Beef tapeworm (Taenia saginata) Life cycle, Control & treatment

Beef tapeworm

Taenia saginata(syn :Taeniarhynchus saginata)

(Causes®Beef muscles / bovine cysticercosis / Taenia saginatacysticercosis.)

Morphological and biological feature:

• 4-10 miters in length . (may be up to 25 miters .)
• Scolex possesses 4 suckers but locks of a rostellum and hooks.
• A mature segment in always square shaped .
• Ovary is bilobed.
• Gravid segment are larger than broad.
• In G S, the uterus more or less occupies the whole segment and contains about 100000 eggs.
• Eggs are subspherical (30-50-micron by 20-30m) shaped.
• Indirect life cycle.
• Adult parasites are found in small intestine of man ®F/H.
• Larval stage  cysticercus bovis found in muscle of cattle ®I/H
• About 1000-2000 strobila .

life cycle :

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Indirect life cycle.

Infected  human (F/H)

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passing millions   of eggs daily or intact segments each with 250,000eggs in the human feces

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. eggs survive pasture for several months .

Ingestion by a cattle (I/H) (from pasture /utensils)

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onchosphere travel via the circulation (blood  lymph )to the striated muscle .

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Two weeks later develop into pale semitransparent spot (1-2 mm in diameter )

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About 12-15 weeks later.

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It reaches to its full size ,length 1cm. ( scolex (A large pea)®6-9 mm length into 5 mm in size) i.e.cysticercus bovis .

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Ingestion of raw /inadequate cooked beef /meat by man.

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Man become infected

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Adult developed in S I.

 Longevity of the cyst ®from several weeks to 2 years.

Longevity of the eggs ®33-259 days .

Transmition:

1. Direct: By direct deposition of human feces.
2. Indirect: By use of sewage sludge on agricultural land.
3. Birds: May transport proglottids from effluent outlets.
4. Intrauterine/prenatal: The infection of the calf during 2^nd half of gestation.

EPIDEMIOLOGY:

Developing countries:

• Poor sanitation.
• No/insufficient meat inspection.
• Expensive fuel →Meat uncooked.
• Beef and calves get infection from contaminated hand of cookers.
• Prenatal infection may also occurred.

  Developed country:

• Infection may be high due to use of human sewage as fertilizer on pasture and use migrant labour from country with prevalence of cysticercoids. (Generally Hindus are not infected with the parasite, because of their religious restriction to beef. )

Site of predilection:

• Found in striated muscle (neck, shoulder, hind limb)
• But highest densities in heart and masseters muscle.
• Occasionally also in brain, liver lung and kidney.
• All meat inspection. Cuts are made into heart, masseter and tongue.

Death point of the Cysticercus bovis:

1. Killed by cooking up to 57 degree centigrade
2. Killed by freezing less than 10 degree centigrade

Pathogenesis /clinical signs:

·                                 Cysticerci usually do not cause clinical signs in cattle, even in heavy infection.

·                                 Previous infection confers protective immunity.

·         Experimentally , Myocarditis &heart failure associated, with developing cyoticercl in the heart has found with massive infection to calves.

·         In man, the adult p tapeworm may produce diarrhoea and hunger pains, but the infection is usually asymptomatic and objectionable on aesthetic ground.

Diagnosis:

1. Clinical history.
2. Slaughterhouse carcass inspection

      a) Incised and examined the following parts:

• Inner and outer masseter muscle.
• Tongue
• Heart
• Intercostal muscle and diaphragm.
• Triceps muscle.

  b). Assessment of the carcass:

(Rules are unfit for consumption if two or more living cysts are found more than one inspected site.)

Treatment;

The cysts can be killed in cattle by elevated doses of;

• Praziquantel ; 50 mg/kg body weight
• Albendazole; 3x5 mg/kg Body weight with 1 week interval bur it is expensive.
• Yomesan.

Control:

• High standard of human sanitation.
• General practice of cooking meat thoroughly.
• Compulsory meat inspection.
• Heavy infected carcasses should be condemned
• Avoidance of cutting raw or cooked beef.
• Human sludge should not be used in agriculture field were cattle will graze.
• Education of communities in both sanitary hygiene & cooking of meat in developing countries.
• Regulations for infected carcasses freezing at -10°c for at least 10 days, which is sufficient to kill the cysticerci (or 18°C for 3 days).