One could do an electrical probe, I suppose. They seem to move away from the shock, and one could do that to 'scan' for lurkers. Or maybe praziquantel is sufficient, or maybe Miracle-Mineral-Supplement ..
I shocked my goodies pretty good once [roof of mouth to top of head], when I had the power level set a little higher higher for going from hand to hand, and I 'saw the light' so to speak [~40-50V]. A side effect was that I did experience noticeable enhanced clarity [after the day or so of recovery]..Maybe I shook something loose?
>or worse yet, they are on the street where we walk and we pick them up and take them into our home
In many countries, its shoes off at the door...
>My son in in a preschool where everyone is potty trained. Do you think the class is at risk for the dwarf Tapeworm you are talking about?
Possibly, I guess you just have to look at the other children and their parents.
How can I help prevent that? According to the link above, one can use Praziquantel; I have seen it available at specialty pet stores. Isn't it nice how well we treat our pets? That's another one of those 'inconsistencies'.