as already mentioned, allergies can be more common in blues because of the undisciplined breeding behind them.
but as far as parvo, coccidia, and giardia... those are not conditions related to the color of your dog. sounds like your home is contaminated with several bugs or a bad water source. OR you allow her to socialize with other dogs that are infected.
you need to treat her and also decontaminate everything.
~ jo and Gotti Boi (aka Thunder Thighs, aka Jughead, aka The Doo Doo Monster, aka Sexual Chocolate, aka Mister Smiley, aka Sofa King)