How did our cat get worms?

[LivinLaVidaLoki]

Sorry this probably is a stupid question.
We adopted a cat 3 weeks ago. He has settled into our home beautifully and we love him dearly.
He has not yet been outside.

When we bought him home they told us he is flead and wormed with his next worm treatment due in May.

However I have noticed quite a lot of what looks like grains of rice where he is sleeping and Google tells me this is worms commonly caught from fleas or eating birds etc.
He literally has been nowhere and we've not got fleas in the house so I am at a loss as to how this has happened?

You can worm every month if needed. I would re-treat with something from your vets and see if that works.

It only takes one flea or worm egg. They can live in your house without infesting it. Even indoor cats need flea and worm treatments regularly

Our cat was on a 3monthly wormer and she managed to get worms before the next dose so we switched to milbemax from the vet and she’s been fine since. Could well be your cat had worms on board when you got him and you’re just noticing now

Thank you @ItsSnowJokes
Im going to call the vet in the morning. Randomly he did have diarrhea recently but I put it down to changing his food.

Wormer is a treatment, not a preventative. They can literally get reinfected straight after they’ve had the treatment, that’s why you have to do it so often. Chances are it’s picked them straight back up at the rescue before you adopted it.