A kitten can get infected with worms through milk, and an adult cat can get infected with flea eggs or by contacting another animal. In addition to deworming, it is important to treat your cat against fleas (preventively) on a regular basis since worms can be contracted by infected flea eggs.
In the absence of regular flea and worm treatments, these parasites will keep facilitating each other, exposing your cat to both.
However, you cannot deworm your cat and treat it for fleas at the same time. So, How long should you wait between treating your cat for fleas and worms?
It is recommended that you wait at least 48 hours before applying spot-on flea treatment on your cat after giving him worming tablets. Alternatively, if you administer your cat spot-on flea treatment first, you should wait at least two weeks before giving him worming tablets.