Toxocara/Roundworms

Young puppies and kittens less that 6 months old are most commonly infected with roundworms. T.Canis affects dogs, T cati affects cats and T. leonine affects both dogs and cats. Toxocara spp. eggs within the environment are infective, via ingestion, to people and other dogs and cats. Infection with Toxocarra spp. is the most common cause of human visceral and ocular larva migrans. Young children are most susceptible.

The parasite is usually discovered incidentally during a routine fecal examination, or infection is never detected. In overt cases, presence of worms in feces or diarrhea, a pot-bellied appearance in young puppies or kittens, or occasional vomiting with or without worms may prompt the owner to seek veterinary attention. Typically, no physical abnormalities are noted. It is possible for young puppies and kittens with severe roundworm infections to have a pot-bellied appearance and /or evidence of diarrhea or intestinal obstruction due to worm burden. IT HAS BEEN SPECULATED THAT ESSENTIALLY ALL PUPPIES HAVE TOXOCARA.

The primary mode of transmission of T. canis is transplacental from the infected bitch to puppies. Puppies and kittens may also be infected with T. canis or T. cati, respectively, by nursing an infected lactating dam or queen. The transmammary route is the principal form of transmission in cats. Fecal-oral transmission is also a possible route of infection, as is ingestion of other host such as rodents. After infection, the parasite may migrate through the liver into the lungs within the wall of the gastrointestinal tract or somatically within the tissues. Puppies and kittens may begin to shed eggs within 2.5 to 3.5 weeks and generally continue to do so until age 4 to 6 months. Eggs are highly resistant and long-lived within the environment. Children playing in contaminated areas can become affected.

The Center for Disease Control and association of Veterinary Parasitologist recommend de-worming all puppies beginning at 2 weeks with additional treatments at 4, 6, and 8 weeks of age. These recommendations aim to reduce zoonotic risk by decreasing environmental parasite burden. De-worm puppies and kittens even if fecal results are negative to ensure removal of prepatent worms prior to shedding. Most de-worming medications are effective against Toxocara and many products used for heartworm prevention are also effective against roundworms. This is a very good reason to have your pet on monthly heartworm prevention medication.