Dipylidium caninum is a cyclophyllid cestode. Commonly known as the cucumber tapeworm or double-pore tapeworm, this cestode commonly infects organisms carrying lice. This can include dogs, cats, and even humans, especially children. In humans, symptoms can include diarrhea and restlessness. Infection is spread through fleas, acting as a vector for eggs. Humans become infected by accidentally ingesting a flea with tapeworm larvae.
Dipylidium caninum can grow to considerable length, adults being about 18 inches long. The scolex of the adult has a retractable helminth with 4 rows of hooks and 4 suckers, typical of cyclophyllid cestodes. Proglottids of the adult worm contain genital pores on both sides (therefore why the worm is also called the double-pore tapeworm), and each side has a set of male and female reproductive organs. Proglottids containing eggs are one mean of transmission (see life cycle).
Intact gravid proglottids are passed in feces or appear through the perianal region of an infected individual. Each proglottid contains several egg packets that are held together by outer membranes. The proglottid disintegrates, releasing the egg packets that are ingested by flea larvae. The ingested embryonated eggs hatch oncospheres that penetrate the intestinal wall of the flea larvae. In turn, cysticercoids develop in the body cavity.
Adult fleas containing infective cysticercoids develop from infected larvae. Through ingestion of infected fleas, humans and animals become infected. Once ingested, cysticercoids develop to adult stage and the scolex attaches to the intestinal wall of its host. The adult worm can release proglottids into the intestine, beginning the life cycle again with proglottids in host feces. Animals such as dogs and cats harbor infected fleas that can be passedmost commonly to human children.
A parasite of relatively low virulence, infected animal hosts show little to no symptoms. Feces can contain visible proglottids, especially noticeable in worse infections. Dipylidium caninum, like other cestodes, produces a very high number of eggs to better infect new hosts. This is due to the difficulty in transmission of the parasite through direct transmission (Mackiewicz, 1988).
In humans, most cases of infection are in children. Symptoms, if any, include diarrhea and restlessness. Infected hosts, either human or animal, are often treated with choice drugs niclosamide or praziquantel. Quinacrine hydrochloride can also be a succesful treatment as well for humans, though not preferred today (Bartsocas, 1966).
Controlling fleas on dogs and cats, the primary hosts, can minimize human infection. Using nematophagous fungi as a biocontrol of D. caninum and other helminthes is shown to be effective (Araujo et al. 2009). In laboratory experiments, nematophagous fungi were effective in controlling D. caninum egg capsules. With further research, it is thought that these various nematophagous fungi could be used for public health in controlling helminth eggs. These public health measures would be most beneficial in geographical areas that find difficulty in controlling flea populations and animal fecal contamination.
Araujo, Juliana Milani, Jacson Victor de Araujo et al. 2009. “Activity of the nematophagous fungi Pochonia chlamydosporia, Duddingtonia flagrans and Monacrosporium thaumasium on egg capsules of Dipylidium caninum”. Veterinary Parasitology. 66:1-2 (2009): 86-89.Edit
Bartsocas, Christos S, and Alexander von Graevenitz. “Dipylidium infection a 6-month-old infant.” The Journal of Pediatrics. 69:5 (1966): 814-815.Edit
Mackiewicz, John S. “Cestode Transmission Patterns.” The Journal of Parasitology 74:1 (1988): 60-71.
[file:///C:/Users/Willis/Downloads/Owen_Dcaninum_NAN_Comments.docx#_msoanchor_1 [NN1]]Look at the reference section of one of the journals to see how to format the names, year, ect.