344
Equine Encephalomyelitis in India
Most of the paraplegia cases commenced with severe dullness, marked
lameness in one limb, either fore or hind, quickly followed by incoordination,
usually posterior but occasionally anterior, with marked abduction. Several
cases showed acute jaundice, while symptoms of colic in some and catarrhal
fever in one, ushered in the lameness. A prefebrile stage was noted in several
cases.
In 1932 (November and December), at Sargodha, twenty two fillies went
down with ' paraplegia'. Four fillies had arrived six weeks previously from
Saharanpur. The cases ranged from mild to severe. Seven animals were
affected with cerebral symptoms, six of which developed repidly from early
paraplegia, and the temperature of four rose markedly (106.5°) before death.
The remaining cases, all of which were relatively mild, were considered cured at
the end of a month.
At Lahore (September, 1935—January, 1936), twenty-two cases occurred
among the horses of the 6th D. C. O. Lancers. Only one animal showed acute
cerebral symptoms and died. Routine temperature taking was adopted at the
commencement of the outbreak. Twelve cases developed fever of four to five
days duration and two of these manifested paraplegia immediately on abate-
ment of fever.
The specific symptoms noted in this series of outbreaks were paraplegia or
cerebral meningitis, some of the latter developing from the former. It may
be adduced, therefore, that the disease exists in three forms, cerebral, spinal
and mixed cerebro-spinal.
In mild outbreaks, the affection is spinal and the symptoms are paraple-
gia, i.e. paralysis or incoordination of the hind quarters, obviously dependent
on involvement of the lower part of the spinal cord. It may be considered
that this structure becomes progressively involved, till the higher centres are
reached, with the eventual development of meningo-encephalitis. It may
just as easily be argued that the brain and the cord are affected simultaneously
but that the brain lesions develop more slowly, and, accepting this hypothesis,
which is borne out on later pathological examinations, the cerebral lesions can-
not be explained on the basis of an ascending infection from the cord.
Among the general symptoms noted may be mentioned colic, nasal catarrh,
retention or incontinence of urine, weakness in the loins, loss of sensation to
forceful pin-pricks in the posterior (occasionally anterior) limbs and most
frequently the perineal region, pyrexia, jaundice, ' fits ' and delirium.
In the outbreaks recorded, all these symptoms were noted but they were
most irregularly distributed among the affected horses, any of which might
show only one of the above symptoms, while others might evince a combina-
tion of several. It is this peculiar feature of the symptomatology which has,
apparently, baffled so many observers in the past and which certainly entitles
equine encephalomyelitis to be termed a disease with a symptom complex.
It will also be observed that these outbreaks possessed a definite seasonal
incidence. They all commenced at the beginning of the cold weather, when
the variation between night and day temperatures is very considerable and
accompanied by humidity and damp, usually with cloudy, overcast skies.
Valuable as these observations are, it was not until the Multan outbreak
(1933-34) that the syndrome of equine encephalomyelitis was intensively