Occurrence: Worldwide. Species affected: Chicken. Age affected: All.

Causes: Chicken tapeworm- Raillietina species.

Effects: Emaciation, degeneration and reduced growth rate.

Fifty percent of the intestinal tracts of chickens may contain tapeworms (cestodes) if they are reared on range or in backyard flocks. In contrast, birds confined within poultry houses seldom become infected. Tapeworm infestations are now considered rare in intensive poultry-rearing regions. Over 1400 species of tapeworm have been identified in wild and domestic birds. Of these, three families are 10 genera, including Raillietina species affect poultry.

Tapeworms are flattened, ribbon-shaped, usually segmented worms. Millions of eggs may be required to complete the complicated two-hose or three-hose life cycle. The worms are characterised by complete absence of a digestive tract and obtain their nourishment by absorption from the gut contents of the host.

Birds become infected by eating an intermediate host, which transmits a larval stage of the tapeworm to the intestine of the definitive host. The intermediate host may be an insect, crustacean, earthworm, slug, snail or leech depending upon the species of tapeworm. Some larger tapeworms may appear to completely block the intestine of infected birds. Different species vary considerably in pathogenicity so identification as to species is desired.

Some large tapeworms may appear to completely block the intestine of infected birds. Different species vary considerably in pathogenicity so identification as to species is desired.

Tapeworms are flattened, ribbon-shaped, usually segmented worms. Millions of eggs may be required to complete the complicate two-hose or three-hose life cycle. The worms are characterised by complete absence of a digestive tract and obtain their nourishment by absorption from the gut contents of the host.

Most species of worm appear during postmortem examination of the digestive tract. Acute identification is necessary for effective control. A portion of the worm should be removed and viewed under a microscope for detailed identification.

Tapeworms are flattened, ribbon-shaped, usually segmented worms. The worms are characterised by complete absence of a digestive tract.

Most cestodes are usually host specific for a single or a few closely related birds. Identification of the genus and species may provide a clue to the probable intermediate host.

Most cestodes are usually host specific for a single or a few closely related birds. Identification of the genus and species may provide a clue to the probable intermediate host. The diagnositician may then be able to suggest practical control measures.

Completion of a two-host life cycle depends upon a unique set of ecologic conditions. Thus minor changes in flock management may cause a break in the life cycle and affect a useful control measure.

Antihelminthic drugs are not recommended as they are only a short-term remedy. The intermediate host should be identified and controlled.

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