I got kitty almost a year and half ago. I trapped him. He was taken to the vet and given worm medicine etc. Thing is I cannot get rid of them. He has had drontal and strongid. Each time after giving him it and waiting his stool then is negative as if they are gone. Then after a month or so they keep coming back he vomits. What can be done?? If anything. Will a stray forever have worms?? Its like a couple months good and a couple months bad. Vet seems useless in the matter. I hear there is a heartworm for cats now but I am hesitant. Any ideas on how to get rid of these worms for good!!!Or is it something I'll have to learn to live with?