Taenia pisiformis

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Taenia pisiformis
Taenia scolex.jpg
Taenia pisiformis scolex
Scientific classification
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Cestoda
Order: Cyclophyllidea
Family: Taeniidae
Genus: Taenia
Species: Taenia pisiformis
Binomial name
Taenia pisiformis

Taenia pisiformis is a common dog tapeworm. It is related to Taenia solium, the pork tapeworm, and to Taenia saginata, the beef tapeworm.

The adult may reach up to 200 cm in length. The definite host is represented by carnivores such as the dog or the cat.

The intermediate host is represented by hares and rabbits, in which we find the mesacestoide (the larval stage) known as: cysticercus pisiformis. This is found in the peritoneum of the intermediate host and can be ingested by the definite host when the dog or cat feeds on the viscera of such an infected intermediate.

Life Cycle

The rabbit [intermediate host] ingests an egg. Then the egg hates in the small intestine, the larval tapeworm go through the intestinal wall and travel to the liver and the blood. The cysticercus develops in the liver for two weeks to four weeks. After that, it comes out into the peritoneal cavity where it attaches to the viscera. Therefore, when the dog, fox, other candis [definitive host] eats the rabbit and ingests the cysticercus the protoscolex attaches to the small interstinal wall, and then the worm begins to form proglottids. Gravid proglottids, containing the eggs and detach from the end of the worm. Then pass out in the feces.

Adult Morphology

The adult stage consists of a scolex with 4 suckers and an armed rostellum, a short neck region, a series of immature proglottids with undeveloped reproductive organs, a series of mature proglottids with fully developed male and female reproductive organs, and a series of gravid proglottids with an expanded uterus filled with eggs.

Metacestode Morphology

For this species, the fully developed metacestode stage is in the form of a cysticercus, and therefore consists of an invaginated scolex surrounded by a fluid-filled bladder.


Common Diagnostic Test

1. Gross examination of the proglottid 2. Fecal flotation [It may bring up the eggs if a gravid proglottid has been broken in the feces]

Clinical Sign

1. Asymptomatic 2. Extremely heavy worm burdens in small dogs my cause blockage of the intestine.

Treatment

Epsiprantel, Praziquantel and Fenbendazole can be treated.

References[edit]

Roberts, L. S., and J. Janovy. Gerald d. schmidt & larry s. roberts' foundations of parasitology. 8th Edition. Missouri: McGraw-Hill Science/Engineering/Math, 2005. pg.347. print.