What Is the Life Cycle of the Feline Roundworm?

Feline roundworms can cause vomiting, diarrhea, pneumonia and intestinal obstruction in pets. Understanding the life cycle of the roundworm is important for treatment purposes.

  1. Step One

    • The host passes roundworm worm eggs through feces. The worm grows in the egg for at least one month before it can infect a new animal. The eggs can sit for several months or years before infecting a host.

    Step Two

    • The egg contains a second-stage larva and is able to infect a cat that ingests the egg. The egg hatches in the intestines and the worm tunnels out into other parts of the body. The life cycle continues inside the animal.

    Step Three

    • The larvae move to the lungs. Most of the larvae reach the cat's lungs three days after the initial infection. While in the lungs, the larvae mature into third stage larvae and move through airways attached to the lungs toward the throat. This causes coughing and the worms are swallowed again. The larvae can infect the mammary gland in nursing mother cats and be passed to the kittens.

    Step Four

    • After the worms are back in the intestines, the larvae mature fully and start to mate and reproduce. The worms lay eggs about one week after they end up back in the intestines and the cycle starts over.

    Treatment

    • Deworming products available from veterinarians can help get rid of roundworms, but they may not kill larvae that are in the process of moving to the lungs and throat. Several deworming treatments are usually necessary to make sure the infection cycle does not repeat.