Spirometra Mansonoides In Dogs And Cats


This is the egg of Spirometra we see on the microscope. Spirometra spp. got into your pet because he ate something that was the first intermediate host, such as a bird, snake or frog. Preventing him from eating those will prevent future infestations with Spirometra.

Spirometra mansonoides is a tapeworm parasite that commonly infects bobcats, domestic cats and dogs.

Unlike the more common tapeworm of dogs and cats, Dipylidium caninum, which uses the flea as its intermediate host, Spirometra have two intermediate hosts.

The life cycle begins with an infected animal (bobcat, dog, cat, racoon, and other mammals) passing eggs in worm segments called proglottids. Eggs mature into a larval stage that infects a copepod, which is a tiny aquatic animal. In the ocean, copepods are a major component of the food source known as plankton. Copepods are equally numerous in fresh water, and may be swallowed by a rodent, frog, snake or bird drinking contaminated water. Thus, the copepod is the first intermediate host and the rodent, frog, snake or bird, is the second intermediate host.

The definitive host becomes infected by eating the second intermediate host. The bobcat is Spirometra’s preferred host, but it can reproduce satisfactorily in your house pet, hunting dog or outdoor cat.

Most people are unaware of their pet’s infestation with Spirometra until we perform a routine fecal flotation. We see the characteristic eggs of the parasite, which appear on the microscope, to me, like a folded omelet. Attentive pet owners may notice proglottids of Spirometra in their pet’s stool or attached to the hair of the perineum.

Spirometra infestation rarely causes overt disease in pets, although vomiting, diarrhea and weight loss are possible when the parasite is present in large numbers.

The risk to humans is discussed in this article.

Dr. Randolph.


  1. Shanice E Williams says:


    I visited the vet with my 32.6lb dog who tested positive for spirometra tapeworms. The vet offered a medication that is $100 called Dronset. I asked her is praziquantel effective as well and she said yes but if I get the over the counter Bayer formula in store instead of the 3 pills listed as her dosage i would need to give her 11 tablets a day for 2 days… so 22 34 mg praziquantel tablets in 2 days is a correct comparison of dronset or no?

    I received advice to give her 3 tablets and then 3 tablets 10 days later from someone else.. I am very afraid to follow the instructions with such a smaller dog as she is and there was no direction on how to administer my dog 11 PILLS! Is it morning? Night? Noon? With food or no?

    It seems dangerous and incorrect to me.

    • I’m sorry, but I don’t have enough information on the pills to give you an answer, but I do have some concerns: 1, as far as I know praziquantel is an FDA-controlled medication. If I am correct in that, no one should be selling it OTC, which would then make me question the safety, purity and source. 2, it takes a LOT of praziquantel to kill Spirometra, WAY more than Dipylidium or other species of tapeworms. Therefore, it’s not surprising that your doctor’s fee would be the amount you stated. I would feel most comfortable recommending you let your pet’s veterinarian treat him safely and effectively. Thank you for reading http://www.MyPetsDoctor.com.

  2. Kayleigh says:

    Hi Dr. Randolph,

    Is Spirometra transmissible to humans FROM the dog, the dog’s stool, or the dog’s saliva? Please advise.

    Thank you!

  3. Lanette says:

    Our 7 month old puppy has an extreme infestation of Spirometra that has been resistant to treatment. We are now trying natural remedies in hopes of saving him. Can this be passed on to humans or our other dog? We’ve been battling this since October 2014.


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