Leopard Gecko

Hi DP,
Yes, wild crickets, as well as grasshoppers, are very often hosts for certain species of tapeworm. Dogs and cats most often get them from ingesting fleas, another host.

I think they can catch diseases or things to make our pets sick.

I have worked with reptiles for awhile now and it is true that anything you feed your reptile/ pet from the wild has the risks of worms, digestibility problems. Etc. One of the major problems is you don't know where the crickets/ bugs have been.... If they come from an area that has been sprayed for pests, or any other poisons, you have the risk of poising your reptile... So just go to your local pet store get some crickets, meal worms, Phoenix worms, wax worms, and you can also feed them fruit baby food 2x a week, fruits and vegetables... But have fun and remember to make sure he has a good humidity hut or some way to get moist... Have fun ...
Petguy!

Yes, wild crickets, or anything else can be dangerous to your pet. And they can get worms from the crickets being in contact with grass that can have worm eggs on them.