Matt, I don't think you have a firm understanding of how immunity works. It's not some numeric slider that says "YEP, WE'RE 85% IMMUNE TO INFECTIONS. WOOHOO, JUST A LITTLE MORE AND WE'RE MAXED!". You're dealing with things on a molecular and biological level... aka: genetics, and the concept of survival of the fittest. You might be able to strengthen your immune systems response in some regards, but you're not going to make yourself immune to everything out there just by exposing yourself to them in small amounts (and how you think you're going to measure that I'd like to know because you wouldn't).. particularly if your genetic makeup is pre-dispositioned to being weak against certain types of infections/parasites/diseases. These frogs have developed genetic traits that reflect immunity to their natural environment in AFRICA over thousands of years.... not several years, and certainly nothing over here that is native to this environment. Introduce them to a disease that their body has no way of coping with and you end up with massive fatalities... kind of like what happened when we brought smallpox over to the Native Americans and it completely wiped them out. It's the exact same reason why Americans aren't supposed to drink Mexico's water. If you let that water into our public drinking system there would be an epidemic, and people would be getting sick everywhere. Mexicans are immune because they're a branch from the Mayans, which have lived there and dealt with that environment for several thousand years... SAME THING as our frogs that we keep. Bring them over here and subject them to our diseases and I assure you they won't last long, even if they're allowed to build their immune system up. It just isn't that fast no matter how bad you want it to be. You MIGHT get a genetic mutation that formulates from a disease, but the chances of getting that are 1 in billions, so I hope you're feeling lucky. That's literally the only reason why Mexicans are still alive... traits that have aided towards those who DID survive towards the next generation; which may or may not strengthen those traits when passing them on.... that's for the next generation to see if it pans out. You have ONE generation of frog. You're not going to build a super immune frog. Not going to happen.