I just had a customer who purchased an 8 week old pup from me over the weekend call to let me know their pup had a Vet appointment yesterday, and he tested positive for coccidiosis

I'm reasonably sure it came from my kennels, because the other day I had one of my then three remaining pups become lethargic and refused to eat for a day. She miraculously recovered when I offered her ground meat, so I thought it was nothing more than a stomach upset. Guess not.
So ... what is coccidiosis? An intestinal bug??? If I'm remembering correctly, its treated with Albon ... can I treat it myself or does this need to be made into an $$$$$ Vet visit for the two remaining pups? Also, how can I get it out of the environment? I bleach my home and yard quite often (once weekly for the yard, twice for the puppy area in my home). If the bleach hasn't killed it, is there anything that will?
Thanks for any help!