VPA 211: General Veterinary Parasitology and Helminthology (3+1)

PATHOGENESIS

• Adult worms are not pathogenic in D/H (Dog) but the larval stages are highly pathogenic in I/H (Sheep). In lambs the migrating larval stage causes, “acute menigo encephalitis” which is chronic in nature and associated with one Coenurus or two Coenuri.
• The developing Coenurus produces high degree of brain tissue damage causing neurological condition which is referred to as Gid or Staggers or Sturdy. The neurological symptom depends upon the location of cyst in the CNS.
• If the cyst is located in one of the cerebral hemisphere the animal will hold its head to one side and turn in a circle towards the affected side. The eye on the opposite side may be blind.
• If the cyst is situated in the anterior part of the brain, the animal will hold its head against the chest and may walk with high steps or may walk in a straight line until it meets an obstacle and remain motionless.
• If the cyst is present in the ventricle, the movement will be backward.
• If the cyst is present in the cerebellum, the animal will be hyperaesthetic and may have incoordination, jerky or staggering gait or may remain motionless.
• If the cyst is present in the surface of the brain, the skull may be subjected to “pressure atrophy” and so perforation of the skull may occur.