Hookworms are very possible whether caused from your own viv conditions or from where the frogs came from. First off they are decently easy for a vet to spot and panacur isnt that hard to find but I would suggest sending a fecal to DR David Frye. Its not that pricey and he will give you a definite answer on whether or not you have hookworks, lungworms, coccidia and all the other nasties. He will also set you up with the treatment needed. Usually its just a simple dusting of the food once a week for 8 weeks then you test again.
Keep in mind if you have a higher load of hookworms you will need to break down the viv and start over after sterilizing it to get rid of them all together otherwise your just treating the frogs in a contaminated viv. This just causes them to become recontaminated and over time there is talk of excessive treatments becoming immune,
Your best bet is to quarantine your frogs when you get them in tubs or anything that is easily cleaned and sterilized so you can have fecals done before they go into a viv and contaminate it.

Michael