Are heartworms visible? - Prestige Animal Hospital
Heartworms are not visible like other parasites, how people think, "Oh, I could see a worm on a fruit from a dog or a cat or something to that extent." No, they're not visible. They travel in the blood. The only way they're visible is with imaging, x-rays, and ultrasound. But otherwise, no, they're internal. They're inside the body.