Hi I have three questions what is pokerus,what is so good about it ,and..

Pokerus is this so called "disease" or whatever that attaches to your Pokemon and helps them get better experience, so I wouldn't call it a bad disease, it can spread to your other Pokemon if it's in your party, but can't get it more than once. Shiny Pokemon are just cool cause they are, like a black charizard if you go to http://www.pokemonelite2000.com/index.html you can see them all shiny

The pokerus is a Pokemon virus that never stops increasing your pokemon's stats.(Increases only the Pokemon that have the pokerus).It is good because it raises you're sstats like attack, defense, speed, special attack, and special defense. People like shiny Pokemon because alot of them look very neat with a different color, and it is rare to get a shiny Pokemon, and I mean really really really rare to get one, but you can get shiny Pokemon using cheats from an action replay or a gameshark.

Sorry I don't know the answer to your first part of your question but I do know the second part,because they have stars around it when ever you find one,also it'd a diffrent color.

Pokerus is like a virus that spreads to your pokemon. It causes your pokemon's stats to increase. That's why it's so good. Shiny Pokemon are cool because they're very rare to find. It's like a 1/8100 chance of finding one. So if you do find one, then you are very lucky.

^_^