Stomach Worm Infection (Physalopterosis) in Dogs

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Physalopterosis in Dogs


Physalopterosis is an infection of the gastrointestinal tract, caused by the parasitic organism Physaloptera spp. Typically, only a few worms are present; in fact, single worm infections are common.


There is no age, breed, or gender that is more susceptible to acquiring this condition than others. If you would like to learn more about this disease affects cats, please visit this page in the petMD health library.


Symptoms and Types


An infection of stomach worms caused by Physaloptera spp. can be asymptomatic, meaning that no obvious outward signs are present, or the infection may be apparent by the presence of gastric symptoms. The primary symptom is vomiting, which can be of the chronic or acute form. In some cases, a worm, or multiple worms, will be found in the vomit contents.




Stomach worms are caused by the parasitic organism Physaloptera spp. The worms are typically transmitted when an animal ingests the infective larvae that are residing in an intermediate host. Intermediate hosts, such as grubs, beetles, cockroaches, and crickets, are commonly coprophagous -- meaning they eat feces, thereby propagating the life cycle of the Physaloptera parasite.


The worm can also be transmitted through ingestion of a transport host, such as a bird, rodent, frog, snake, or lizard. Outdoor exposure increases access to these intermediate or small vertebrate transport hosts, increasing the odds of contracting stomach worms. Dogs kept indoors without access to these hosts are less susceptible to infection.




The primary method for identifying and diagnosing worms is through endoscopic gastroscopy, in which a small thin tube with a tiny light and camera at the end is inserted through the dog's mouth and into the stomach in order to visually examine the interior of the stomach. Worms will usually attach to the stomach lining, or to the mucus-covered lining of the intestines.


A careful and thorough exam is necessary for detecting worms because there are generally not many present, and they can be hidden by mucus and stomach contents. Also, at 2.5 to 5 cm long, the worms are quite small.


An examination of the dog's vomit and feces may also reveal an infection of stomach worms if worm eggs are found to be present in the contents.