Slugs and Immunity

There are slugs in the water cooler that I drink water from!!Now that I've got that out of the way I can concentrate on the ramifications of this creepy-crawly issue.
While nowhere nearing the shock value of "There are monsters under my bed",this whole episode of slugs(or snails..I'm not entirely sure..are they snails if they don't have a shell?) in my water still astounded me as to how the human body adapts itself to hostile living conditions.NITK hostels is a breeding ground ,among other things, for the degenerate "freaky genius",alien life forms and the odd genius.But slugs in my water cooler was something I was unprepared for.
It is perhaps a testament to the steely resolve and dedication(sic) of the NITKian that they not so much as bat an eyelid when they see slugs in their elixir of life but drink it in a spirit of scientific enquiry.Now,it is my contention that since I've unwittingly consumed this water for so long and managed not to contract explosive diarrhea or sprout tentacles one of the many things I shall owe this place is an immunity to slug-borne diseases.As one of my friends rightly pointed out,slugs are one of the most prolific disease-vectors.
Thank you NITK.Thank you for the antibody!