Roundworms are round-looking worms that thrive by absorbing nutrients from an animal’s food, causing damage to the intestine and interfering with digestion. The three types of roundworms that can affect dogs and cats include T. leonina, T. canis, and T. cati. Generally, the most common roundworm to affect puppies are T. canis, while T. leonina is often seen in dogs and cats.
How Do Dogs Get Roundworms?
Roundworm eggs are passed in an infected animal’s feces. These eggs are then ingested by another animal through contaminated feces, soil, or water or by eating a small rodent. Mothers can also transfer roundworm larvae to her babies before birth.
When the eggs enter the body, they release larvae that mature and mate in the small intestine, and then they lay eggs that are passed in the feces. Other larvae migrate through the body and go to the respiratory system or enter body tissues where they can become encysted in the tissue and pop out during times of stress or pregnancy.
Roundworm Symptoms in Dogs and Cats
The symptoms of roundworms include diarrhea, vomiting, a thin or dull hair coat, lethargy, malnutrition, a distended stomach or potbellied appearance, and abnormal stools. Spaghetti-looking worms may be observed in the vomit or feces, and they can range in size from three to seven inches. If the larvae enter the respiratory system, animals may develop a cough. A heavier infestation may result in intestinal blockage or pneumonia.
How To Know If My Dog Has Roundworms?
Roundworms are diagnosed by viewing the feces under a microscope. Roundworms are positively diagnosed if the eggs are found in the feces.
Roundworm Treatment in Dogs and Cats
Treating roundworms is done with a dewormer containing either Pyrantel Pamoate, Praziquantel, Milbemycin Oxime, or Fenbendazole. Similar to the treatment of other worms, multiple rounds of treatment are required to kill all stages of the worms.
How to Prevent Roundworm in Dogs and Cats
Because roundworm eggs are passed through the feces, picking up feces is key to preventing the spread of these worms. Regularly deworming your pet is also an important step in prevention. Newly acquired animals, babies, and moms should be tested for worms and put on a deworming schedule. (Read Deworming Pregnant Dogs).
Keeping the environment clean of feces and controlling rodents in your environment are also important factors in preventing roundworms. In addition, pets should be discouraged from eating rodents, such as mice.
Roundworms are zoonotic, meaning they can infect humans. Proper hygiene is key to preventing human infection. Washing hands, especially before eating, is crucial.
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Written by: Marty Greer, DVM
Director of Veterinary Services
Marty Greer, Doctor of Veterinary Medicine, has 40+ years’ experience in veterinary medicine, with special interests in canine reproduction and pediatrics. She received her Doctor of Veterinary Medicine from Iowa State University in 1981. She’s served as Revival’s Director of Veterinary Services since 2019. In 2023, Dr. Greer was named the Westminster Kennel Club Veterinarian of the Year.