Taenia saginata

Notes on Taenia saginata

1. TAENIA SAGINATA 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

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

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

7. 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

8. 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

9. 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

10. 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

11. Diagnosis of Taenia Saginata 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

12. Treatment of Taenia Saginata 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

13. 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