Special Veterinary Pathology

TAPE WORM INFECTIONS

Definition

• Tapeworm disease is caused by cestodes and tapeworm infection causes more damage only in young animals

MONIEZIASIS AND TAENIASIS

Aetiology

• M. expansa – Cattle
• M. benedini and M. expansa– Sheep and goat
• Dipylidium caninum, Taenia pisiformis, T. hydatigena, Multiceps multiceps, Diphyllobothrium latum – Dogs

Pathogenesis

Tape worms cause damage to the host by

• Injury and enteritis – by suckers and hooks.
• Absortion of the nutrients in gastrointestinal tract
• Obstruction and voluulus
• Macrocytic anaemia – by d. latum which absorbs vit b12, folic acid and iron

Clinical signs

• Diminished appetite and in dogs due to severe irritation of anus drags themselves sitting on their buttocks.

Lesions

• The larval stage or bladder worm of the parasite produces more damage
• Cysticercus cellulosae is the bladder worm of Taenia solium in man which infects shoulder, neck, diaphragm, tongue, intercostal, abdominal and cardiac muscle of pigs
• The affected meat is called 'measly pork'
• Cysticercus bovis is the bladder worm of human adult tape worm – T saginata found in the muscles, liver, heart etc. of cattle
• The affected meat is known as ‘measly beef’.
• Coenurus cerebralis is the bladder worm of dog tape worm M.multiceps found in the central nervous system of sheep causing 'Gid'
• Cysticercus ovis is the bladder worm of dog tape worm T.ovis seen in the muscle of sheep and goat
• C.tenuicollis is the bladder worm of T. hydatigena found in the liver,mesentery and omentum of sheep, goat and pigs
• Hydatid cysts is the bladder worm stage of genus Echinococcus found in the liver,lungs and other important organs and the condition is called as echinococcosis or hydatid disease
• Two species of E.granulosus and E.multilocularis occurs. Dogs and wild carnivors act as a final host of E.granulosus whose larvae occurs in sheep and it also infect cattle, horse, pig,monkey, rodents and human and other species.
• Foxes, dogs and cats act as a final host of E.multilocularis whose larvae occurs in various rodents and human

Liver-Hydatid cyst

 

Diagnosis

• Examination of eggs or segments of parasites in the faeces
• Hydatid cyst can be identified by histopathological examination, complement fixation test, delayed hypersensitivity test, haemagglutination tests and fluorescent antibody test