Well, it is not a worm... it is a caterpillar... keep it long enough and perhaps a becomes a beautiful butterfly
On the more serious side, I guess something like 5.000 miles and more miles will be offered. I wouldn't even pursue this, it should not happen but it can happen anywhere, anytime. As long as it is not a highly-toxic-one-bite-and-you-drop-dead spider or somethign which would give me a serious food poisoning, I would just forget about it and move on.