I don't deworm my frogs unless they are showing symptoms of illness that can be tied to internal parasites. My philosophy is that it is best not to mess with nature unnecessarily, as more research is done we sometimes learn that organisms once considered to be parasites may actually be a benefit to the digestive process (i.e. pinworms in some reptiles). Our animals and their gut flora have evolved together over many thousands of years, and unless there is a clear sign of an imbalance harming the frog I think that intervening is riskier than leaving them alone.