The Hardin tribune-herald. [volume] (Hardin, Mont.) 1925-1973, 1938-08-11

Sleeping Sickness
OF Horses

Veterinary Research
Laboratory, Montana Exper-
iment Station, BOZeman
In 1880, a disease of horses in
California, characterized oy
symptoms of brain disturbances
and paralysis, and with a high
death rate was found to be a
true infectious disease and was
given the name of encephalo-
myelitiS, indicating an intlam-
alton of the brain and spinal
cord. In 1881, it occurred again
in California and Nevada,
spreading over large areas. In
1888, an exactly similar disease
appeared in the extreme east
ern states, Virginia, Delaware
and New Jersey. To all appear
ances, the eastern and western
diseases were Identical, but ex-
detrimental study showed that a
horse that was immune to the
western disease could be infect
ed with the eastern virus, and
vice versa, so that we now rec
ognize a western and an eastern
strain" of encephalomyelities.
In these western states we ind
only the western form OF the
disease occurring, so that tor all
practical purposes We may for
get the eastern strain.
In 1888 and 1884, Utah, Idaho,
Wyoming and the western
states generally, reported cases,
and in 1885, Minnesota and the
Dakotas suffered heavy horse
losses. Late in the summer OF
1885 the disease was reported
from a dozen localities in east
ern Montana, progressing as tar
west as Billings. In 1886, IN
Montana, no cases we're report
ed until early in August, when
several cases were found in the
Bitter Root valley, spreading
nOrthWard toward the Flat
head Lake vicinity. In 1887,
relatively few cases occurred in
western Montana, but the dis
ease was reported from many of
the eastern counties. Minneso-
ia, South Dakota, Iowa and 9TH
er midWeStern states had SER
ious outbreaks of encephalomy-
elitis during 1887 Minnesota re-
porting $4,000 cases and South
Dakota $4,000. OF the horses
reported affected in these two
states in 1887, there was a NOR
tally of about 80 per cent.
Utah, Nevada, Wyoming, and
Colorado had reported an av-
erage mortality of about As per
cent in the outbreaks of 1888
"a and IS. Early in July, 1888,
sleeping sickness was again
found in eastern Montana, and
as this is written, it seems evil
dent that there will be a very
general outbreak in that area.
Transmission
In 1888, it was established
that infection could be spread
by mosquitoes, and probably
flies. To what extent mosquit-
oes actually carry the disease
from ranch to ranch is not
known. New cases occasionally
show up a hundred miles from
the nearest sick horse, and cas-
es have developed after killing
frostS have done away with
flies and mosquitoes, SO that
there are means of transmission
that we know little ABOUT so far.
It is very likely, however, that
biting insects are quite a factor
in the spread of encephalomye-
ltiis, for in the majority of cas-
es, the first heavy frost has
ended the disease for that sea-
son.
Symptoms
Encephalomyelitis affects the
horses and mules of all ages
and sexes, is very acute, its
duration being seldom longer
than a week or ten days, and
there is a 1880 per cent death
loss. At the onset of the dis
ease there is a very high fever,
followed in a day or so with
evident brain symptoms. The
horse will not eat or drink, ap-
pears stupid and sleepy. In
broken horses can be ap-
preached and handled, gentle
horses will not lead, etc. In
horses on pasture, the fever
and other early symptoms are
generally unobServed.
Once definitely sick, the SYM
ptoms may vary somewhat.
Many horses stand with the
head low, lips dropping, eyes
half shut, and legs braced,
swaying back and forth. Some
lean against posts or buildings
for support. These are the
sleepy" type, and are most
common. Others, of the walk
ing type, constantly stumble
ahead, seldom stopping except
when humping into fences or
other obstacles. After two or
three days, and in some cases,
from the very first, a paralysis
of the throat makes it difficult,
if not impossible, for them to
swallow food or water. In each
outbreak there are a few very
acute cases that become rapidly
paralyzed, go down, and die in