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Apr 29 2016

Reflections on Intestinal Parasite Control in Household Pets

This blog is not meant to address the myriad of intestinal parasites that prey on our household pets, but rather to address some more specific concerns. It is a misconception that because your pet lives inside with you, with only chaperoned outdoor activity, that he or she is immune to intestinal parasites. This is especially common thinking for house cats who never go outside.  A recent case at our clinic of an usual type of tapeworm infection in four kittens have highlighted the need to be more informative on these parasites and to emphasize the need for regular fecal testing, even for total house pets.

We routinely recommend annual fecal exams on all of our patients to check for intestinal parasites, of which there are many kinds that may affect your pet. They are exposed to them from their mother often, but also later in life from soil, direct contact with feces of other animals, contaminated environments, fleas, eating rodents, frogs, reptiles, and fish, and even from drinking water.  So you may think if you keep your pets inside and have a controlled yard and good flea control that there is little risk of them having intestinal parasites, and while it is true that will greatly decrease their risk, it does not eliminate all potential risk, especially for a particular type of tapeworm.   Most people are somewhat aware of hookworms and roundworms that young puppies and kittens are often born with, but know much less about other parasites, such as coccidia and giardia (protozoan infections not worms), or tapeworms.  What is known about tapeworms is primarily that they are contracted from swallowing fleas and can be seen with the naked eye when they crawl out of the pet’s anus and dry out like grains of rice in their bedding.  All of this is true, but yet an incomplete picture of the intestinal parasites that can infect our house pets.

At Animal Clinic 192 we recently found a seldom seen parasite in the fecal of four littermate kittens, around 6 months old at diagnosis.  One reason the parasite is seldom found is because the eggs shed only periodically and eggs are what we must rely on to find this particular tapeworm, because unlike the flea tapeworm called Dipylidium canine, this tapeworm does not crawl out of the rectum as with the flea tapeworm, but most often remains inside the intestines causing long term consequences.  Also the flea tapeworm seldom sheds eggs internally so finding the adult worm outside of the body is the best way to diagnose that sort of tapeworm, but with this parasite we may need to do multiple fecals if it is suspected because finding the eggs may be the only way (short of endoscopy) to diagnose it.  The other reason it may be overlooked is because it is a type of tapeworm that could easily infect a house cat and often people with house cats decline the fecal exam once they are no longer kittens and have had no outdoor exposure.  So here is the low down on the tapeworm called Spirometra.  Spirometra tapeworms (immature form called pleurocercoid) are found inside the muscles of the intermediate host, which are the sorts of creatures your cat loves to chase, play with, and yes, eat.  Even your indoor cat will often have access to these prey:  mice, lizards, and frogs.  Water snakes and birds are also an intermediate host. These vertebrate creatures have ingested something called a copepod which is a water borne zooplankton that has ingested the embyonated spirometra eggs which were deposited by the definitive hosts like cats, lynx, coons, even dogs (though more rare than cats because of the intermediate hosts most often being preyed on by cats, not dogs). So that is the life cycle in a nutshell.

So what should you do if you suspect your cat has eaten any of these intermediate hosts?  Most certainly, you should consider a fecal exam. However, waiting 10-30 days after the suspected ingestion is wise because it may take that long for development and egg passage to begin.  At the very least an annual fecal parasite exam should be performed even for all house pets, whether known exposure or not.  Also, if there are any clinical signs (even if you have not seen your pet eat one of the suspect creatures) a fecal is indicated.  Not all pets will show symptoms of significance, but some things to look for are unthriftiness of hair coat, failure to grow well if still a growing kitten, extreme hunger despite no or little weight gain or weight loss, diarrhea, vomiting, and a sour odor to the feces.  Also please note that feces may look completely normal and still be infected.  Extreme numbers of worms could lead to more intense symptoms, even vomiting up some worms and possibly intestinal blockage. Of course, the best thing to do is prevention.  Living in Florida however, makes that 100% impossible since lizards get into everyone’s house at some time and often frogs as well, even if rodents are well controlled.  Therefore knowledge of the potential and knowing what to watch for and at least a yearly fecal exam, along with the physical exam, is your best bet to keeping your pet free of the Spirometa parasite.  

Lastly, I wish to mention one other parasite that is very similar to Spirometra and more common in dogs, but also found in cats.  it is also a tapeworm, but again not the sort that comes from fleas.  It is called Diphyllobothrium sp. (Broad fish tapeworm)  It is contracted by eating raw or undercooked fish. This could occur in scavenging activity, but also some people may feed undercooked fish to their pets, even sushi.  At Animal Clinic 192 we had a case last year of this tapeworm in a young dog that had been a stray scavenging for survival before the owners found and adopted him. Since they had not fed him sushi or undercooked fish that is likely where his infection came from.  The worms are very long and will pass sometimes, but often would only be found on a fecal exam.  The treatment for both Spirometra and Diphyllobothrium require very high doses of a specialized dewormer, but can be safely and effectively treated in the veterinarian’s office.  Hopefully, with knowledge and preventative care, together, we can prevent these parasite infections from affecting your beloved pets. 

Spirometra egg

Spirometra egg, credit Animal Clinic 192 case study

Spriometra adult

Spriometra adult, credit Penn Veterinary Medicine

animalclinic192 | cats, Dogs, health, lifelearn, Uncategorized

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