CBC Test; normal after 4 yrs infected Dr. Holodniy,A friend tested HIV+ 4 years ago. He has chosen to abstain from taking any medications (due to personal reasons). Recently, he took a CBC test and everything showed up as normal. Why is that? Shouldn't his WBC count be a little low?
Encountering a Shiny Legendary or a random shiny Tentacool have the same rate of 1 in 4,096. However in the wild the chance of a Shiny Pokemon with Pokerus is 1 in 178956971. Your Latias is very rare as it is Shiny but also has Pokerus. However the Latias probably had Pokerus infected onto it via another Pokemon. There is also a possibility it was hacked too.
If you have a Pokemon in your party with Pokerus and different Pokemon without Pokerus it can spread onto the Pokemon without Pokerus. The Latias is definitely very rare if the person who traded it to you caught it in the wild, even if he spread Pokerus to the Latias it is still rare. Or the person could've just hacked the Latias. Hope I helped!