Microbiology & infectious diseases
Parasites-gastrointestinal (not liver)
Dipylidium caninum
Author: Haind Fadel, M.D.
Last author update: 1 January 2015
Last staff update: 18 June 2021
Copyright: 2003-2025, PathologyOutlines.com, Inc.
PubMed Search: Dipylidium caninum[TI]
Table of Contents
Definition / general | Diagrams / tables | Life cycle | Clinical features | Diagnosis | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) images | Differential diagnosis | Additional referencesCite this page: Fadel H. Dipylidium caninum. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parasitologydipylidiumcaninum.html. Accessed January 21st, 2025.
Definition / general
- Common tapeworm of dogs and cats in most parts of the world which may infect humans, especially children
- Human infections have been reported in Europe, the Philippines, China, Japan, Argentina and United States
Diagrams / tables
Images hosted on other servers:
Life cycle
Life cycle
- Usually tapeworm eggs are ingested by flea larvae, which infest areas frequented by dogs or cats
- Cysticercoid larvae persist as the flea undergoes metamorphosis to the adult stage
- Dogs, cats and humans ingest the adult flea containing the infectious cysticercoid
- Children are at highest risk for infection because of their close contact with pets
- Worms mature in the human small intestine and grow up to 70 cm in length
- Infection produces few symptoms
Clinical features
- Most infections are asymptomatic but mild gastrointestinal disturbances may occur
- Most striking feature in animals and children consists of the passage of proglottids, found in the perianal region, in feces, on diapers and occasionally on floor coverings and furniture
- Proglottids are motile when freshly passed and may be mistaken for maggots or fly larvae
- Pets may exhibit behavior to relieve anal pruritis, such as scraping anal region across grass or carpeting
Diagnosis
- Based on finding characteristic eggs, egg packets or proglottids in feces
- Spherical eggs contain a six hooked embryo, measure from 24 - 40 μm in diameter and occur singly or in packets
- Scolex (head) is somewhat elongated with four suckers and a small retractable rostellum
- Proglottids are barrel shaped and possess two genital pores, one on each lateral margin, which give rise to the common name double pored tapeworm
Case reports
- 2 and 4 year old boys with Dipylidium caninum infection (Rev Chilena Infectol 2008;25:465, Indian J Med Microbiol 2013;31:82)
Treatment
- Infection is self limiting in humans and typically clears spontaneously in 6 weeks
- Praziquantel:
- Adults, 5 - 10 mg/kg orally in a single dose
- Not approved for children less than 4 years old but has been used successfully in children as young as 6 months
- Niclosamide is effective but unavailable in United States
- No purge or follow up stool examination is indicated but appearance of proglottids after therapy is indication for retreatment
Gross description
- Dipylidium caninum adults measure 10 - 70 cm long
- As proglottids mature, they break off from the parent stroblia
Gross images
Images hosted on other servers:
Adult tapeworm
Microscopic (histologic) images
Images hosted on other servers:
Eggs, various images
Proglottids
Cross sections
Differential diagnosis
- Other intestinal tapeworms
