Raillietina cesticillus

Raillietina cesticillus
Scientific classification
Kingdom:	Animalia
Phylum:	Platyhelminthes
Class:	Cestoda
Order:	Cyclophyllidea
Family:	Davaineidae
Genus:	Raillietina
Species:	cesticillus
Binomial name
Raillietina cesticillus Molin, 1858

Raillietina cesticillus is a parasitic tapeworm of the family Davaineidae. Sometimes called 'broad-headed tapeworm', it infects the small intestine of chicken and occasionally other birds, such as guinea fowl and turkey, which are generally in close proximity to backyard poultry. It is a relatively harmless species among intestinal cestodes in spite of a high prevalence. In fact it probably is the most common parasitic platyhelminth in modern poultry facilities throughout the world.

It is readily distinguished from the other species of Raillietina. The body size is small, scolex is disproportionately large and uniquely shaped, rostellum is wide, and it employs beetles as intermediate host to complete its life cycle.

R. cesticillus is a small tapeworm measuring about 15 centimetres (5.9 in) in length, and 1.5–3 millimetres (0.059–0.118 in) 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 exceptionall 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.

...
Wikipedia