WendyLu Smithfield, NC 8/20/2012 9:51:58 PM It is true, I have a 9 wk old, male Boston Terrier, the owners dewormed him at 6 wks old, right before we got him, and than I took him to a vet to double check at 7 wks old, for it has been 5 days later, Marley still had worms, so the vet dewormed Marley again. Now Marley is about 9 wks old and he still has worms. I think this article is very helpful and maybe the vet mentioned it and I must have forgot. But, I do not recall being told that I had to keep deworming him up to 16 wks. Marley is scheduled for another apt on August 27, but I cannot wait that long, for I want Marley to be done with his worms. Marley is a good dog, learning his house training very well, learning to fetch sticks and he is such a good doggy, Marley is very smart. It is terrible that he has to deal with these terrible things.