sp Def. 11. * The Spd variety 12. * The Spd variety increases growth of Spd. 13. * The XP variety 14.