Synonyms: Gid or Sturdy
Coenurosis is the disease caused by invasion of the brain and spinal cord by the intermediate stage of Taenia multiceps. The syndrome produced is one of localised, space occupying lesions of the CNS.
Incidence
In most countries the distance is much less common that is used to be and relatively few losses occurs.
Etiology
The disease is caused by Coenurus cerebralis which is the intermediate stage of the tapeworm Taenia multiceps which inhibits the intestine of dogs and wild canidae. After having been swallowed by the intermediate hosts, the eggs hatch out and the onchosphere sets free and penetrate the intestine and carried out through the blood stream to the brain and spinal cord for the development into Coenurous cerebralis in about 2-3 months after infection.
Coenurus cerebralis can mature in the brain and spinal cord of sheep, goats, cattle, horses and wild ruminants and occasionally man but clinical coenurosis is primarily a disease of sheep, goat and occasionally cattle.
Pathogenesis
(i) Meningoencephalitis: The migrating onchosphere traumatise the cells of the brain, producing inflammation and causes meningoencephalitis.
(ii) Anaemia and atrophy of organ: If the cyst obstructs the blood vessels, results in anaemia and alsi atrophy of the organ.
(iii) Convulsion: The enlarged cyst in the locomotor and non-locomotor areas of brain causes disruption of the action of these areas of brain resulting in convulsion.
(iv) Atrophy of cranial bones: When the cyst is situated on the upper part of the skull, atrophy of the cranial bone occurs.
Clinical Findings
In acute outbreaks due to migration of larval stages, the animal shows varying degrees of blindness, ataxia, muscle tremors, nystagmus, excitability and collapse.
The most obvious sign is slowly developing partial or complete blindness in one eye. Dullness, Clumsiness, headpressing, ataxia, incomplete mastication and periodic epileptiform convulsion are the usual signs.
The nervous disorder depends on the position of the cyst in the CNS. If the cyst is present on the spinal cord, there is gradual development of paresis and eventually inability to rise. If the cyst is present in the brain localising signs are deviation of the head and circling. There is rotation of the head with the blind eye. In young animals, local softening of the cranium may occur over a superficial cyst and rupture of the cyst to the exterior may follow with final recovery.
The neurological signs are referred to as ‘Gid’ or ‘Stagger’.
Diagnosis
Coenurosis is diagnosed mainly based on symptoms and clinical signs and particularly characteristic gid movement. Radiological examination is helpful in defining the location of the cyst specially if there is a prospect of surgical intervention.
Differential Diagnosis
The condition needs to be differentiated from other local space occupying lesions of cranial cavity and spinal cord including abscess, tumour, haemorrhage. The early stages the disease may be confused with encephalitis because of the signs of brain irritation. Clinically there is little difference and while clinical signs and local knowledge may lead to a presumptive diagnosis, demonstration of metacestode is essential.
Treatment
Surgical drainage of the cyst may make it possible to fatten the animal for slaughter, and surgical removal with complete recovery is possible in majority of cases.
Control
(i) The life cycle of the tapeworm may be broken most satisfactorily by using tenicidal drugs for all farm dogs.
(ii) Carcasses of livestock infested with intermediate stages should not be available to dogs.
