The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1909-07-03
HOW TICKS SPREAD FEVER.
By Exterminatlng the Ticks Texas
Fever Can be Stamped Out and the
Quarantine Removed.

The microscopic parasite which
causes the disease known as Texas
fever or tick fever of cattle is found
in the blood of affected animals and
is transferred from one to another by
means Of the fever tick. A remark
able feature Of the transaction is
that the disease producing parasites
are transmitted through the eggs of
the tick that draws the blood, and
not directly by the old tick, as an
engorged tick after dropping from
the host (cow) dies without ever
attaching itself to another animal.
But its offspring produced by the
eggs laid after 1t drops off and be-
fore 1t dies, carry the infection and
inoculate the first cow they get on.
The length of time elapsing be-
tween the exposure of susceptible
cattle to infection by ticks and the
appearance Of Texas fever among
them is dependent upon the climate
and the development of the ticks.
Thus, If northern cattle are placed
on pastures, highways, or in pens,
cars, etc., in summer Immediate
ly after the premises have teen in
tested with ticks from southern cattle.
Texas fever may occur in frora thirty
to sixty days, as the female ticks
which drop from southern cattle must
lay eggs and these must hatch before
the northern animal becomes infested
with ticks and thereby inoculated
with the disease. After the seed ticks
become attached to the animal the
disease will appear in about ten days
tr summer or somewhat longer
period In winter. In fact, the disease
may occur before the ticks are large
enough to be seen without a very
careful search.
One objection that has been ad-
vanced against the fact that the cat
tie tick Is carrier of Texas fever is
that cattle are sometimes found 10 be
suffering with the disease without
showing the presence of ticks on
their bodies. This condition in the
case of southern cattle may be ex-
planned by the fact that the animal,
already had its blood infected with
the parasites and under normal con.
ditions was resistant to Texas fever;
however, as result of lowered vi
tality caused by some other disease
or by exposure. privation,. injury,
rough handling, etc., this resistance
has been reduced and finally over
come. and the parasites at last sue
ceed in producing the disease. On
the other hand, when this disease is
observed In northern animals, the
young seed ticks may be so small and
so few In number as to he unob-
served
Under certain conditions, as when
living on horses, mules, etc., the ticks
lose their infectiousness, and when
southern cattle not previously infest-
ed with any but these non-infectious
ticks come in contact with infectious
ticks they are just as susceptible as
cattle raised On tick-free pastures.
Many cattle appear perfectly
no nd
ticks and have the fever parasite in
their blood. Sometimes the owners
can net understand why such ami
mails should be regarded as danger
Gus to others. and consider it unjust
tnat they should be subjected to
quarantine restrictions. The fact is
that such cattle have usually con-
tracted the disease in a very mild
form at an early age and have be-
come immune to further attacks, al
though still carrying the parasites in
their blood. They are dangerous be-
cause the fever parasites in their
blood may be transmitted at any
time to susceptible cattle BY ticks.
While the disease may be produced
artificially by inoculating suscep-
tible animal with the blood of an in
fected one, 1t Is spread naturally only
by the ticks. BY exterminating the
ticks, therefore, the disease can be
stamped out, and the quarantine can
then be removed.
The discovery of the part played by
the tick In the spread of Texas fever
was made by the Bureau of Animal
Industry of the United States Depart
ment of Agriculture in 1891, and the
same principle has since been found
to apply to the transmission of ma-
laria and yellow fever from man to