Diphyllobothrium Latum (Fish Tapeworm): Life Cycle and Features

In this article we will discuss about Diphyllobothrium Latum (Fish Tapeworm):- 1. Morphology of Diphyllobothrium Latum (Fish Tapeworm) 2. Life Cycle of Diphyllobothrium latum 3. Clinical Features 4. Treatment 5. Prophylaxis.

Contents:

1. Morphology of Diphyllobothrium Latum (Fish Tapeworm)
2. Life Cycle of Diphyllobothrium Latum
3. Clinical Features of Diphyllobothrium Latum
4. Treatment of Diphyllobothrium Latum
5. Prophylaxis

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1. Morphology of Diphyllobothrium Latum (Fish Tapeworm):

The adult worm is ivory or yellowish grey in colour, measuring 3-10 metres in length. The head (scolex) is small, spatulated or spoon shaped, has a pair of slit grooves (bothria) ventrally and dorsally and has no rostellum (a beak­like projection on the head) and no hooklets (Fig. 107.1). Scolex is followed by “neck” and 3,000 segments (Proglottids, Fig. 107.2).

A single worm may discharge as many as one million eggs (Fig. 107.3) per day.

2. Life Cycle of Diphyllobothrium latum:

When the egg of D. latum passed out along with the faeces of the infected host (man) comes in contact with water, the ciliated embryo (coracidium, Fig. 107.4) escapes from the egg and swims in the water. It is ingested by a Cyclops (Fig. 107.5, 6) and transforms into procercoid larva (Fig. 107.7).

When the infected Cyclops is ingested by a fish, procercoid develops into plerocercoid or sparganum (Fig. 107.8) larva in the fish which is infective to man. On consuming insufficiently cooked fish, man becomes infected. The plerocercoid larva develops into an adult worm, ultimately the eggs are excreted in the faeces.

3. Clinical Features of Diphyllobothrium Latum:

The presence of adult worm in the intestinal tract causes no symptom, but sometimes, non-specific abdominal symptoms have been ascribed. If the worms attach themselves to the jejunum, clinical vitamin B₁₂ deficiency develops. In the laboratory, mircoscopical examination of the faeces will reveal the eggs; sometimes proglottids can be observed in the stool.

4. Treatment of Diphyllobothrium Latum:

Quinacrine hydrochloride, niclosamide and paromomycin are found effective. Pernicious anaemia can be treated with folic acid.

5. Prophylaxis:

(1) Thorough cooking of suspected fresh water fish is important;

(2) Pollution of water can be prevented by efficient .disposal of sewage;

(3) In endemic areas of infection, dogs and cats should not be given fish.