I might be worried about SIBO, bacterial overgrowth, which is in the intestines and often not giardia. I would try a round of metronidazole to see if it helps, since it should help with giardia and also SIBO. Tylan is a safer long term treatment for this if needed, but for an acute situation, metro works well (it is neuro toxic if used in the long term).
If the blood results show that liver and kidney function are good, you guys should be okay. Still might be a good idea to add something like Country Life's "Liver Support Factors".