LAKSHMI
SAHAI
349
DIAGNOSIS, RESULTS OF TRANSMISSION EXPERIMENTS, ETC.
By the time the author arrived on the scene eight horses had already been
affected and two of these were in a moribund condition. These died on the
subsequent day. The clinical picture presented by the animals, the post
mortem findings, the course of the disease and the occurrence of so many cases
within such a short space of time suggested the possibility of some infective
agent at work and equine encephalomyelitis was suspected. Material was
at once forwarded to Mukteswar for biological examination as no facilities for
such examination existed locally and at the same time hexamine treatment
of the remaining horses was started which as already stated proved ineffective.
Meanwhile, other possible causes of the trouble were thought of and in
this connection the possibility of vegetable poisoning seemed to merit especial
consideration in view of the common belief among the people in the locality
that grass obtained from a certain farm was in some way connected with
causing symptoms such as were seen in these horses, a possibility which could
not be entirely ruled out in view of the well-known existence of certain plants
which can exercise a poisonous effect on the central nervous system and the
fact that although the Mounted Military Police horses at Jamshedpur are
maintained ordinarily on hay, bran and oats with boiled linseed once a week,
this year partly with a view to conserving the supplies of hay and partly with
a view to supplying some sort of green stuff to the animals of which they are
ordinarily completely deprived, these horses had for sometime before the
outbreak started been fed on grasses obtained from this particular farm
(lucerne, guinea-grass and ordinary grass) and continued to be so fed for some-
time afterwards. Chemical examination of the grasses, however, failed to
reveal any poison. This was at first regarded as not entirely to exclude the
possibility of vegetable poisoning as by the time samples of these grasses were
collected, they had so completely changed their texture that it was considered
not improbable that any poisons present might have disappeared. In this
connection it is interesting to note that though no grass either from this farm
or any other source is being fed, the disease has recurred this year (1937-38)
among these horses with exactly similar clinical manifestations to those seen
before.
Coming to the question of an infective agent, Mukteswar found that of
two rabbits and two guinea-pigs inoculated sub-durally with brain material
from one of the affected horses, both the rabbits failed to develop the infection
while of the guinea-pigs one died after showing paraplegic symptoms and
the other survived after a febrile reaction. Similar results had been obtained
by Shirlaw [1934] in the Multan outbreak and this led the author to suspect
that probably a virus was the etiological factor concerned, but unfortunately
Mukteswar was unable to repeat the results when supplied with some further
material from two horses later. In this connection, however, it is necessary
to mention that this material had been taken from horses which had been
affected for about a year and, therefore, the possibility of such material hav-
ing become avirulent cannot be entirely ignored.
M