I dont know if links are allowed but this is what you are talking about ,right. Congrats though ^__^
Although this is not something new, I have decided to make a page about it. Below is a screenshot of my infected Pokemon, Salamance, with the Pokerus. The small purple note in the bottomleft corner indicates such.
Getting the Pokerus is random. In Gold and Silver, you had a 1 in 21845 chance of this happening. The odds of this happening have probably increased in RuSa. The sound of a 'virus' may seem like it will harm your Pokemon. It will actually not. It will increase your Effort Value by 1.5. What does that mean? In simple terms, your Pokemon will get alot stronger, faster. This will not make them stronger than normal. It just means they will reach higher stats without having to train as much. They will still get the same EXP however.
FAQ:
Question: How do I get the Pokerus?
Answer: It is random. To get it, you will encounter a wild Pokemon with it, who will then give it to you, however you will not know that they have it. Nurse Joy will inform you if you get it. There are no areas that have a higher chance of finding it.
Question: Where do I get the Pokerus?
Answer: As I said before, there is no set location for the Pokerus. Any Pokemon in any location may have it. Think of find the Pokerus as finding a shiney Pokemon. It can happen at any time, just do not run away from battles. If you run away, you will not get the virus. So in conclusion, the Pokerus is entirely random.
Question: How long does this last?
Answer: On midnight of the 4th day, the virus will not be able to spread anymore. Meaning that they will still have its effects, but they cannot spread it. Any Pokemon inside a box will still have it forever.
Question: How can you spread the Pok?rus?
Answer: First have a Pokemon on your team with it. Spreading does not occur in boxes. Then go out to battle some wild Pokemon. If you KO the Pokemon, meaning you do not run away, there will be a 1/3 chance that it will be spread to the Pokemon next to it. Making a level also helps to increase the chance that it will spread.
Question: Can I breed the Pok?rus? My egg hatched with it!
Answer: You cannot breed the Pok?rus. Having a parent with the virus will not give it to the kid. The reason you egg hatched with it is because it was spread like any other way. As an egg, it will not say if it has the virus or not, however it can get it. You just will not know until it hatches.
If anyone has any questions on this virus, email me about it. Seeing as how I have had it for over 2 years, I have had my share of tests on it.