Diagnosis And Treatment Of Echinococcosis And Clinical Manifestations Of Other Tapeworm Infections

Diagnosis: Strong clinical suspicion is necessary to suggest the diagnosis of hydatid disease.

1. Blood: Mild eosinophilia is invariably present.
2. Casoni’s reaction: Intradermal injection of 0.2ml sterile hydatid fluid leads to formation of a large wheal in halp an hour which disappears in 2 hours. This test is suggestive, but not specific since cross-reactions may occur with several other parasites.
3. Immunological tests such as precipitin reaction with hydatid antigen, hemaglutination test using sensitized sheep red cells, etc. are positive in 90% of hepatic and 60% of pulmonary lesions.
4. Immunoelectrophoresis and ELISA techniques are specific, though technical difficulties restrict their wide use.
5. X-rays. The cysts are radio-opaque and are seen as sharply outlined masses in the lungs.
6. Ultrasonography gives the most valuable information about the nature of the mass and its contents. Isotopic scans of the liver bring out cold areas.

In any case, closed aspiration is generally contra-indicated since escape of the contents may result in anaphylactic shock and secondary infection.

Treatment: Medical treatment offers only slight relief, though, recently large doses of mebendazole have been reported to be beneficial in arresting the growth of the cysts. Albendazole, a benzimidazole carbamate, given in a dose of 5 to 7 mg/Kg body weight twice a day for 5 to 6 weeks is reported to kill the hepatic cysts. The drug is teratogenic and therefore, should not be used in pregnant women. Planned surgery offers the best chance of cure for symptomatic cysts.

Prophylaxis: Care should be taken in handling dogs. Domestic dogs should be regularly de-wormed. Three courses of arecoline 4mg/5Kg body weight eliminate T. echinococcus and Hymenolepis nana in dogs. Contamination of children’s playground with dog’s feces should be avoided.

Infection by Diphyllobothrium latum is extremely rare in India. It is more common in Russia, Baltic regions, Switzerland and Japan. The adults are seen in human small intestine and it may range in length from 3 to 10 meters. The eggs are operculated. Two intermediate hosts are required for completing the lifecycle- the fresh water Cyclops and fresh water fish. Man gets infected by eating uncooked fish. The parasite may compete for vitamin B₁₂ in the intestine, leading to vitamin B₁₂ deficiency in the host. Niclosamide is an effective vermicide.

Hymenolepis Nana (Dwarf Tapeworm)

This is the smallest tapeworm found in man, measuring 1 to 4 cm in length. Children acquire infection by swallowing eggs. The larvae hatch out and grow in the small intestine. Noclosamide is very effective in clearing the infection.

Hymenolepis Diminuta

This tapeworm is a parasite primarily affecting rats and mice. Man is accidentally infected by consuming the infective larva present in fleas, along with cereal grains. Niclosamide is curative.

Dipylidium Caninum

This is a tapeworm seen in cats and dogs. Many get infected accidentally by consuming the infective larvae present in fleas. Niclosamide is curative.