Roundworms in Dogs

"Roundworms in dogs (“ascariasis”) is caused by two different species of “ascaroid nematodes”, Toxocara canis and Toxocara leonina. T. Canis is considered more important, as it can be transmitted to humans (zoonotic) and is fatal in young puppies. Roundworm in dogs is characterized by a dull coat, rough skin, vomiting, and a protruded belly. In the initial stages, cough and mild pneumonia is common. In young puppies, enlargement of the liver and accumulation of granules on the kidney may cause death. Diagnosis requires the detection of roundworm eggs in the feces. Treatment can be completed by using anti–helmintics, anti–parasitic drugs and can be inhibited by using preventive doses of anti–helmintic drugs."

Life Cycle of Roundworms in Dogs:

In general, both species of roundworms infesting dogs can be transmitted by different modes. Known ways of transmission include Contamination (soil, environment), tran placental (from the mother before birth) and by feeding contaminated milk of the bitch to puppies. Infective larvae of dog roundworms usually transfers to the lungs, blood stream and causes pneumonia and coughing in young pups.  The liver can be infested via the hepatic portal vein. As larvae develop into adult worms, adult female roundworms lay eggs in the intestine, which then pass out of the body through the feces.

pictures of roundworms
Pictures of Roundworms
(Source: CDC)

In feeding bitches, some larvae may reach the mammary gland, where they are then transmitted to puppies during feeding.

Initially, the infective larvae roam around the host’s body. It reaches into the lungs, liver, kidney and many other vital organs, but remains in the intestines, once the roundworm becomes an adult.

Depending on the vital organ infested, different roundworm symptoms will appear.

Signs and Symptoms of Roundworms in Dogs:

Initial respiratory signs in dogs, especially in young puppies are revealed as a cough, difficultly breathing and finally pneumonia. Skin roughness, dull coat, anorexia (avoidance of food), protrusion in abdomen that looks like a “pot”, repeated vomiting and finally loss of body condition, may represent a large heavy infestation of adult roundworms in dogs.

Roundworm in puppies is more severe and death may occur, due to an intolerance to respiratory and digestive infections.

Diagnosis of Dog Roundworms:

Clinical signs and history of pregnancy can help in confirming a canine roundworm problem. In the laboratory, spherical or oval, pitted shelled or smooth shelled eggs must be differentiated for two different species i.e. T. canis and T. leonina respectively. T. canis, should be carefully identified, as it has a zoonotic importance, i.e. and it can be transmitted to humans too.

Treatment of Roundworms in Dogs:

Different anti–helmintic (worming) drugs like Fenbendazole (50 mg/Kg B.W Oral), Mebendazole (140 mg Per Oral), Flubendazole (22 mg/Kg B.W for 2 Days), Praziquantel Injection (5.5 mg/Kg SC/IM), etc. are effective treatments for round worms in dogs. These drugs can be used in different combinations, with the medication selected based on the severity of the roundworm problem.

Selamectin is an anti–parasitic drug, which is considered effective against roundworms in dogs. It can be administered as a single dose, or 2 equal doses, but must be administered a month apart. Different side effects and sensitivities are associated with selamectin; so ask your veterinarian about potential side effects.

Preventive doses of anti–helmintics, three times a year can prevent the infestation of roundworms in dogs. There are other tools that can be used, as bitches must be screened for any abnormality; including worm infestation before breeding, and should be kept in isolation, during pregnancy.

There are some over the counter products that can be purchased that when provided 1x a month will protect against dog roundworms.  These include Heartgard Plus (prevents various types of worms) and Sentinel (protects against roundworms, fleas and other parasites).

A homeopathic or natural approach to prevention of roundworm and other parasites is Parasite Dr. . If combines several ingredients known to repel worms and other parasites such as Neem. It may provide an extra level of natural support for your dog.

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Dobson, J.M, Text Book of Small Animal Medicine (W.B Saunders London. 2001)

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