This will reduce environmental contamination for new kittens. New kittens should be appropriately dewormed as recommended by your veterinarian. The first deworming should be given at 2-3 weeks of age. Note that this is prior to the time most kittens are seen for first vaccines. It is entirely appropriate to present new kittens for deworming only.
Adult cats remain at risk for re-infection with roundworms throughout their lives.
Whenever roundworms are seen, the cat should be promptly dewormed. It is appropriate to routinely deworm all cats who remain at high risk for reinfection. For example, it is advisable for cats with predatory habits to have a fecal examination several times a year. Control of insects and rodents is important since they may serve as sources of roundworm infection for cats. Stool should be removed from litter boxes daily, if possible.