What is Pokerus?
Pokerus is a type of virus or microscopic organism that may infect a Pokemon, or pocket monster in a “Pokemon” computer game. But despite its association to a viral infection, it is actually a good idea for a Pokemon to get infected with this virus since it will cause doubling of the effort values from battling with other Pokemons, whether they are wild or bred.

For gamers who are training their own Pokemons, it is said that being infected with the Pokerus is a great thing to happen since it will double up a gamers statistics after a battle. But being infected is one thing, getting infected with this particular virus is a whole different story. For some, it is just not easy to get infected with the Pokerus. For most people, the easiest way to get the virus is to find some other Pokemons who have it and try to get close to it so your own Pokemon will be infected. Others suggest that fighting and battling with a wild Pokemon is the best way to get the Pokerus. If your own Pokemon is able to beat a wild monster then you will have the chance to randomly catch the Pokerus. Another option to possibly get infected is to visit the Pokemon Center often.

But the infection with the Pokerus may only last for two days. So it is advised that once infected, Pokemons must spread it with the others as soon as possible, so they too can experience the benefit of doubling up stats in battling. The only way for the Pokerus to stay longer is to put your own Pokemon in a PC box.

The Pokerus was first introduced in Generation II Pokemon games. The overall concept of infection and doubling of stats on battling more or less remained the same with succeeding generations of the game.