Canine Roundworm Infection

The roundworm like many other worms has several complex and environment-dependant stages of development. For Toxocara eggs, the most complex development cycle of the two, begin by being passed in the host animals feces where it has a month long growth cycle. It's at this second stage where it's ready to infect its next host and can live at this stage for months, sometimes years.

Incredibly, the roundworm can only develop to its third stage from a canine, thus another animal may pick up these second stage larvae which hatch in its intestinal tract, leave and lay waiting in a new patch of feces for a canine to pick it up.

Once consumed by a dog, the parasite then migrates to its lungs to complete its third stage of development. They navigate through the airways and up to the throat causing the dog to cough. Sometimes this causes pneumonia if infection is bad enough. Once coughed up, the dog then swallows the young worm where it burrows its way back to the intestinal tract where it continues to mature to their last stage of growth. Once sexually mature, roundworms immediately begin to mate. This entire lifecycle can take as little as 4 to 5 weeks with new larvae already in the host's intestines.

If the canine is pregnant, the larvae will not follow the path to the lungs to be coughed up, but instead the hormones in the female dog will redirect the larvae to move through the placenta infecting the unborn puppies or through the mammary glands to infecting the nursing puppies.

Puppies affected by roundworm often vomit them up putting these worms up for display. Coughing, developing a potbelly, diarrhea, weakness, emaciation (extreme weight loss) and pneumonia are all common signs and can be severe enough to cause death if not treated soon enough.