If you check your cat's stools carefully you might find worm segments that have not dried up. (vetinfo.com)
You may have noticed the small white worm segments that look like rice grains in his stools or around his bottom. (happytailsspa-blog.com)
If they do, then the first sign of an infection is usually seeing cucumber - seed — like worm segments on a dog's rear end or in its feces. (sentinelpet.com)