Re: Here is a real eye opener for anyone who may be dealing with worms - or a pork tapeworm

Ova/ parasite tests frequently fail. Ova is eggs, a full blown worm would be nagative for Ova unless they find eggs within the worm and test that site.

Tests are often for a specific set of ova/parasites. If they are clueless/negative, then usually they do not recognize the newcomer specimen.