I am curious what city this WalMart is in and have you heard any more from your friend what it could have been. It could be other things of course however your theory that bird flue could be transmitted in products/packaging is a good consideration.
I have oregano pearls...are those the same as the oil you are describing using?? My anti-viral of choice, too, is olive leaf. I read somewhere that buffing up the immune system with Vitamin C is effective, but is there any other specific supplements you are suggesting specifically for Avian Flu if it mutates?
ps. do you know of a good source for bulk olive leaf? In the past I have used the capsules only, and they are quality ones, but I have a capper and could do it myself if it is more economical...