That's fascinating Jack. I did read somewhere that Third World populations with a high rate of intestinal worms (especially in children) had far fewer allergies such as asthma, eczema etc. than our wormless folk in the West. This must be linked somehow to the release of cannabinoids into the host.

W Africans have many types of parasitic worms, and while they may release cannbis-like chemicals, they also damage the intestinal wall when they hook in to secure their position and feed. My husband had to be admitted to hospital when he first arrived in UK as these old wounds had become inflamed and he had an 'acute abdomen'.
Luckily, he hasn't developed allergies in spite of being worm-free for years now.
If he does, perhaps I'll roll him a joint!