Diagnosis. The diagnosis must be based on the disturbance of vision, movement, and appetite, and on the course of the symptoms, as well as on the external signs in the case of such diseases as are prone to become complicated with meningitis.
Prognosis. Sooner or later the case is likely to end fatally, and there is no practical use in treating the patient.
Treatment. If in exceptional cases slaughter is objected to, setons and blisters may be applied to the poll or the parotid region, or the parts may be enveloped in ice bags or compresses of iced water frequently renewed.
ENCEPHALITIS.
Encephalitis, i.e., inflammation of the cerebral substance, is very closely allied to meningitis; in a great number of cases meningitis and encephalitis co-exist. In other cases encephalitis may be found apart from meningitis, and vice versâ. Moreover, many of the symptoms of meningitis are to be found in cases of encephalitis.
Encephalitis may develop as a complication of meningitis. Encephalitis may also follow abundant parasitic infestation, as in cœnurosis (which will be particularly studied as it affects sheep), or microbic infection, the commonest form of which in the ox is tuberculosis. The encephalitis may be diffuse or circumscribed, according to the cause, while the symptoms are varied and numerous. Very frequently, particularly in cases of tuberculosis, encephalitis assumes a chronic form.
Symptoms. The earliest symptoms are extremely difficult to detect, because they are scarcely characteristic and because it is impossible to ascertain the sensations of the animal.
It is only when the disturbances in walking, in the eyesight, in swallowing, etc., are noted that suspicion is aroused.
The symptoms may appear suddenly. Nevertheless it is beyond doubt that there are certain slightly marked prodromata, indicated by diminution of appetite, wasting, and changes in vision. Soon afterwards occur other forms of disturbance, which may be classified under the heading of “motor, visual, nervous, and impulsive.” The patients appear stunned, their movements are slow and hesitating, they partially lose control over their limbs and display lameness, with spasmodic movements of one or two limbs. Examination of the joints shows no injury. The lameness may simultaneously affect two diagonal limbs or two fore and two hind limbs, or even three limbs. This lameness is of central origin.
The ocular disturbance is marked by diminution or loss of vision, by strabismus, or by frequent unconscious movements of the eyes and eyelids, and also more particularly by inequality, contraction or dilatation of the pupils.