346                  An Outbreak of Equine Encephalomyelitis

After these cerebral symptoms had subsided, the animal developed hemiplegia
with a tendency to go round in a circle. The condition of the animal got
steadily worse and it succumbed three weeks later.

In most cases, the symptoms of paraplegia were seen to progress only to
a point after which they became stationary. There was no loss of appetite
or other disturbance of health and such animals would perhaps have lived
indefinitely, had they not been destroyed.

It may be stated that while a febrile phase of a few days' duration, prior
to the onset of symptoms of paresis, is considered to be a characteristic feature
of equine encephalomyelitis of virus origin, in none of the horses which were
involved in this outbreak was any rise of temperature at any stage of the
disease noted (except in No. 12 already referred to, the result probably of
violent struggling and excitement). The outbreak that occurred during the
winter of 1937-38 was also characterized by an entire absence of any pyrexial
phase, a feature which serves to distinguish these outbreaks sharply from
those which occurred at Multan and in Kashmir.

In practically all cases there was some degree of retention of the urine
amounting in the worst affected cases to complete suppression. In the
majority of cases the urine was definitely thick and gluey due to the presence
of a large amount of mucus and this character is of some diagnostic importance.

None of the animals revealed any interference with the function of the
anal sphincter.

In one case the paralysis also involved the retractor muscles of the penis
which used to hang down out of the sheath.

Swelling of the near hind fetlock was seen in one case, while one case
(No. 13) also showed, coincident with the attack of paraplegia, a filaria worm
in the near eye which, however, disappeared before any operative treatment
could be carried out. Later, this animal went completely blind in this eye,
though it recovered from the paraplegia.

A similar worm was also seen in another horse, involved in the 1937-38
outbreak, but its removal failed to bring about any amelioration of the symp-
toms.

In all the animals the appetite remained normal throughout and though
some of them were kept under observation for months, none showed any
signs of muscular atrophy or skin lesions, indicative of trophic disturbances.
There was no loss of sensation in the hind limbs in any of the animals nor was
any hypersensitiveness elicited on application of pressure over the loins.

Briefly summarized, the symptoms in the majority of the animals were
mainly those of paraplegia of varying degrees combined with the retention,
either partial or complete, of urine in the worst affected cases. In acute
cases, the brain was also affected, especially in the earlier stages.