Taenia saginata

general characteristics, morphology, history, epidimeology, life cycle, pathogenesis and lab diagnosis.

1. Taenia saginata

2. Classification Kingdom- Animalia Phylum- Platyhelminthis Class- Cestoda Order- Clyclophyllidea Family- Taeniidae Genus- Taenia Species- saginata

3. General characteristic Taenia saginata commonly known as beef tapeworm; unarmed tapeworm of man It is an intestinal parasite of human and cattle Causes taeniasis in human Infection is due to ingestion of eggs/infective larvae, called cysticerci of Tenia saginata Cysticercus bovis is the larval stage, develop in the muscle of cow and buffalo

4. Cysticercus bovis ; larval stage does not occur in man Larva requires man for further development It does not cause cysticercosis Cattle are intermediate host Human are definitave host

5. History The first report of  Taenia saginata was in 1700 by Audry Taenia saginata was first distinguished from its close relative  Taenia solium  by Goeze in 1782 Leuckart   was first to demonstrate proglottid in 1863 and its development as cysticerci in calf muscle Oliver discovered, immature tapeworm turns into adult in human

6. Geographical distribution Cosmopolitian in distribution

7. Epidemiology Most common in beef eating countries , usually of low socio-economic condition and poor sanitation. 40 to 60 million people are infected worldwide Taenia saginata is prevalent in regions where cattles are raised: Africa, Middle-East, Central and Southern American, Europe and Asia

8. Taenia saginata is the most highly endemic Taenia in the USA In comparision , Australia, Canada and USA are regarded as low endemic area, with prevelance rate of 0.1 percent In African counteries , taeniasis ranged between 0.2–8.1% based on microscopy, and between 0.12–19.7% based on coproAg -ELISA .  In Ethiopia, the percentage of tapeworm self-reporting was high (45.0–64.2 %)

9. Habitat Adult worm lives in small intestine of definitive host Larval stage is found in intermediate host tissue Reservoir Human and cattle like cow and buffalo Source Uncooked or raw meat of beef infected with cysticercus bovis

10. Morphology Adult worm is white, ribbon shaped, flattened and segmented Its length measures about 5-10 meters It is entirely covered by tegument Consists of three portion scolex , neck and strobila

11. Scolex Aslo knows as head Scolex are large, quadrate in shape Measures about 1 to 2mm Absence of rostellum and hooks It has four muscular suckers, which may be pigmented Moves in peristaltic movement in host’s intestine

12. Neck It is short and fragile measures about 3mm to 7mm in length Strobila It consists of 1000-2000 segments or proglottids Immature proglottides are longer (20mm) and narrower(6mm) Mature proglottides are 2cm in length and 2mm-7mm in breadth

13. The length of gravid proglottides is 3 to 4 times than its breadth 15 to 30 lateral branches from uterus on each side which are thin and dichotomous Vaginal sphinchter is present Ovaries are 2 in number, without any accessory lobe 300 to 400 follicles of testes

14. Egg 31-43um in length It is covered by outer embryonal membrane It has brown shell Hexacant embryo with 3 pairs of lancent shaped hooklets C ysticercus 7-10mm in length and 4-6mm in breadth Present in muscle of beef and has invaginated scolex

15. Taenia saginata do not have digestive system, anus, mouth and digestive tract It takes nutrition directly from host through teguments They have complementry male and female reproductive system

16. Fig: morphology of Taenia saginata .

17. Fig: Egg of Taenia saginata

18. Fig: Cysticercus

19. Life cycle Fig: Life cycle of Taenia saginata

20. It has two-stage life cycle: adult in the definitive host(man) and larval in the intermediate host(cattle) Prepatent period - 10- 12 weeks Patent period-decades T. saginata , are the only source of dissemination of embryophores in the environment Eggs ingested by cattle hatch in the digestive tract

21. Release the hexacanth embryos ( oncospheres ) These pass through the intestinal mucosa and migrate via general circulation to the skeletal muscles and heart They develop into cysticerci larvae ( metacestodes ) called cysticercus bovis C ontaminate to humans after maturing for about 10 weeks. Once ingested, they release the scolex , then the tapeworm develops in the human small intestine

22. I n 3 months, mature rings actively migrate through the anal sphincter Gravid proglottid or segments found in feaces The lifespan of cysticerci is variable, some degenerate in 9 months, but others may remain viable for several years

23. Pathogenesis Eating beef meat containing cysticercus bovis are infective Adults worms while living in the intestine usually do not give rise any symptoms Ocassionly , responsible for vague abdominal discomfort, chronic indigestion, anaemia and intestinal disorders, such as diarrhoea alternating with constipation Detection of segments in faeces Unlike   T. solium , the eggs of  T. saginata  are not infectious to humans and their ingestion does not result in cysticercosis

24. Laboratory Diagnosis Intestinal Taeniasis : a) stool examination Direct fecel examinations Cellophane tape technique Concentration method by sedimentation technique (formalin-ether) Brine Flotation Technique b) Molecular methods :DNA probes and PCR Observation of proglottid in stool by naked eye, whitish segment are easily recongsied against dark yellowish mass of stool

25. Eosinophilia Serological test for demonstration of specific antibodies in serum. IHA(indirect heamagglutination assay) , IFA(indirect flourescent antibody) and ELISA are employed for detection of Ab.

26. Clinical manifestation Taenia saginata infection is generally asymptomatic Heavy infection causes weight loss, dizziness, abdominal pain, diarrhoea, headache, nausea, constipation, chronic indigestion and loss of appetite It also causes antigenic reaction that induce allergic reaction It also rarely cause a) Ileus : disruption of normal propulsive ability of the gastrointestinal tract.

27. b)Pancreatitis: Inflammation of pancreas c) Cholescystitis : Inflammation of gallbladder d) Cholangitis : Inflammation of bile duct 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

28. Treatment Drug of choice is praziquantel , a single doe after breakfast(5-10mg/kg) It is effective against adult tapeworm in a single dose and kills cysticerci in high dose (50-100mg/kg) Niclosamide (2gm) ; a single dose in the morning in empty stomach is effective

29. Prophylaxis Sanitary disposal of human feces Adequate meat inspection Cooking beef to >65 degree centigrade or freezing at -20c for 24 hours Stool examination of food handlers of endemic area Avoid eating uncooked vegetables and fruits that cannot be peeled off of sewage disposal area

30. Thank you