Our cats have advocate flea treatment monthly, and to my knowledge have never had fleas. They have droncit every three months. But one poor cat keeps getting threadworms! They do both roam outside everyday and catch and eat rodents of all sorts, but the vet told me that the droncit should prevent them getting threadworms. Obviously not...the cat that has it only had the droncit two months ago.
What should I try? I'm off to the vets tomorrow to ask, but glad of anyone's advice.