While searching for other effective anti-parasitic herbs I've come across Neem and looked for it here. Found this:
"When you hit the bottom layer you get a mix of Buski protecting the T.Serialis. It gets busy down there. The Psychic attachment (one day I will spill the beans on that) actually directs these critters to surround and protect the crystalline structure.
You can use Coconut Oil and Neem to calm them for a few hours...but there is NOTHING like Vervaine."
So, still Vervain is pretty much the best out there.
Re: cannabis, I've dowsed it asking whether it's more effective than Vervain and got a no. But then asking the same question for Vervain vs Cannabis and got a no as well.
Apparently, they are both effective but in their own manner, i.e. used for different purposes. Cannabis tincture has an anti-parasitic effect too (dowsing), but for which pathogens I dunno.