Microbiology & infectious diseases
Parasites-gastrointestinal (not liver)
Taenia saginata
Author: Haind Fadel, M.D.
Last author update: 1 January 2015
Last staff update: 12 August 2022
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Taenia saginata[TI] cestodes full text[sb]
Table of Contents
Definition / general | Epidemiology | Pathophysiology | Diagrams / tables | Clinical features | Incubation period | Diagnosis | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Additional referencesCite this page: Fadel H. Taenia saginata. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/parasitologytaeniasaginata.html. Accessed December 18th, 2024.
Definition / general
- "Beef tapeworm"
- Tapeworm infections have been reported since 1500 B.C. and recognized as one of the earliest human parasites
- Taenia saginata was differentiated from T. solium infection by the late 1700s
- However, the exact life cycle of T. saginata was not discovered until 1863, when cattle was identified as the immediate host
Epidemiology
- Especially common in Middle East, Africa, Europe, Asia, Latin America
Pathophysiology
- Humans are the sole definitive host
- When humans ingest infected raw or incompletely cooked beef, the cysticercus develops into a reproductive adult in the small intestine in 2 - 3 months
- Symptoms are rare but may include abdominal discomfort and diarrhea
- Unlike T. solium, the eggs of T. saginata are not infectious to humans and their ingestion does not result in cysticercosis
Diagrams / tables
Images hosted on other servers:
Life cycle
Clinical features
- For humans in good health, there are few serious symptoms associated with tapeworm infection
- For both T. saginata and T. solium, patients may have diarrhea, constipation, flatulence, hunger pain, weight loss; rarely appendicitis
- Most common complaint is embarrassment and discomfort when proglottids crawl out of anus
- Taeniasis infection may compromise the immune system; especially in young children, this may have a profound effect on their health
Incubation period
- Takes 5 to 12 weeks for worm to mature into adulthood in the human intestine
- Usually only a single worm is present at one time, although multiple worms have been reported
Diagnosis
- Diagnosis is made by finding eggs in stool, using direct or concentration techniques or in the perianal folds, using the cellophane tape technique
- Eggs are spherical and measure 31 - 43 μm in diameter
Case reports
- Four cases of Taenia saginata infection with an analysis of COX1 gene (Korean J Parasitol 2014;52:79)
- Polyparasitism with long term abdominal pain (Turkiye Parazitol Derg 2013;37:157)
Treatment
- Both T. saginata and T. solium are treated with oral medication, usually a single dose of niclosamide
- Therapy is usually very successful and most cases are completely eradicated
- If proglottids reappear, retreatment is administered
Microscopic (histologic) description
- Proglottids of taeniids have a characteristic lateral protrusion known as the genital pore
- Careful injection of India ink through the genital pore, using a tuberculin needle and syringe, may succeed in outlining the uterus
- Gravid uterus of T. saginata has 15 - 20 lateral branches, compared to 7 - 13 for T. solium
- Proglottids may also be cleared overnight in glycerol or stained with carmine or hematoxylin using published procedures
- If recovered, the scolex of T. saginata can be identified by the presence of four suckers and the absence of hooks on the crown or rostellum
- Shell is thick, radially striated and contains a six hooked embryo
- Eggs of all Taenia species are indistinguishable and should be reported only as Taenia eggs
Microscopic (histologic) images
Images hosted on other servers:
Gravid uterus of T. saginata with > 13 lateral branches
Additional references
