J. F.
SHIRLAW
339
Hurst has attempted a classification of neurotropic viruses according to
the distribution of the lesions encountered on histological examination of the
brain, a feat which presupposes that one is dealing with a pure single type
virus and one somewhat complicated by the fact that small laboratory animals
are in themselves liable to a specific encephalomyelitis, which may flare up on
the depressant action induced by the inoculation of a neurotropic virus isolated
from a different animal species. Hurst sums up these difficulties in expression,
from the point of view of etiological, pathological and clinical considerations,
in one pregnant sentence : " The various forms of virus encephalomyelitis
bear no closer relation, one to another, than does smallpox to measles."
When we remember the intense concentration of highly skilled workers in
those countries afflicted with the disease and the controversies that have arisen,
the difficulties of the isolated worker in India, on similar problems, may readily
be realised.
II.—HISTORY OF THE DISEASE AND ITS DISTRIBUTION IN INDIA
Equine encephalomyelitis is not a disease new to India. Ancient Hindu
writings refer to a disease which Léclainche identifies as a specific meningo-
encephalitis. In a Persian translation made by order of the Emperor Shah
Jehan of a Sanskrit compilation ' by a society of learned pundits ' called
' Saloter ', reference is made to a ' dreadful malady ' of horses which is recogniz-
able as " mad staggers " and in which the symptoms bear an undoubted re-
semblance to present day equine encephalomyelitis. A variant of this condi-
tion—in the same writing—is attributed to the horse's being seized by ' Wind '
in the hind quarters, and the ensuing description conforms to the more modern
descriptions of Kumri. Moorcroft, one of the earliest veterinary pioneers in
India, regarded Kumri as a cerebral affection and demonstrated an excess of
cerebro-spinal fluid which could be ' drained off the dead subject by opening
the occipito-atloid articulation '. (Smith—" History of Veterinary Litera-
ture ".)
Current veterinary opinion in India considers that equine encephalomye-
litis and Kumri are distinct and separate disease entities. The term " encepha-
lomyelitis " is used at the moment, therefore, to denote that symptom-complex
which the writer first observed in the recorded outbreak at Multan [1933] and
which corresponds in symptomatology with that recorded by workers in other
countries where the disease is enzootic. These symptoms are referable,
chiefly, to involvement of the higher nerve centres, although no case is ever
encountered in which the higher and lower (spinal cord) centres are not simul-
taneously affected. It is important to observe that Kumri is considered a
sporadic disease with subacute symptoms and equine encephalomyelitis an
epizootic disease with acute or peracute symptoms.
It is a surprising fact that equine encephalomyelitis only sprang into
prominence in 1933, since when it has assumed great importance and occasion-
ed much thought among veterinary workers in India. A study of existing
records shows, however, that the increase of the disease may be more apparent
than real and that many outbreaks have passed unnoticed or been ascribed to
other causes.