The stomach worm is also known as the Physaloptera species and is usually suspected when a dog or cat has persistent vomiting.
There are two species for both dogs and cats which include the Physaloptera rara and the Physaloptera preputialis. Normally, warm blooded animals like coyotes and/or foxes, dogs and cats that ingest insects or prey are the definitive hosts while the insects and the prey that have eaten the parasites are the intermediate host. Once the intermediate host enters the definitive host they then work there way to the stomach and develop into adults. The larvated eggs are passed through the feces and the spread of stomach worms begin.
The disease of the stomach worm is pretty severe and causes gastritis and will cause vomiting long term. The severe vomiting can be caused by just a few adult worms that are presented in the stomach. When a large amount of adult worms are present the vomit will include thick mucosa, and possible dehydration and malnutrition. In some lucky but unlucky cases animals that have stomach worms have no clinical signs.
The Physalotera species in animals that hunt prey or have access to the outdoors and can eat insects like beetles, crickets, or roaches etcetera. The most common place for this to happen is the midwest of the US. The intermediate host has been discussed as being the insects but now we have the paratenic host which is the animals that dogs and cats prey on. The paratenic host or the prey has the larvae in the tissues which involves infection when consumed. The different paratenic host have a wide variety of option which are reptiles, mammals and amphibians. They are significantly why dogs and cats that like to hunt or are outside become infected with the stomach worm. The range of the Physaloptera prepotent period would be 2 to 5 months.
If we were to test before this prepotent period was over the result would be inconclusive. The intermediate host or prey have to be in the environment have to be present for the transmission of infection to occur. When the animal is brought into the clinic we will want to find a diagnosis.
A fecal float or the use of a centrifuge will not be helpful in this certain species due to the low amount of eggs and the gravity they have does not work well with the solution. Really the only effective way is to do a direct smear or identification of them in the actual vomit or by endoscopic recovery of them. Adults can be pink to tan and range from about 3 to 6 cm in length. Once the diagnosis is found you are able to start a treatment plan which could be difficult because you have to do multiple doses of anthelmintics, the doctor can remove the nematode by endoscope followed by another treatment of anthelmintics, or the CAPC “recommends 20 mg/kg of pyrantel be given orally, every 2 weeks, for at least three treatments” (CAPA, 2018). You will want to clean the feces in the environment, make sure that if you have an outside animal that they are limited to the yard and to eliminate hunting and scavenging as much as possible. The owner will want to start a monthly preventative for their animals and to limit the infestation of bugs are the house if they have any. The Physaloptera has has no significant proof that the infection is zoonotic, however it is crucial to clean up feces to make sure that other animals are not consuming them.
What I found really interesting is that the veterinarian is able to take the stomach worms out endoscopically, it would be interesting to see this particular procedure done.