How can you get pokerus?

You can get pokerus by battling an infected Pokemon in the wild.How you know the Pokemon has pokerus is simple (for this i recomend you using a very high level Pokemon you want to get pokerus,at least level 70,in the first slot of your party).Go everywhere where there is grass & water and walk through all of it in Sinnoh,kill all of the Pokemon you battle (Belive me this is very hard) then when you battle a pokerus infected Pokemon,when you hit it and its a low level, it wont die.I think that the pokerus spreads to your Pokemon when you battle it,and it wears off in 24 hours if you don't put it in a PC box