I am not an expert but went thru the same questioning process as you some four months ago. This is what I learnt:
1) Zappers and freq gens might not reach organs! They are more effective for electrification of the blood and the not so deep areas of the body.
There is a highly respected person on the Rife forum called Newport that advised me i would need a frq gen or rife machine with 4 connections to have any effect at all on my strongyloides. hence I bought a Zapper Digital megahertz +. it was about $250 ... not cheap, but alot cheaper than a RIFE machine. This will enable you to dial up those frequencies that mendomaid gave you for liver flukes.
Its difficult to know whether its helped with the strongyloides but I have used it quite successfully as a diagnostic tool for identification of parasites, when used with kineisiology.