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Equine Encephalomyelitis in India
fibrinous lepto-meningitis over the mesial portion of the cerebral hemispheres.
In one case, a decided cerebral congestion was observed. In the cord, the
dura mater shows a thickened, ground glass appearance indicating a residual
meningitis. Punctate haemorrhages are seen in the grey matter of the cord
(Macalister). The spinal fluid is clear, if under pressure.
Kumri is peculiar in that it appears to possess an enzootic distribution.
Its incidence appears remarkably influenced by seasonal variations. It is a
disease predisposed to by sudden falls in temperature. In recent years,
Sahai has commented on the coexistence of Kumri and equine encephalo-
myelitis in Bihar, which is considered the worst affected province in India.
Describing the histopathology of the disease, Macalister enumerates
all the nerve lesions which have been discussed in equine encephalomyelitis.
There is an exact parallel between these two descriptions, and this writer
goes on to say : " in other diseases in which the nervous system shows infiltra-
tive and degenerative lesions similar to those present in Kumri, there is definite
proof that the causal agent is a virus. Whereas, however, the morbid changes
in Kumri are not inconsistent with the existence of a causal factor of this
class, these appearances do not alone justify the hypothecation of the existence
of such an agent, in face of contrary experimental evidence. Such tissue
changes may be caused by toxic influences of widely dissimilar type." Pre-
cisely what the " contrary experimental evidence " is to which he alludes and
the nature of the toxic factors which lead to the production of a non-inflamma-
tory encephalomyelitis is not clear.
It is a peculiar fact that Macalister confined his studies to the pathology
of the spinal cord, although in several cases, he noted macroscopic brain
lesions. The writer has conducted extensive studies on the brain and spinal
cord of Kumri cases, and the lesions noted histopathologically do not differ
in any degree from those observed in equine encephalomyelitis. The lesions
of the kidney and arterial system were likewise identical. It is interesting
to find that Poyser noted cerebral haemorrhage in certain Kumri cases.
Kumri is a spastic paralysis with marked abduction. This indicates an
upper motor neuron involvement, and, therefore, lesions in the cerebral
cortex affecting the Betz cells, the efferent fibres of which go to form the
pyramidal tract. In other words, Kumri is essentially a disease affecting the
brain in every case. Poyser's observations on the implication of the heart
indicate an impairment of the cranial nerve roots.
Sufficient has been said, therefore, to show the analogy between Kumri
and equine encephalomyelitis and there can be no doubt that Kumri—or,
as it is commonly called, equine paraplegia is, in actual fact, a mild variant
of the more acute equine encephalomyelitis. The three cases observed at
Jullundur early in 1935, from whose nerve tissues successful transmission
experiments were made, were, in fact, diagnosed as Kumri by the Veterinary
Officer-in-charge.
The writer, speaking at the second meeting of the Animal Husbandry
Wing of the Board of Agriculture and Animal Husbandry in India in 1936,
said:—
"Kumri and equine encephalomyelitis represent clinical variations
of a common etiological factor as yet little understood. That
the relationships between the two diseases is an intimate one