Notes on Taenia saginata

1. PRESENTED BY
Mrs.J.JEBA.,M.Sc.,M.Phil.,
ASSOCIATE PROFESSOR,
ANNASAMY RAJAMMAL COLLEGE OF NURSING,
ATHIYOOTHU

2. INTRODUCTION
Taenia saginata, commonly known as the beef tapeworm, is a
zoonotic tapeworm belonging to the order Cyclophyllidea and
genus Taenia.
 It is an intestinal parasite in humans causing taeniasis and
cysticercosis in cattle.

3. Cattle are intermediate hosts for T. saginata. Humans are infected
by
Eating cysticerci (larval form) in raw or undercooked beef
The larvae mature in about 2 months to adult worms that can live
for several years; usually, only 1 or 2 adult worms are present.
Adult T. saginata tapeworms are usually 4 to 12 meters in length,
but can be as long as 25 meters.
T. saginata infection occurs worldwide

4. GENERAL FEATURES
Can be 10 meters long though usually 2-5 meters
1000-2000 proglottids (1 cm long) with 1/3 – 1/2 being gravid
Proglottids have 15-20 lateral branches from the uterus and a
lateral genital pore
 Scolex has 4 suckers with a slight apical depression and no
hooklets

6. Transmission
Eating of inadequately cooked beef
Inadequate meat regulation
Use of raw human sewage for fertilizer
Inadequate human fecal sanitation

7. Life Cycle
Prepatent period – 10-12 weeks
Patent period - decades

8. Disease Characteristics
Generally asymptomatic
Diarrhea and abdominal cramps toward the end of the prepatent
period (10-12 weeks)
Rare – intestinal obstruction with a mass of entangled worms

9. Patients may be asymptomatic or have mild digestive symptoms
including epigastric discomfort, nausea, flatulence, diarrhea, or
hunger pains.
Passage of a motile segment (proglottid) often brings an
otherwise asymptomatic patient to medical attention

11. Life Cycle
Infected meat eaten by man
Cysticercus digested out of infected tissue
Scolex exvaginates and attaches to small intestine
Gravid proglottid segments found in feces
Eggs extruded
Infectious for 2-6 months
Eggs or proglottids eaten by cattle
Eggs hatch in duodenum
Embryo passes to tissue via mesenteric venules or lymphatics
Cysticerus stage develops in muscle (infectious for 1 year)
10-12 weeks

12. Diagnosis
Proglottids in the stool
Eggs in the stool
Scotch tape test for eggs on the perineum
Fecal concentration techniques (Kato thick smear, Formyl
ether)
Taenia antigens in the stool

13. Infection
Microscopic examination of stool for ova and proglottids
The stool should be examined for proglottids and ova; ova may
also be present on anal swabs.
The ova of T. saginata are indistinguishable from those of T.
solium (pork tapeworm) and T. asiatica, as are the clinical
features and management of intestinal infections due to these 3
tapeworms

14. Infection
Praziquantel
Alternatively, niclosamide
Treatment of T. saginata infection is with a single oral dose
of praziquantel 5 or 10 mg/kg.
Alternatively, a single 2-g dose of niclosamide (not available in
the US) is given as 4 tablets (500 mg each) that are chewed one
at a time and swallowed with a small amount of water. For
children, the dose of niclosamide is 50 mg/kg (maximum dose 2
g) once.
Treatment can be considered successful when no Taenia ova are
identified in stool 1 and 3 months after treatment

15. Control Measures
Sanitary disposal of human feces
Adequate meat inspection
Cooking beef to >65C or freezing at -20C for 24 hours
Stool examination of food handlers from endemic countries
Avoid eating uncooked vegetables and fruits that cannot be
peeled while traveling in developing countries