Raillietina cesticillus

Description

Raillietina cesticillus is a small tapeworm measuring about 15 cm in length, and 1.5 - in width. It is whitish in colour, highly elongated, dorso-ventrally flattened, and entirely covered with a tegument. The body consists of the head region called 'scolex', an unsegmented 'neck', and a highly segmented body proper called strobila. The strobila is composed of a chain of ribbon-like proglottids. The scolex bears an apical rounded rostellum surrounded by four suckers. Unlike other species of Raillietina, it is exceptionally broad-headed, the rostellum is very prominent and protruding, and the suckers are small. In addition the rostellar hooks are arranged in two rows. A significant diagnostic character is an unusually numerous hooks, which may be as many as 500. The suckers are poorly developed, and completely devoid of special devices or spines. The scolex measures ~134 μm in diameter, and the hooks are 7-10 μm in length.

Life cycle

The tapeworm completes its life cycle in two different hosts, the definitive host being mostly of chickens, and the intermediate hosts are beetles. More than 100 species of beetles are known to act as intermediate host.

Pathogenicity and pathology

The adult parasite inhabits the small intestine. Generally infection is asymptomatic, and there are no reports of clinical disease. It is considered as the least pathogenic species of Raillietina. However, under heavy loads of experimental infections, pathological symptoms include degeneration of epithelial cells, enteritis, and macrophage infiltration of lymphocyte.

Diagnosis and treatment

Infection is diagnosed by identifying proglottids in the faeces, or adult worms in the intestine upon autopsy. Fenbendazole is 100.0% efficacious when administered in the diet at 240 ppm (50.9 mg/kg BW) for 6 days in naturally infected broilers; but less effective at lower doses, without affecting the appetite nor it induced any adverse effects on weight gain. Albendazole is a better drug of choice in terms of efficacy and sideeffects.

References

References

1. Olsen OW. (1974). "Animal Parasites: Their Life Cycles and Ecology". University Park Press, Baltimore, US.
2. Baker DG. (2008). "Flynn's Parasites of Laboratory Animals". Blackwell Publishers.
3. Kaufmann H. (1996). "Parasitic Infections of Domestic Animals: A Diagnostic Manual". Birkhäuser Verlag, Basel.
4. Hambridge G. (2011). "Diseases And Parasites Of Poultry". Daya Publishing House.
5. (1985). "Studies on the pathobiology of chicks experimentally infected with ''Raillietina cesticillus'' (Cestoda)". Indian Journal of Poultry Science.
6. (1992). "Efficacy of fenbendazole against naturally acquired ''Raillietina cesticillus'' infections of chickens". Avian Pathology.
7. (2007). "Determination of the Anthelmintic efficacy of albendazole in the treatment of chickens naturally infected with gastrointestinal helminths". The Journal of Applied Poultry Research.