Taenitaenia solium

BICROBIOLOGY

1. TAENIA SOLIUM MAN BAHADUR RANA,BPH

2. MORPHOLOGY Adult Worms: It measures about 2-3 metres in length. The whole body is divided into 3 parts: head (scolex), neck, and proglottids. Scolex (head): It measures about 1mm in diameter (about the size of pin head) with four suckers . The head is provided with a rostellum armed with a double row of alternating large and small hooklets.

3. Contd… Neck: The neck is short, measuring from 5-10mm in length. Proglottids: It is of three types, Immature, mature and Gravid. Immature: male and female organs not differentiated. Mature: male and female organs have differentiated Gravid: Uteri filled with eggs.

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6. EGGS - As there is no uterine opening, the eggs are liberated by the rupture of ripe proglottids. - Spherical or Brown in colour. - Measures 35-45um in diameter. - The embryophore is brown, Thick walled and radially striated. - Contains an oncosphere with 3 pairs of hooklets. - Does not float in saturated solution of common salt. - Eggs are resistant and may remain viable for 2 months.

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8. Larvae (Bladdder worm) Cysticercus cellulosae : This consist of bladder with one scolex. The scolex remains invaginated with in the cyst wall which can be seen in the naked eye as a milky white spot about the size of pin head. Cysticercus developed in pork meat and live upto 8 month.

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10. Life cycle The worm passes its life cycle in two host . 1. Definitive host - Man 2. Intermediate host – Pig The adult worm lives in the small intestine of man . The eggs or gravid segments are passed out with the faeces on the ground.

11. Contd… The animals swallow these eggs while grazing in the field. On reaching the alimentary canal of the intermediate host, the radially striated walls of the eggs rupture and oncosphere are liberated.

12. Contd… These Oncosphere penetrate the gut-wall with the help of their hooks and gain entrance into mesenteric lymphatic finally reaching the systemic circulation and succesively reach to the liver, right side of the heart, lungs etc. The naked oncosphere filtered from circulating blood into the muscular tissue where they settle down and undergo further development.

13. Contd… The muscle most commonly selected are tongue, neck, shoulder and ham. Oncosphere are trapped in these muscle and developed into cysticercus cellulosae. Man acquires infection by ingestion of raw or undercooked pork containing cysticercus cellulosae

14. Contd… When the cysticercus cellulosae reach the intestine the scolex is evaginated and attach to the intestinal wall with the help of suckers and hooklets Then it grows into an adult worm in about 2-3 months, thus continuing the cycle.

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17. Pathogenecity Mode of infection : Ingestion of Cysticercus cellulosae in raw or insufficiently cooked pork. Pathogenesis and clinical feature: - Ordinarily the adult worms do not produce serious clinical symptoms. - At time they cause vague abdominal discomfort, hunger pain, chronic indigestion, persistent diarrhoea and sometimes constipation.

18. Contd… - These results are mainly due to their large size and substances release by them. - Loss of appetite and eosinophilia are also seen. Cysticercosis: Human cysticercosis is a clinical condition caused by cysticercus cellulosae, the larval stage of T. solium.

19. Contd… Mode of infection: Ingestion of eggs through contaminated food and vegetables or due to poor personal hygiene. Types of Cysticercosis : On the basis of symptoms and location of cysticercus, it is classified as follows.

20. Contd… 1. Symptomatic 2. Asymptomatic Symptomatic: a) Neurocysticercosis .(cerebral or extra cerebral). b) Occular cysticercosis (intraoccular or extraoccular). c) Disseminated (visceral or intramuscular) d) Mixed cysticercosis .

21. Contd… Asymptomatic: In some instances, cysticercosis remains asymptomatic. Laboratory diagnosis : Mainly serological test are used. Sample : Serum and CSF Antibody detection : ELISA, CFT, IFA Antigen dection : ELISA, Western blot. Others method: Plain X- ray, CT-Scan and MRI.

22. Epidemology

23. Laboratory diagnosis 1. Stool examination : Eggs are searched for in stool sample but it does not distinguish between T. solium and T.saginata. 2. Molecular methods : DNA probes and PCR have been developed to detect and differentiate between eggs of T. solium and T. saginata in stool specimen.

24. Treatment - Praziquantel and Niclosamide are used for the treatment of human tapeworm infection. - Niclosamide : single dose of 2.0gm (4 tabs of 500mg) is effective against adult worms. - Praziquantel is the drug of choice for treatment of T. solium infection because it not only kills the adult worms in a single dose, but also kills the cysticerci when taken in high dose for 3-7 days. - Albendazole : 400mg

25. Prophylaxis - Control the source of infection. - Control transmission ways. - Educate the populations - Avoid eating raw or undercooked pork - Wash hands after using the toilet and before handling food. - Wash and peel all raw vegetables and fruits before eating.

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